“Gun Glossary Of Terms, Ammunition, Firearms”

Our goal is to have the most comprehensive list of terms in our GUN GLOSSARY of any site on the internet!  We are constantly searching out new terms, words, and definitions. If you do not see what you are looking for all you have to do is contact us and we will find it and get it posted.


If you have a verifiable term or a photo to match any of the terms we have listed you are welcome to send it into us for posting, you will receive recognition for your contribution. Many of the terms listed include photos and dictionary correct pronunciations. We hope that as the shooting public grows and new technology comes into play that our GUN GLOSSARY OF TERMS will never be finished!                                        

Glock 18c Full Auto Pistol


Currently we have hundreds of terms listed and we update the list weekly.


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>Example Glossary Term: Pistol 


(ô′tə-măt′ĭk)   (pĭs′təl)

Automatic pistol may refer to:

Semi-automatic pistol, a type of self-loading handgun that can be fired in semi-automatic mode, firing one cartridge for each pull of the trigger.

Machine pistol, a handgun-style, magazine-fed and self-loading firearm, capable of fully automatic or burst fire, and chambered for pistol cartridges.

Accidental Discharge

ăk′sĭ-dĕn′tl  -  dĭs-chärj′

The event of a firearm discharging (firing) at a time not intended by the user. An unintended discharge may be produced by an incompatibility between firearm design and usage, such as the phenomenon of cooking off a round in a closed bolt machine gun, a mechanical malfunction as in the case of slamfire in an automatic weapon, user induced due to training issues or negligence, or a simple accident.


An unexpected and undesirable discharge of a firearm caused by circumstances beyond the control of the participant(s) such as a mechanical failure or parts breakage. There are very, very few firearms related "accidents" and if the "4 Rules" are followed there will hopefully be no injury.

Accidental Discahrge Accidental Discahrge                                                                   Glock Accidental Discharge Glock Accidental Discharge

ACP Automatic Colt Pistol
.45 ACP

Stands for "Automatic Colt Pistol." Used to designate certain cartridges first chambered in Colt automatic pistols--.25 ACP, .32 ACP, .380 ACP, .38 ACP, .45 ACP















AAC                       Advanced Armament Corporation

AAR                       After Action Review

ACC                       Remington ACCelerator

ACOG                    Advanced Combat Optical Gunsight

ACP                        Automatic Colt Pistol

ACR                        Adaptive Combat Rifle (Remington)

ACS                        Adaptable Carbine/Storage

AD                          Accidental Discharge NO SUCH ANIMAL! See ND

AE                           Action Express, i.e.; .50 AE

AFA                        Armed Females of America

AJHP                      Aluminum Jacketed Hollow Point

AK                          Avtomat Kalashnikov/AK47/AK74

AO                          Adjustable Objective

AP                          Armor Piercing

APFSDS                Armor Piercing Fin-Stabilized Discarding Sabot

API                         Armor Piercing, Incendiary

APT                        Armor Piercing, Tracer

AR                          ArmaLite Rifle, AR-15

ART                        Adjustable ranging telescope

ASA                        Australian Shooting Association

ATM                       At This Moment

AW                          Assault Weapon

AWB                      Assault Weapon Ban

ACP                        Automatic Colt Pistol

ACP                        Automatic Colt Pistol

AD                          Accidental Discharge

AE                           Action Express

AFA                        Armed Females of America

AMP                      Auto Magnum Pistol

AP                          Anti-Personnel

AP                          Armor-Piercing

APCR                     Armor Piercing Composite Rigid

APDS-T                 Armor-Piercing Discarding Sabot, Tracer

APFSDS                Armor-Piercing Fin-Stabilized Discarding Sabot

AP-I                       Armor-Piercing Incendiary

AUTO                    Automatic Colt Pistol (same as the "ACP", not to be confused with "10mm Auto")

AWARE                 Arming Women Against Rape and Endangerment


BALL                      Ball Ammo/FMJ/TMJ

BAR                       Browning Automatic Rifle

BATFE                   Bureau of Alcohol Tobacco Firearms Explosives

BBL                        Barrel/Bull Barrel (Rifle barrel that is thicker than the normal hunting rifle barrel)

BBWC                    Bevel-Base Wad Cutter

BC                          Ballistic Coefficient

BCG                       Bolt Carrier Group

BCM                      Bravo Company MFG

BFH                       Barrel, Forged, Hammer (BFH)

BG                         Bad Guy

BHP                       Browning Hi-Power/P-35

BM                         Bushmaster

BMG                      Browning Machine Gun

BOB                       Bug Out Bag

BOD                       Born On Date

BOF                        Bureau of Firearms

BP                          Black Powder

BPCR                     Black Powder Cartridge Rifle

BPE                        Black Powder Express

BPV                        Bullet Proof Vest/Individual Body Armor

BR                          Bench Rest

BRR                        Bench Rest Remington

BT                           Boat Tail

BUG                       Back Up Gun


C&R                       Curio & Relic

CAL                        Caliber

CAR                        Colt Automatic Rifle/CAR-15

CARL                     Curio and Relic License, 03 FFL

CAS                        Cowboy Action Shooting

CB                          Cast Bullet

CC                          Concealed Carry

CCL                        Concealed Carry License

CCO                       A 1911 Classic Commander slide on an Officer frame

CCP                        Concealed Carry Permit

CCRKBA                Citizen's Committee for the Right to Keep and Bear Arms

CCW                       Concealed Carry Weapons

CF                           Centerfire

CHL                        Concealed Handgun License

CIII                         Class III FFL - dealer of NFA firearm

CL                           Remington Core-Lokt

Clip                         A strip of metal that is used to hold cartridges together to facilitate the loading into an internal rifle magazine.

CLP                        Cleaner, Lubricant, Preservative

CMP                      Civilian Marksmanship Program

COA                       Citizen(s) Of America

COF                       Course Of Fire, shooting stage in pistol event

COG                       Center Of Gravity

COM                      Center Of Mass/Center Mass

CPHV                    Center to Prevent Handgun Violence

CPL                        Concealed Pistol License

CQ                          Close Quarter(s)

CQB                       Close Quarter(s) Battle

CQC                       Close Quarter(s) Combat

CRL                        Curio and Relic License, 03 FFL

CTR                        Compact/Type Restricted

CUP                       Copper Units of Pressure

CWS                       Cold War Shooters


DA                          Double Action

DA                          Double Action

DAA                       Double Action Automatic

DAO                       Double Action Only

DCM                      Director of Civilian Marksmanship

DD                          Daniel Defense

DEWC                    Double Ended Wad Cutter

DF                          Drop Free

DGI                        DIRECT GAS IMPINGEMENT

DI                           DIRECT IMPINGEMENT

DPICM                  Dual-Purpose Improved Conventional Ammunition

DPMS                    DPMS Firearms, LLC/Defense Procurement Manufacturing Services

DROS                     Dealer's Record of Sale

DVC                       Diligentia Vis Celeritas - Latin for Accuracy, Power, Speed


EAA                        European American Arms

EDC                       Every Day Carry - Knife, gun

EDM                      Electrical Discharge Machining

EDW                      Every Day Wear

EMP                       Enhanced Micro Pistol - Springfield Armory

EOP                        Elevated Optical Platform

ERC                        Extended Range Carbine


FA                           Full Auto

FATS                      Firearms Training Simulator

FC                           Forcing Cone

FCG                        Fire Control Group

FFL                         Federal Firearms License

FMJ                        Full Metal Jacket

FML                       Fully Metal Lined

FN                          Fabrique Nationale d'armes de'Guerre/Flat Nose

FNH                       Fabrique Nationale d'armes de'Guerre (National Factory of War Arms)

FOB                       Forward Operating Base

FOID                      Firearm Owner's Identification Card

FORS                     Front-Opposite, Rear-Same (Sight adjustment mnemonic.)

FOV                       Field Of View

FP                           Flat Point / Firing Pin

FPS                         Feet Per Second/Firing Pin Spring

FS                           Front Sight/ Full Size (5" Government 1911)

FSB                         Front Sight Block (Gas Block)

FST                         Front Sight Tower / Winchester Fail Safe Talon (Black Talon)

FTE                         Failure To Eject

FTF                         FireArms Talk Forum/Failure To Feed/Failure To Fire/Face To Face (sale)

FTN                        Failure To Neutralize - penalty

FTRTB                   Failure To Return To Battery, slide fails to return a new round from the magazine to the chamber and lock

FUBAR                  Foobared Up Beyond (All Recognition/Any Repair)

FATS                      Firearms Training Simulator

FFIT                        Fast Female Incapacitation Technique


GA                          Gauge -shotgun bore diameter

GAP                       Glock Automatic Pistol

GC                          Gas Check

GCA                       Gun Control Act (of 1968)

GDHP                    Speer Gold Dot Hollow Point

GI                           Government Issue

GOA                       Gun Owners of America

GPU                       Gas Piston Upper

GR                          Grain


H&H                       Holland & Holland

H&R                        Harrington & Richardson

HBWC                    Hollow-Base Wad Cutter

HC                           Hard Cast

HD                          Home Defense/Heavy Duty

HEAT                     High Explosive Anti Tank

HP                          Hollow Point/Home Protection

HPBT                     Hollow Point Boat Tail

HPJ                        Remington High Performance Jacketed (Golden Saber)

HS                          Hydra-Shok

HSC                        Handgun Safety Certificate

HST                        Hammer, Sear, & Trigger


IBA                         Individual Body Armor = Bullet Proof Vest

IBS                          International Bench rest Shooters

IDPA                      International Defensive Pistol Association International Defensive Pistol Association

IHMSA                  International Handgun Metallic Silhouette Association

ILA                          Institute for Legislative Action - NRA

IMBEL                   Indústria de Material Bélico do Brasil (Military Material Industry) a Brazilian state company, founded in 1975.

IMR                        Improved Military Rifle

IPSC                       International Practical Shooting Confederation International Practical Shooting Confederation

IWB                        Inside the Waistband, holster

IDPA                      International Defensive Pistol Association

IWB                        Inside the Waistband, referring to holsters


JBB                         Jack Bauer Bag

JDJ                          J. D. Jones www.sskindustries.com

JHC                         Jacketed Hollow Cavity

JHP                         Jacketed Hollow Point

JMB                       John Moses Browning

JPFO                      Jews for the Preservation of Firearms Ownership

JSP                         Jacketed Soft Point


K98                         German Mauser 98 in karbine length

KAC                        Knight's Armament Company

KYPD                     Keep Your Powder Dry


LAC                        Law Abiding Citizen

LC                           Long Colt

L-C/T                      Hornady Lead Combat/Target

LCP                         Lightweight Compact Pistol

LCR                         Lightweight Compact Revolver

LE                            Law Enforcement

LEA                         Law Enforcement Agency

LEAA                      Law Enforcement Alliance of America

LEO                        Law Enforcement Officer

LF                            Lethal Force

LFI                          Lethal Force Institute

LGS                        Local Gun Shop

LHP                        Lead Hollow Point

LOS                        Line Of Sight

LR                           Long Rifle/Lower Receiver

LRN                        Lead, Round Nose

LRPK                      Lower Receiver Parts Kit

LSR                         Light Sniper Rifle

LSWC                     Lead Semi-Wad Cutter

LSWCHP-GC         Lead Semi-Wad Cutter Hollow Point -Gas Check (Keith, hollow cavity)

LTC                         Lead Truncated Cone

LTL                          Less Than Lethal

LV-JHP                    Low Velocity-Jacketed Hollow Point

LWC                       Lead Wad Cutter


M193                     5.56x45mm 55-grain ball cartridge.

M195                     5.56x45mm grenade launching blank.

M196                     5.56x45mm 54-grain tracer cartridge, red cartridge tip.

M202                     5.56x45mm 58-grain FN SSX822 cartridge

M755                     5.56x45mm grenade launching blank specifically for the M234 launcher.

M855                     5.56x45mm 62-grain FN SS109 ball cartridge, green tip w/steel penetrator and a lead core.

M855 LF                62-grain green tip w/tungsten penetrator and a steel core. Lead Free

M856                     5.56x45mm 64-grain FN L110 tracer cartridge

M995                     5.56x45mm 52-grain AP cartridge, black cartridge tip.

MAG                      Box Magazine/Magnum

MC                         Metal Cased

ME                         Muzzle energy/Middle East

Mils                        Milliradians

MIM                      Metal Injection Molding/Powder metal processing

Mk262                  5.56x45mm 77-grain Open-Tipped Match/Hollow-Point Boat-Tail cartridge.

MK318                  5.56x45mm 62-grain Open-Tipped Match/Hollow-Point Boat-Tail cartridge.

MLU-26                Early USAF designation for 5.56x45mm ball cartridge produced by Remington.

MM                       Millimeter

MN                        Mosin Nagant

MOA                     Minute Of Angle

MOB                      Middle Of Back

MOD                     Moderator

MOE                      Magpul Original Equipment

MRWC                  Mid-Range Wad Cutter

MSH                      Main Spring Housing

MV                         Muzzle Velocity


NAA                       North American Arms

NATO                    North Atlantic Treaty Organization

NBRSA                  National Bench rest Shooters Association

NCIC                      National Crime Information Center

ND                          Negligent Discharge

NDF                       Non-Drop Free - original Glock magazines were designed to stay in the gun if the magazine release was pressed                                 and there were rounds remaining in the magazine

NEF                        New England Firearms

NFA                       National Firearms Act (of 1934 )

NFML                    Non-Fully Metal Lined magazines also known as Non-Drop Free (NDF)

NGT                       New Gun Test

NRA                       National Rifle Association

NSSF                      National Shooting Sports Foundation

NRMA                   National Reloading Manufacturers Association

NSSF                      National Shooting Sports Foundation


O/U                       Over/Under

OAL                       Office of Administrative Law

OODA                   OODA Loop, Observe, Orient, Decide, and Act. It takes 0.25 of a second to cycle through this decision process.

OOS                       Out Of State

OC                          Open Carry

OM                        Oscar Mike/On the Move

O/S                        Over/Sized

OTB                       Out of The Box

OTM                      Open Tip Match

OWB                      Outside the Waistband, holster

OWB                      Outside the Waistband, referring to holsters


PB                           Lead/Lead Bullet

PBR                        Point Blank Range

PDS                        Piston Driven System RRA

PDSC                     Piston Driven System Carbine RRA

PDSP                     Piston Driven System Pistol RRA

PDSR                     Pistol Driven System Rifle RRA

PDW                      Personal Defense Weapon

PERP                      Perpetrator, criminal

PIRC                       Pre-Incident Response Conditioning

PIRT                       Pre-Incident Response Training

PK                           A 7.62 mm general purpose machine gun designed in the Soviet Union and currently in production in Russia

PKM                      It ("Kalashnikov's Machine-gun Modernized") current, modernized, product-improved version of the PK model

PL                           Remington Power-Lokt

POA                       Point Of Aim

POI                         Point Of Impact

POST                     Peace Officer Standards and Training

POV                       Privately Owned Vehicle

PPC                        Pindell-Palmisano Cartridge

PRI                         Precision Reflex Inc.

PRS                        Precision Rifle/Sniper

PSI                          Pounds Per Square Inch

PSP                        Pointed Soft Point/Plated Soft Point

P&R                       Pinned barrel and Recessed cylinder


Q                             Torque

QA                          Quality Assurance

QC                          Quality Control

QFT                        Quoted For Truth

QTY                        Quantity


RBC                        Rifle Bore Cleaner

RDK                        Rapid Deployment Kit

RDS                        Red Dot Sight

RE                           Receiver Extension (Buffer Tube)

REM                       Remington

RF                           RimFire

RFB                        Rifle, Forward-ejecting Bullpup

RIA                         Rock Island Arsenal

RKBA                     Right to Keep and Bear Arms

RN                          Round Nose

RNL                        Round Nosed Lead

RR                           Range Report

RRA                        Rock River Arms

RUM                      Remington Ultra Mag

RSO                       Range Safety Officer


S&H                       Sharpe & Hart

S&W                      Smith & Wesson

SA                           Semi Auto/Springfield Armory/Springer/Single Action

SAA                        Single Action Army

SAAMI                  Sporting Arms and Ammunition Manufacturers Institute

SAF                        Second Amendment Foundation

SAM                      Shooters Arms Manufacturing (in the Philippines)

SAR                        Search And Rescue

SAS                        Second Amendment Sisters

SASS                      Single Action Shooting Society

SBR                        Short Barreled Rifle

SBS                         Short Barreled Shotgun

SCAR                     Special Operations Forces (SOF) Combat Assault Rifle

SCBS                      Shooter's Choice Bore Solvent

SCSA                      Steel Challenge Shooting Association SCSA

SD                           Self Defense/Sectional Density

SDG                       Self-Defense Gun

SE                           Special Edition

SJSP                       Semi-Jacketed Soft Point

SLR                         Self Loading Rifle

SMG                      SubMachine Gun

SMLE                     Short Magazine Lee Enfield- the .303 caliber British Army rifle

SN                          Serial Number

SNAFU                  Situation Normal, All Foobared Up

SOP                        Standard Operating Procedure

SP                           Soft Point/Spire Point

SPC                        6.8 Special Purpose Cartridge

SPL                         Sound Pressure Level

Spl.                         Special - As In .38 Spl.

SPR                        Special Police Rifle/Special Purpose Rifle

SPRG                     Springfield Armory

SRT                         Special Response Team/Swift Response Team

SS                           Stainless Steel

SS109                    NATO code for the M855 (US CODE) 5.56x45 62 grain FMJ

SSA                        Single Action Army (Colt's SA Revolver/Colt 45)

SSAA                     Sporting Shooters Association of Australia

SSS                         Shooting Southern Style (canebrake style)

STA                        Shooting Times Alaskan

STE                         Shooting Times Easterner

STHP                      Winchester Silvertip Hollow Point

STW                       Shooting Times Westerner

SUR                        Sport Utility Rifle

SWAT                    Special Weapons And Tactics

SWC                       Semi-Wad Cutter

SWS                       Superior Weapons Systems

SX                           (Hornady) Super eXplosive

SXT                         (Winchester) Supreme eXpansion Talon (Black Talon)


TC                           Truncated Cone/Thompson Center

TCU                        Thompson/Center

TDI                         Tactical Defense Institute

TFL                         The Firing Line

TMJ                        Total Metal Jacketed

TOT                        Time On Trigger

TPF                         Ten Percent Firearms

TRP                        Tactical Response Pistol


UBR                       Utility/Battle Rifle

UPLULA                Universal Pistol Loader - UnLoader

USPSA                  United States Practical Shooting Association

USRAC                  U.S. Repeating Arms Company


VCDL                     Virginia Citizens Defense League

VLD                        Very Low Drag


WAGC                   Women Against Gun Control

WC                         Wad Cutter

WCF                       Winchester Center Fire

WIN                       Winchester

WMR                     Winchester Magnum Rimfire

WP                         White Phosphorus/Willy Pete/Whiskey Papa

WWB                     Winchester White Box/Wally World Bullets


XM287                  5.56x45mm 68-grain ball cartridge produced by Industries Valcartier, Inc. An Improved version was also produced designated XM779.

XM288                  5.56x45mm 68-grain tracer cartridge produced by Industries Valcartier, Inc. An Improved version was also produced designated XM780

XM777                  5.56x45mm ball cartridge.

XM778                  5.56x45mm tracer cartridge.

XM996                  5.56x45mm so-called "Dim Tracer" with reduced effect primarily for use with night vision devices.

XTP                        (Hornady) eXtreme Terminal Performance


YHM                      Yankee Hill Machine

YOM                      Year Of Manufacture


Z                              Zed/Zero/0/



n (ak-shuh)

The mechanism of a gun, usually breechloading, by which it is loaded, fired, and unloaded. The operating mechanism of a gun - firearm involved with presenting the cartridge for firing, and in removing the spent casing and introducing a fresh cartridge.

 Firearm Action

Firearm Action

Action Shooting

(ăk′shən)    (sho͞ot)

A generic term for a variety of shooting games usually characterized by extreme speed of fire, relatively powerful handguns, medium to large targets and short to medium ranges. Often called "Combat Shooting." IPSC-style competitions, bowling pin and falling plate matches are all typical of this type of shooting. Practical shooting is a sport which challenges an individual's ability to shoot rapidly and accurately with a full-power handgun, rifle, or shotgun. To do this, shooters take on obstacle-laden shooting courses called stages, some requiring many shots to complete, and others just a few. While scoring systems vary between practical shooting organizations, each measures the speed with which the stage is completed, with penalties for inaccurate shooting.

Cowboy Action Shooting Cowboy Action Shooting                                                                IPSC Shooting Competition IPSC Shooting Competition

Adjustable Stock

ad·just′a·ble -  stŏk

The stock is the wooden, polymer, or metal handle of a long gun that extends from the trigger back to where the gun is braced against the shoulder. An adjustable stock is one that can be easily lengthened or shortened to fit shooters of different sizes.

Adjustable Polymer Rifle Stock Adjustable Polymer Rifle Stock                                                    Adjustable Wood Rifle Stock Adjustable Wood Rifle Stock

Adjustable Trigger

ad·just′a·ble - trĭg′ər

A trigger that can be easily adjusted by the user. Adjustable triggers are common on specialized target-shooting firearms, but rare on self defense firearms.

 Metal Adjustable Trigger Metal Adjustable Trigger Polymer Adjustable Trigger Polymer Adjustable Trigger

Air Gun

[′er ‚gən]

Not a firearm but a gun that uses compressed air or CO2 to propel a projectile. Examples: BB gun, pellet gun, CO2 gun. An air gun or airgun (also called pellet gun or rarely a gas gun) is any one of a variety of guns that propel projectiles by means of compressed air or other gas, in contrast to firearms which use a propellant charge. Both the rifle and pistol forms (air rifle and air pistol) normally fire metallic projectiles, either pellets or spherical balls based on the BB size of birdshot - although a few fire darts.

Air Gun Rifles
Air Gun Rifles
Air Gun Pistol
Air Gun Pistol










Ambidextrous Safety

[¦am·bə¦dek·strəs]    (sāf′tē)

A manual, external safety which can be easily reached with either hand. Usually one lever on each side of the firearm. A safety catch that can be operated by either hand. Of benefit to left-handed shooters and in the event of an injury to the right hand.

Ambidextrous Safety Ambidextrous Safety


(ăm′ō) or am•mo (ˈæm oʊ)

Ammunition, projectiles to be fired from a gun.  Ammunition consisting of a cylindrical casing containing an explosive charge and a bullet; fired from a rifle or handgun.

Liberty Civil Defense Ammo
Liberty Civil Defense Ammo



















am·mu·ni·tion (ăm′yə-nĭsh′ən)

Ammunition is gunpowder and artillery, or broadly anything that can be used in combat including bombs, missiles, warheads, landmines, naval mines, and anti-personnel mines. The word comes from the French la munition which is all material used for war. The collective term for all types of ammunition is munitions.

The purpose of ammunition is to project force against a selected target. However, the nature of ammunition use also includes delivery or combat supporting munitions such aspyrotechnic or incendiary compounds. Since the design of the cartridge, the meaning has been transferred to the assembly of a projectile and its propellant in a single package.

The "packaged" components that are needed in order to fire in a case or shell holding a primer, (which produces the spark) a charge of propellant (gunpowder) and a projectile (bullets, slug or pellets.) Sometimes called "fixed ammunition" to differentiate from the individual components placed separately in muzzleloaders. A single unit of ammunition in modern firearms is called a cartridge. The units of measure for quantity of ammunition is rounds. There are hundreds of sizes of ammunition.

Diagram of a CartridgeDiagram of Ammunition RoundHandgun and Rifle Ammunition  Handgun and Rifle Ammunition

Antique Firearms

an·tique (ăn-tēk′) An antique (Latin: antiquus; "old", "ancient")

An antique firearm is a term to describe a firearm that was designed and manufactured prior to the beginning of the 20th century. Although the exact definition of what constitutes an "antique firearm" varies between countries, the advent of smokeless powder or the start of the Boer War are often used as cut-off dates.  Antique firearms are usually collected because of their historical interest and/or their monetary value. By U.S. federal definition, a firearm manufactured prior to 1899 or a firearm for which ammunition is not generally available or a firearm incapable of firing fixed ammunition.

Antique Pistols
Antique Pistols


















Aperture Sight

[′ap·ə‚chər ‚sīt]

An irregularly shaped adjustable mechanical item usually integral to a rear sight; it functions as a peephole through which the sight at the opposite end of a gun is brought into view in aiming at a target or object. An iron sight system of aligned markers used to assist in the aiming of a device such as a firearm, crossbow, or telescope that excludes the use of optics as in a scope. Also known as Peep Sights.

Aperture Sight
Aperture Sight


















AR 15 Rifle

The AR-15 comes in many sizes and has many options, depending on the manufacturer. The Colt AR-15 is a lightweight, 5.56 mm, magazine-fed, semi-automatic rifle, with a rotating-lock bolt, actuated by direct impingement gas operation or long/short stroke piston operation. It is manufactured with the extensive use of aluminum alloys and synthetic materials. The AR-15 was first built by ArmaLite as an assault rifle for the United States armed forces.

The AR-15 is a widely owned semi-automatic rifle. The AR does not stand for "Assualt Rifle" as many believe, it was named after the manufacturer that first built it, Armalite.














AR 15
  • The AR-15 is a lightweight, intermediate cartridge magazine-fed, air-cooled rifle with a rotating lock bolt, actuated by direct impingement gas-operation or long/short stroke piston operation. It has been produced in many different configurations, including semi-automatic.

  • AR does NOT stand for Assault Rifle, as is commonly believed. AR stands for the original company that manufactured it, ArmaLite. ArmaLite sold their rights to the AR-10 and AR-15 designs in 1959 to Colt.
Armor Piercing Ammunition

ar·mor (är′mər)

A type of ammunition designed to penetrate armor or armor-plated targets such as tanks, trucks, and other vehicles. An armor-piercing shell must withstand the shock of punching through armor plating. Shells designed for this purpose have a greatly strengthened case with a specially hardened and shaped nose, and a much smaller bursting charge. An armor-piercing (AP) shell is a type of ammunition designed to penetrate armor. From the 1860s to 1950s, a major application of armor-piercing projectiles was to defeat the thick armor carried on many warships. From the 1920s onwards, armor-piercing weapons were required for anti-tank missions. Furthermore it is used to defeat concrete, ballistic vests, bulletproof glass, and other defenses.

Armor Piercing Ammunition
Armor Piercing Ammunition



















ar·se·nal (är′sə-nəl)

A government establishment where firearms and ammunition are stored, repaired, or manufactured. The term is misused by the media to mean more than one firearm or any quantity of ammunition, as in "they found an arsenal."A governmental establishment for the storing, development, manufacturing, testing, or repairing of arms, ammunition, and other war materiel.


Over the centuries an Arsenal has included every variant of such a place, whether privately or publicly owned (with the latter in older royal and modern state-owned versions).

An Example of a Home Arsenal
An Example of what the News media would Call a Home Based Arsenal



















ar·til·ler·y (är-tĭl′ə-rē)

Large bore diameter (nominally 3" or greater) firearms designed to be operated by a crew of individuals. They are utilized to project explosive, armor defeating, incendiary, or nuclear projectiles over great distances. They are normally moved by vehicle because of their size and weight. "Cannon," mortars, howitzers, and similar are considered artillery.

Artillery is a weapon of war that operates by projection of munitions far beyond the effective range of personal weapons. Artillery comprise specialised devices which use some form of stored energy to operate, whether mechanical, chemical, or electromagnetic. Originally designed to breach fortifications, they have evolved from nearly static installations intended to reduce a single obstacle to highly mobile weapons of great flexibility in which now reposes the greater portion of a modern army's offensive capabilities.



















Assault Rifle

as·sault (ə-sôlt′)  ri`fle

An assault rifle is a selective fire (selective between automatic, semi-automatic, and burst fire) rifle that uses an intermediate cartridge and a detachable magazine. Assault rifles are the standard service rifles in most modern armies. Note; the difference between the assault rifle and the battle rifle. Assault rifles use smaller cartridges and are used at closer ranges than battlerifles. The larger sized rifle cartridges used in battle rifles make fully automatic fire more difficult.

Assault Rifles & Carbines
Assault Rifles & Carbines























































Assault Weapon

as·sault (ə-sôlt′)   weap·on (wĕp′ən)

Assault weapon is a political and legal term that refers to different types of firearms and weapons, and is a term that has differing meanings, usages and purposes.

In discussions about gun laws and gun politics in the United States, an assault weapon is most commonly defined as a semi-automatic firearm possessing certain cosmetic, ergonomic, orconstruction features similar to those of military firearms.

A political term with no fixed definition, being defined differently by different jurisdictions. Because the actual definition is so fluid, laws written to regulate assault weapons often define the term by various cosmetic characteristics which do not affect a firearm's power or function in any fundamental way. Despite public perception, assault weapons are not machine guns. They are semi-automatic firearms, not fully automatic firearms.

The term is distinct from the term assault rifle, which is a technical term with a specific meaning widely accepted both in law and within the military and firearms communities.

Assault Weapon Assault Weapon



  • A firearm with an automatic loading mechanism. A firearm that automatically loads the next cartridge to be fired into the chamber either upon the pull of the trigger in an open bolt design or upon the firing of the previous round in a close bolt design. Over time this term has been shortened to just "auto" and sometimes "automatic" thus creating confusion between a full-auto firearm and a semi-automatic firearm. An autoloader or auto-loader is a mechanical aid or replacement for the personnel that load ordnance into crew-served weapons, such as tanks and artillery. The term is generally only applied to larger weapons that would otherwisehave a dedicated person or persons loading them. Semi-automatic firearms are sometimes informally called "auto-loaders". However, this is a derivation of the term "auto-loading" rather than a physical "autoloader", as discussed here.

  • An autoloader, as its name suggests, extracts a shell and propellant charge from the ammunition storage rack/compartment and loads it into a magazine, if the gun has one, or directly into the chamber of the gun if it does not. It can and often does replace a human loader. 























Automatic Firearm

ȯd·ə¦mad·ik  ′fīr‚ärm

An automatic firearm is any firearm that will continue to fire so long as the trigger is pressed and held and there is ammunition in the magazine/chamber. While both "semi automatic" and"fully automatic" weapons are "automatic" in technical sense that the firearm automatically cycles between rounds with each trigger pull, under conventional usage a merely semi-automaticfirearm is not correctly referred to an "automatic weapon" or an "automatic firearm". The terms "automatic weapon" and "automatic firearm" are conventionally reserved to describe fullyautomatic firearms. Confusion can be avoided by this convention. A semi-automatic firearm fires one round with each individual trigger pull, while a fully automatic continuously fires roundswhilst the trigger is pressed and held.


The speed of fully automatic firearms is measured in rounds per minute (RPM) or rounds per second (RPS), in what is called the Rate of fire. The speed of fully automatic firearms iscompared to each other this way.


Glock 18 Machine PistolGlock 18 Machine Pistol                                                    HK mg4 light machine gunHK mg4 light machine gun 





















Anything that will safely stop a bullet and prevent it from hitting anything else after the target is struck.

Shooting Range Backstop
Shooting Range Backstop





















A handgun term. The rearmost surface of the grip. The rear of two gripstraps on a handgun, which lies beneath the heel of the hand when gripping the gun.

Handgun Backstrap
Handgun Backstrap


















Ball Ammunition

Originally a spherical projectile, now generally a fully jacketed bullet of cylindrical profile capped with a round nose.

Original Ball Ammunition Original Ball Ammunition                                                                  Modern Ball Ammunition Modern Ball Ammunition

Ballistic Fingerprint

A fired case has marks upon it that it picked up from the extractor, ejector, and breechface of the gun when the shot went off. A bullet fired through a rifled barrel also has rifling marks unique to the barrel that launched it. A record of these marks, when stored in a central database, is called a ballistic fingerprint. Some states require this record to be made by law, so that individual guns can be located from bullets or casings found at the scene of a crime.

Ballistic Fingerprint
Ballistic Fingerprint


The science of cartridge discharge and the bullet's flight. Internal ballistics deals with what happens inside of a firearm upon discharge. External ballistics is the study of a projectile's flight, and terminal ballistics is the study of the impact of a projectile.  science of projectiles. Interior ballistics deals with the propulsion and the motion of a projectile within a gun or firing device. Its problems include the ignition and burning of the propellant powder, the pressure produced by the expanding gases, the movement of the projectile through the bore, and the designing of the barrel to resist resulting stresses and strains.

Exterior ballistics is concerned with the motion of a projectile while in flight and includes the study not only of the flight path of bullets but also of bombs, rockets, and missiles. All projectiles traveling through the air are affected by wind, air resistance, and the force of gravity. These forces induce a curved path known as a trajectory. The trajectory varies with the weight and shape of the projectile, with its initial velocity, and with the angle at which it is fired. The general shape of a trajectory is that of a parabola. The total distance traveled by a projectile is known as its range.

Internal Ballistics - Ammunition Internal Ballistics - Ammunition   Terminal Ballistics Terminal Ballistics Bullet Flight Path Bullet Flight Path



The cylindrical metallic part of a gun which controls the initial direction of a projectile. A tube through which a bullet travels when a gun is fired

Gun Barrel (cut away)
Gun Barrel (cut away)



















[bat-uh-ree; French batuh-ree]

(In) Battery - A condition of a firearm where it is loaded, with the action closed, cocked and (with the possible exception of an engaged safety catch) ready to fire.


  1. Two or more pieces of artillery used for combined action.
  2. A tactical unit of artillery, usually consisting of six guns together with the artillerymen, equipment, etc., required to operate them.
  3. A parapet or fortification equipped with artillery.
Bayonet Lug

Bay·o·net Lug

(bā′ə-nĕt′, bā′ə-nĭt, -nĕt′ (lŭg)

A mounting point on a small arm that allows a bayonet or other accessory to be attached. A bayonet lug is a standard feature on most military muskets, rifles, and shotguns, and on some civilian longarms. It is intended for attaching a bayonet, which is typically a long spike or thrusting knife. The bayonet lug is the metal mount that either locks the bayonet onto the weapon or provides a base for the bayonet to rest against, so that when a bayonet thrust is made, the bayonet does not move or slip backwards.

Bayonet Lug
Bayonet Lug




















Beavertail pistol grip: the grip style used on the Colt 1911 handgun. A large piece of curved metal at the top of the grip which protects the user's hand from getting bitten by the hammer. It is nearly always the top part of the grip safety commonly found on many 1911-style pistols.

Beavertail on a 1911 style pistol
Beavertail on a 1911 style pistol


















Benchrest Shooting

noun bench·rest \ˈbench-ˌrest\

Benchrest shooting is a sport in which very accurate and precise rifles are shot at paper targets. The rifles ride on a front and rear rest, the rests may or may not be joined, depending on the rules of a particular competition. The rests sit on a table or bench, hence the name "benchrest. A shooting sport in which the competitors seek to place five or ten consecutive shots into the smallest possible group on a paper target at various ranges. All firing is done from an artificially supported shooting position. It is a severe test of the mechanical precision of both the small arm and its ammunition.

Benchrest Shooting
Benchrest Shooting




















On an outdoor shooting range, a large pile of dirt that functions as a backstop.

Berm for Target Shooting
Berm for Target Shooting


















Bevel Base

(bĕv′əl)   (bās)

Any bullet design in which there is a slight bevel (to facilitate cartridge reloading) between the base and the bearing surface proper. (Opposed to Plain Base)

Bevel Base Rifle BulletBevel Base Rifle BulletBevel Base Handgun BulletBevel Base Handgun Bullet


bi·ath·lon (bī-ăth′lən, -lŏn′)

A competition that combines events in cross-country skiing and rifle shooting. A shooting sport that combines both skiing and rifle shooting. It is the only shooting activity in the Winter Olympics. There is also a summer biathlon which involves running and shooting but it is not yet an Olympic event.

Biathlon Shooting
Biathlon Shooting















bi·pod (bī′pŏd′)

A stand having two legs, as for the support of an instrument or a weapon. A two legged support for the front end of a rifle to stabilize the gun while shooting.

Rifle with Bipod
Rifle with Bipod











Bird Shot

bird·shot (bûrd′shŏt′)

(Hunting) small pellets designed for shooting birds. Small lead shot for shotgun shells. A type of shotgun ammunition which uses very small pellets with individual projectiles of less than .24" in diameter designed to be discharged in quantity from the shotgun. The size of the shot is given as a number or letter--with the larger number the smaller the shot size. It is so named because it is most often used for hunting birds. The finest size generally used is #9 which is approximately .08" in diameter and the largest common size is #2 which is approximately .15"



















Black Powder

[¦blak ′pau̇d·ər]

The earliest type of firearms propellant that has generally been replaced by smokeless powder except for use in muzzleloaders and older breechloading guns that demand its lower pressure levels. An explosive mixture of saltpeter, charcoal, and sulfur, formerly used in firearms. An explosive propellant, which is obtained by carefully fragmenting and mixing potassium nitrate, charcoal, and sulfur in the proportions (by percentage weight) of 75:15:10.

Black powder is easily ignited and burns rapidly without air to form gases that are able to perform considerable mechanical work. It is one ofthe oldest explosives. No accurate date has been established for its invention.

Black Powder


















Blank Cartridge

blank′ car′tridge [blaŋk]  (kär′trĭj)

A gun cartridge with a charge of powder but no bullet. Ammunition which contains no projectile but which does contain a charge of low explosive, such as black powder, to produce a noise.

Blank Cartridge Blank Cartridge



A semi-automatic firearm whose breechblock and barrel are not mechanically locked together when fired. In such case the breechblock immediately begins to separate from the barrel upon firing. Blowback is used in comparatively low powered weapons, in which inertia of the breechblock, and cartridge wall adhesion against the chamber, are sufficient enough to retard opening until breech gas pressures have fallen to a safe level.

A type of action in an autoloading firearm where the breech is not locked. Rather, the recoil of the firing cartridge overcomes the inertia of a spring-loaded breechblock, forcing it back to cycle the action. A simple design, but limited to relatively low powered firearms---typically pistols of calibre .380ACP or less---or an impractically heavy breechblock would be required.

Gas BlowbackGas Blowback

blu·ing ˈblo͞oiNG/
  1. The chemical process of artificial oxidation (rusting) applied to gun parts so that the metal attains a dark blue or nearly black appearance.
  2. A controlled chemical rust process that produces a very dark, almost black, blue finish to the steel parts of a firearm which enhances the appearance and provides some protection from unwanted rust. Sometimes it can have a slight brownish undertone. The percentage of blue finish remaining on a gun can be a proxy for describing its condition.

Boat Tail


  1. A type of bullet, tapered at the rear in order to decrease turbulence in flight and increase accuracy. More prevalent in target rather than hunting bullets.
  2. A type of projectile that has a tapered base (rear end) that reduces the drag from the air as it travels to its target.


  1. The mechanism of some firearms that holds the cartridge in place during the firing process. It must be moved out of the way to load and unload the gun; this action may be manually performed by the shooter pulling back on an exterior knob called the bolt handle and then sending it forward again, or the action may be performed by other moving parts within the firearm. When the user must move the bolt manually, the firearm is called a bolt-action firearm.

2. A cylindrical shaft, controlled by an attached lever, which rotates a partial revolution engaging locking lugs in complementary recesses, contains an internal spring-loaded firing pin, and becomes the breech-block of a bolt-action firearm.

Bolt Action

[bohlt-ak-shuh n]

  • An action type, most frequently used on rifles, perfected by Peter Paul Mauser in 1898, whereby a cylindrical shaft, controlled by an attached lever, manually feeds a cartridge into the chamber, rotates a partial revolution engaging locking lugs in complementary recesses in the front receiver ring, allows firing by the fall of an internal spring-loaded pin, opening, extraction, re-cocking and ejection with the same lever in preparation for the next shot.
  • A type of firearm, almost always a rifle, in which an empty shell casing is removed from the firing chamber by the turning and retraction of a metal cylinder shaped mechanism called a bolt. A new, un-fired, cartridge is inserted and secured into the chamber by reversing the action of the bolt.
Bolt Stop
  • A displace-able flange, usually towards the rear of a bolt action firearm which in normal position, either detented or under spring tension, prevents the bolt from falling completely out the rear when cycling the action. It is readily moved aside by the bolt stop release to allow removal of the bolt for cleaning or disassembly.
Bolted Safety
  • A secondary catch on the safety, often seen on big-bore double rifles, designed to prevent its inadvertent disengagement by a careless gunbearer

[bawr, bohr]

  • The inside surface of a firearm's barrel. British term for Gauge
  • The hollow portion of a barrel through which the bullet travels during it's acceleration phase.
  • A smooth-bore firearm is one that does not have rifling on the barrel's internal surface.
  • A big-bore firearm is one that fires a large caliber.
  • A small-bore firearm is one that fires a small caliber.
Bore Diameter

[bawr, bohr]    [dahy-am-i-ter]

  • The diameter of the inside of the barrel after boring, but before rifling.
Bore Sight

[bawr-sahyt, bohr-]

  • A process by which sights are adjusted to converge on the same line as the bore. Accomplished by placing a rifle in a rest, sighting down the open bore on a prominent distant point at an appropriate range, then aligning the sights to superimpose on the same point. Alternatively, may be accomplished with a device known as a collimator. The process should conserve ammunition when sighting-in a rifle by approaching proper sight adjustment before actually firing the rifle with live ammunition.


  • A type of cartridge with a pronounced shoulder between the body of the case and the mouth---where the bullet diameter is noticeably less than the case diameter, allowing a larger powder capacity than would otherwise be possible in an altogether more cylindrical case, and to provide a datum point to establish correct headspace.


  • A cartridge case having a primer pocket with one central touchhole at the center bottom. A tiny anvil is built into the primer to provide a surface against which the detonating compound may be sharply pinched by the action of the firing pin. Most commonly used in the USA today. It is simple to remove the spent Boxer primer for re-loading the shell casing with a single, central, pin-shaped decapping punch.
  • A type of action (receiver) for a break-open gun where the lockwork is contained within a box-shaped housing. (see also: Sidelock). A boxlock is superior to a sidelock because although more metal needs to be removed from the action body, less wood needs be removed from the head of the stock---and wood is generally more vulnerable than metal. The Anson & Deeley boxlock, patented in 1875, the simplest, most reliable and most successful action design, is identified by two pins spanning the width of the action, one at the bottom rear and one slightly forward and higher, upon which the sears and hammers, respectively, rotate.
  • Black Powder Express. A cartridge "as powerful as an express train."

[bras, brahs]

  • An alloy of approximately 2 parts copper and 1 part zinc, which because of its combination of strength and ductility, is commonly used for making cartridge cases, which fit easily into the chamber of a firearm and then when discharged, expand to seal the breech. Also, slang for cartridge cases.
  • A slang term for an empty shell casing. Most shell casings are made of the metal alloy known as brass.

[noun breech; verb breech, brich]

  • The end of a barrel where the powder charge is ignited; the end closest to the shooter
  • That portion of the gun that contains the rear chamber portion of the barrel. The rearmost end of a barrel, closest to the shooter.
Breech Block


  • A moveable block of steel, sliding in a mortised raceway, or rotating on a hingepin, that seals the breech of a cartridge firearm and through which the firing pin passes to detonate the primer.
Breech Face
  • The flat, normally-vertically-oriented steel wall through which the firing pin passes and which supports the base of a cartridge when it is fired
  • That portion of the breech block which touches the cartridge when the breech is closed.
Breech Loading Gun Breechloader


  • A firearm that is loaded from the breech end of the barrel, usually with a cartridge (as opposed to a muzzle-loader).
  • A firearm in which the cartridge or shell is inserted or loaded into a chamber to the rear portion of a barrel.
Breech Opening
  • The open rear of the barrel through which cartridges are inserted into the chamber.  


  • A box of ammunition roughly equal in size and weight to a brick. Most often used to describe a 500-round container of 22 Long Rifle ammunition.


  • A small secondary plate, mounted behind and parallel to a sidelock gun's lockplate which supports the inside ends of the pins about which the moving parts rotate
Broadway Rib

[brawd-wey]   [rib]

  • Browning term for a particularly wide rib for their over & under target guns.


  • An oxidation process applied to the surface of raw steel, undertaken with acids, to produce a finish that resists further rusting, providing as you might expect a brownish color, allowing the pattern of damascus barrels to show through. Popular in the 19th century and with people today desirous of evoking that time.
Browning John Moses
  • The world's greatest firearms inventor. Born in Ogden, Utah. While he made some guns himself, normally, he licensed his designs to prominent manufacturers such as Colt, Fabrique National and Winchester. While Samuel Colt and Paul Mauser achieved fame basically as a result of one idea, John M. Browning produced dozens of the most successful firearms designs, including the Winchester 1885, 1886, 1892, 1894 and 1895 rifles; The Colt 1903, 1908, 1911 and Woodsman pistols; the Browning Auto-5 and Superposed shotguns; as well as the BAR, 1917 and M2 .50 calibre machine guns.
BT or Beavertail Forend
  • A broad forend, wrapping partially around the barrel(s) to give a more positive grip and to better protect the hand from hot barrels than does a splinter forend.
Buckhorn Sight

/ˈbʌkˌhɔːn/   [sahyt]  

  • A rear barrel iron sight, normally used on rifles, where the open-topped viewport is formed by a pair of symmetrical crescents. Rocky Mountain sight.
Bulino Engraving


  • Shallow, pictorial engraving designs, often of photographic quality, executed directly by hand onto the steel with a fine-pointed scribe called a burin, without the use of a chasing hammer. Also called banknote engraving. Often seen on high-grade, contemporary Italian shotguns.
Bull Barrel

[boo l]  [bar-uh l]

  • A general term for a large-diameter, heavy, rifle barrel, used for target or varmint shooting.
  • "Bull barrels" are barrels that are not tapered at all. These very heavy barrels, designed for extreme accuracy, are usually seen on target rifles.

noun, bul·let often attributive  (bo͝ol′ĭt)

A small piece of metal or another material that is shot out of a gun. A usually metal projectile in the shape of a pointed cylinder or a ball that is expelled from a firearm, especially a rifle or handgun.

Diagram of a Cartridge Diagram of a Cartridge                                                      Bullets Bullets

Bullet Mold
  • A hand tool, in the general shape of a pair of pliers, with a two-part cavity of specific dimension at the working end, into which is poured molten lead in order to cast a bullet for a specific firearm. Normally affixed with a sprue-cutter to trim the excess lead from the bullet.
Bullet Proof Vest
  • A popular but incorrect term for bullet resistant clothing.
Bullet Starter
  • A tool fitted with a concentric plunger used for starting a bullet on a balanced path into the bore of a rifle from the muzzle. Often used in conjunction with a false muzzle built for the specific rifle.
Bullet Trap
  • A type of backstop that catches the fired bullet and prevents it from exiting the area. Bullet traps are most commonly used on indoor ranges.
  • A rifle configuration in which the action and magazine are located behind the trigger. This makes the overall length of the firearm shorter than it otherwise would be.
Burgess Front Sight
  • An excellent easily retractable front sight blade, designed and built by gunsmith Tom Burgess.
Burgess Mounts
  • An excellent quick-detachable scope mounting system, designed and built by gunsmith Tom Burgess. Operated by turning locking levers a detented 90 degrees.


  • Burnish (v) - To smooth a (steel) surface to a mirror finish by firmly rubbing with a hard, polished steel tool, compressing unevenness in the surface.

Bushed Firing Pins
  • Circular steel fittings, about 1/2 inch in diameter, screwed into the breech face of a gun and through which the firing pins pass. Firing pin bushings allow the convenient replacement of broken firing pins. They also allow the renewal of an older gun where, over the decades, leakage of high-pressure gas from corrosive primers has eroded the breech face around the firing pins. In British: Disk-set strikers


  • The end of a gun stock; the part that rests on the shoulder when the gun is mounted.
  • A fixed-position shooting station for British-style driven bird shooting, often rock-lined and partially underground, providing some effect of a blind for the shooter (the Gun) and his loader.
  • The base of the grip on a handgun and the rearmost portion of the stock on a long gun that braces against the shoulder.


  • A plate made usually of metal and attached to the butt end of a gun stock

  • A plate made of some material harder than the wood of the buttstock, fitted to the end of same to protect it. It may be made of hardrubber, horn, plastic or steel. It may be shaped relatively flat like a Winchester "Shotgun" butt on a rifle, like a crescent, or with all manner of protruding appendages in the interest of achieving consistency of mounting position as in a Swiss or scheutzen buttplate. It may be finished smooth, checkered, striated or engraved.
C Fastener
  • Westley Richards' proprietary toplever-actuated bolting system for break-open guns and rifles, whereby the toplever, when pushed to the right, cams against a facet on the top of the action body and withdraws the locking bolts rearward from their respective bites.
C Ring
  • An internal web machined in the front receiver ring of a Mauser Model 98 and of all the proper copies of this famous action. Not only does this internal ring provide additional strength to the receiver at its most stress-bearing point, this essential part of the design provides a stop for the barrel when screwed into the receiver, allowing positive control of headspace. Because there is a cut-out for the bolt's claw extractor, it appears in the form of a "C" when viewed from the loading ramp. Being difficult to machine, lesser actions' front receiver rings are simply bored straight through.
Cable Lock
  • A cable with a padlock at the end. It is threaded through the action of the firearm.
Cal or Caliber
  • System of measurement for the internal bore diameter of a rifled-barreled firearm (rifle or pistol) based on the decimal part of an inch. For example, .25 calibre and .250 calibre both signify a bore size of 1/4 inch. American calibre designations refer to the distance from land to land, not groove to groove. Ammunition companies' marketing departments occasionally take liberties with exact measurements. For example, a .270 Winchester bullet actually measures .277 inch in diameter.


  • The diameter of the bore of a gun taken as a unit of measurement.

  • The diameter of the bore of a firearm measured as a fraction of an inch. Although such a measurement may be frequently stated in millimeters. It is correctly expressed as ".40 caliber" (note the decimal point) or as "10 millimeter" (without "caliber" or the leading decimal point). Caliber numbers when used to identify the size of the bullet a gun will file are usually followed by words or letters to create the complete name of the cartridge. These letters often represent a brand name or an abbreviation for the name of the company that first introduced the round.
Call Bead
  • A flat gold or brass disc, mounted into the face of a front sight, seen as a crisp circle.
Camp Perry

[kamp]  [per-ee]

  • National Guard facility near Port Clinton, Ohio containing the largest rifle range in the world. Site, since 1912 of the NRA's national rifle matches. Also, in its honor, the name of a model of Colt .22LR calibre single shot target pistol.
  • Slang term for a firearm sound suppressor.

[kan-l-oo r]

  • A crimped or knurled groove, rolled onto a bullet or the neck of a cartridge case, to help retain a bullet in its case, and/or to provide a space for bullet lubricant.
  • A groove or indention around the circumference of a bullet. Its purpose is to permit the cartridge casing to be crimped tightly against the bullet shank to hold it firmly to the casing. A groove or indention around the circumference of a bullet. Its purpose is to permit the cartridge casing to be crimped tightly against the bullet shank to hold it firmly to the casing.


  • To tilt a gun to one side or the other, complicating sighting considerably. Can cause material loss of accuracy, particularly with a rifle at longer ranges. Some better long range target rifles are equipped with Spirit Level sights to help the marksman control canting.
  • Tilting the firearm slightly to one side, so the grip is no longer vertical in relation to the ground. Canting the firearm can make precision shooting more difficult, but may be necessary in some circumstances.


  • A percussion cap; a separate primer; fit over the tip of the nipple of a muzzle-loading percussion-actioned firearm.
Cape Gun
  • A two-barreled, side-by-side, shoulder-fired gun having one smoothbore shotgun barrel and one rifled barrel.
Capper De Capper
  • A hand tool used in the field for inserting live and removing spent primers from cartridges.
Captive Ramrod

[kap-tiv]   ˈramˌräd/

  • A rod, for loading and/or cleaning a muzzle-loading firearm (usually a pistol) that is permanently connected to the gun by some sort of swivel, so as to be utilized easily, but never lost.

[kahr-been, -bahyn]  

  • A rifle with a relatively short barrel. Any rifle or carbine with a barrel less than 16" long must be registered with the Bureau of Alcohol, Tobacco and Firearms. Shotguns with barrels less than 18" long fall into the same category. Commonly used today to indicate any rifle of short overall length.

  • A general term referring to relatively short-barreled, quick-handling rifle, often intended for use on horseback.

  • In Winchester lever-action terminology, a carbine has a single barrel band.  In German, a Stutzen.


  • A mark within a border. On an American military rifle it is typically stamped into the wood and shows the initials of the name of the accepting inspector and often, the date he accepted the firearm into service. Notable gun makers have used the concept by stamping their mark onto a bit of precious metal in a small recess in the steel.


  • In its definition valid from circa 1870 to the present:  a small usually cylindrical packet, containing a detonating primer, a powder charge, a load---either a single projectile for a rifle or a quantity of small pellets for a shotgun---and possibly some attendant wadding. The cartridge is placed into the breech of a firearm, comprising all required consumables for the firing of the weapon.
  • A single, complete round of ammunition which includes the case, primer, powder, and bullet
Cartridge Trap
  • A compartment built into the buttstock of a long gun, usually with a hinged cover, in which are drilled holes deep enough to hold several spare cartridges of the type suitable for use in the specific gun
Case or Casing


  • The envelope (container) of a cartridge. For rifles and handguns it is usually of brass or other metal; for shotguns it is usually of paper or plastic with a metal head and is more often called a "shell."
Casehardening Colors


  • Mottled blue/green/brown colors on a shotgun or double rifle receiver, vintage Winchester receiver or Colt Single Action frame. The colors are the by-product of a heat-treating process that incorporates carbon into the surface molecular structure of the steel, providing a hard-wearing surface without making the entire receiver brittle. The parts to be casehardened are packed in a crucible with carbon-rich media such as bone meal and charcoal, heated to bright orange, about 1800°F, then quenched in bubbling oil. Also called Carbonizing. The colors themselves are fairly perishable both from wear and from sunlight. The percentage of original case colors remaining is therefore a quick proxy for the cosmetic condition of the gun.


Guns should never be rehardened in the vain interest of restoring the cosmetic effect of the colors. Casehardening is a heat process which alters the surface molecular structure of the steel. Rehardening an action can warp it. Subsequent efforts to straighten the metalwork, either by bending or filing can only harm the fine original metal-to-metal fit and adversely alter the workings of carefully aligned internal parts.

Cast Off
  • An offset of a gun stock to the right, so that the line of sight aligns comfortably with the right eye while the butt of the stock rests comfortably on the right shoulder. Almost all right-handed shooters benefit from a little castoff and most custom built guns are made this way. The only question is how much. The castoff of a gun is about right when, with the gun comfortably mounted, the front bead lines up with the center of the standing breech. A stock offset to the left, for shooting from the left shoulder is said to be Cast On.
Center Fire

Center Fire (Cartridge)

  • A cartridge with its primer located in the center of the base of the case.
  • A cartridge with a separate removable/replaceable detonating primer pressed into the center of its base---as opposed to a rimfire cartridge.
Center Of Mass
  • For self-defensive shooters, COM represents the area of an attackers torso within which the most vital organs are likely to be disrupted by a gunshot. Shooting to COM is considered the most expedient way to stop an assailant from continuing threatening behavior.
Centerfire Cartridge
  • A cartridge with a separate removable/replaceable detonating primer pressed into the center of its base---as opposed to a rimfire cartridge.
  • An area at the breech end of a barrel, of about the diameter of the cartridge for which the gun was intended, and into which the cartridge is inserted. The nominal length of a shotgun chamber will accommodate the loaded cartridge for which it was intended and allow for its crimp to open fully when the cartridge is fired. Although one can easily insert a longer-than-nominal-length loaded cartridge in a shotgun chamber, it is not advisable to do so because when it is fired the crimp will open into the forcing cone. Because of the taper of the forcing cone, the crimp will not be able to open fully and the gun will develop far greater pressure than it was designed to handle.
  • The rear part of the barrel that is formed to accept the cartridge to be fired. A revolver employs a multi-chambered rotating cylinder separated from the stationary barrel.
Chamber Cast
  • To pour a low-melting-point material such as "Cerrosafe" into the chamber of a firearm, let it just cool, knock out the plug and measure it with a micrometer against published dimensional specifications to determine the chambering of a possibly-unmarked or possibly-altered firearm.
Chamber Depth Gauge
  • A cylindrical plug of hardened steel, precisely machined in relation to the standard dimensional specifications of a given cartridge, engraved with circumferential lines demarking the different typical lengths of cartridges available for that bore. By inserting the appropriate bore's plug-gauge into the chamber, one can read off the line indicating the nominal maximum length of the cartridge which should safely be able to be shot from that gun (provided, of course, the gun be in sound condition).
Chamber Throat

[cheym-ber]  [throht]

  • This is the area in the barrel that is directly forward of the chamber, which tapers to the bore diameter.
  • A simple, disposable narrow spring-lined channel-rail in which cartridges are supplied for military weapons. The shooter positions the clip vertically above the firearm's internal magazine, then pressing down with the thumb, slides the cartridges from the charger and down into the magazine..
  • A device typically made from stamped metal which holds a group of cartridges for easy and virtually simultaneous loading into the fixed magazine of a firearm.
  • A simple, disposable narrow spring-lined channel-rail in which cartridges are supplied for military weapons. The shooter positions the clip vertically above the firearm's internal magazine, then pressing down with the thumb, slides the cartridges from the charger and down into the magazine.
Checkered Butt
  • Checkering, applied to the otherwise-unfinished butt end of a gunstock
  • A regular pattern of fine grooves cut into the surface of a stock to aid in gripping a gun. Originally done for utility only, checkering has become an art form in itself; craftsmen adorning the borders with ribbons, fleur-de-lys, floral carving, etc. The amount of coverage, the precise regularity, and the number of lines per inch indicate the quality of the work. Too-fine checkering, however, defeats the purpose of the work altogether.


  • A broad, flat, raised area on the side of a buttstock. While considered a sign of a well-appointed gun, it actually may interfere with natural mounting and pointing---somewhat negating the positive effect of cast-off. The cheekpiece is carved on the left side of a stock for a right-handed shooter; it is on the right side for a left-handed shooter.
  • A rotary machine-tool cutting bit, in the precise shape of a specific bullet. Used for cutting the internal cavity of a bullet mold.


  • A constriction at or near the muzzle of a shotgun barrel that affects shot dispersion.
  • A carefully measured constriction of the bore of a shotgun at the muzzle, designed to control the spread of the shot as it leaves the barrel
Choke Tubes
  • Short, interchangeable cylinders, of subtly different internal tapers, that screw into a threaded recess at the muzzle of a shotgun. By inserting different choke tubes, one can alter the shot pattern thrown by the gun. Choke tubes should be tightened until snug. Guns fitted for choke tubes should never be fired without tubes in place.

(krŏn′ə-grăf′, krō′nə-)

  • An device with a set of sensors through which a bullet is made to pass, connected to an electronic instrument which calculates bullet velocity.


Churchill Rib
  • A relatively tall, narrow, matted, solid, top rib on a pair of side-by-side barrels, developed by Robert Churchill.
Claw Extractor


  • An essential design element of the Mauser 98 bolt action and its derivatives: the Springfield '03 and the Winchester pre-'64 Model 70. A large, long extractor is mounted to and revolves around the bolt shaft---or more properly, remains stationary in the receiver raceway when the bolt revolves. This claw takes positive hold of the cartridge coming from the magazine and places it in the chamber when the bolt is closed. Then, when the bolt is opened, the claw, never having relinquished its grip on the rim of the cartridge, withdraws it from the chamber with absolute reliability. Lesser bolt actions have a small clip built into the bolt face which snaps over the chambered cartridge rim when the bolt is closed. While cheaper to manufacture, this system allows the possibility of the clip slipping back off the rim of the expanded spent case during extraction. Most experienced hunters prefer an action with a Mauser-type claw extractor for its reliability, especially when facing dangerous game.
Claw Mounts
  • A quick-detachable scope mounting system, popular in Germany and Austria. The front of the scope is fitted with a hook-shaped tentacle which is inserted into a slot in a fixed front scope base. The rear of the scope is fitted with another set of hook-shaped tentacles. When these are pressed sharply downwards into their opposing receptacles they snap into place, held by a spring-loaded clasp, locking the scope into position. When properly installed, claw mounts are generally considered the best quick-detachable system for scope mounting: the cleanest looking, the easiest to operate and the most accurate in returning to zero. But, it is not an off-the-shelf, bolt-on system; claw mounts must be custom-fitted by a skilled gunsmith
Clay Pigeon

[pij-uh n]

  • Originally, live pigeons were used as targets, but they were gradually replaced with clay disks and ultimately banned. Later clay has been replaced with more suitable raw materials.


  • Unloading a gun and double checking that it is unloaded or fixing a malfunction so that the gun is ready to fire again.


  • A unit of adjustment for a sight. Can be for Iron sights, Reflex Sights and Scopes




A device for holding cartridges together, usually to facilitate loading. Widely used as a synonym for "magazine" (although most firearm authorities consider this substandard usage). Technically, a magazine has a feeding spring, a clip does not. A clip is a device that is used to store multiple rounds of ammunition together as a unit, ready for insertion into the magazine or cylinder of a firearm. This speeds up the process of loading and reloading the firearm as several rounds can be loaded at once, rather than one round being loaded at a time

Gun Magazine vs Clips
Gun Magazine vs Clips


















  • A simple, disposable narrow spring-lined channel-rail in which cartridges are supplied for military weapons. The shooter positions the clip vertically above the firearm's magazine, then pressing down with the thumb, slides the cartridges from the clip and down into the magazine. (Stripper Clip)
Closed Bolt Firing System
  • A type of firearm in which the action is closed, with a cartridge in the chamber prior to firing. When the trigger is pressed the cartridge is fired, and the action cycles loading another cartridge into chamber and when firing is stopped the bolt remains closed and the chamber remains loaded.
Co Witness Sighting

[wit-nis]  [sahyt]  

  • The use of any iron sight mounted onto a rifle that is fitted with an optical sight as a primary sighting system. They come in two basic configurations, fixed or flip-up. The idea is that if you align your red dot and your iron sights you have a backup aiming system on the gun


  • A firearm's exposed hammer.
  • To tension the mainspring of a gun in preparation for firing, such as by pulling back the external hammer, pulling back the slide of a pistol, or opening and closing the barrel(s) of a break-open gun.
  • The term referring to the action of manually drawing the hammer back against its spring until it becomes latched against the sear, or sometimes the trigger itself, arming the hammer to be released by a subsequent pull of the trigger. Some external hammers, and all internal hammers, may be cocked simply by pulling the trigger
Cocked And Locked
  • The practice of carrying a self-loading pistol with a round in the chamber, the hammer cocked and the safety engaged. (CONDITION ONE)
  • Proper condition for active carrying of a Colt 1911 pistol: a round in the chamber, the hammer cocked, and the thumb safety engaged. Somewhat unnerving to the uninitiated.
  • A state of readiness of a firearm. The hammer (or similar mechanism if there is no hammer) only needs to be released by the trigger to cause the gun to fire.
Cocked and Locked
Cocked and Locked


















Cocker And De-Cocker
  • A type of action on a break-open gun or rifle where, in place of a traditional top tang safety, a somewhat more robust tab is fitted. Normally such a gun is carried in the field loaded, but with the action not cocked---an exceedingly safe condition. Then, when ready to fire, the shooter, instead of pushing a safety tab forward, pushes this larger tab forward, cocking the mainspring, making the gun ready to fire. Then, if the shot is not taken, he may simply slide this tab rearwards again, de-cocking the gun and returning it to the still-loaded, but very safe position. Or, in German: Handspanner.
Cocking Indicators
  • Small devices attached to the internal hammers of a break-open gun and visible from the exterior of the gun to show when each lock is cocked and when it has been fired. These are usually in the form of protruding pins on a boxlock gun or in the form of engraved or gold inlaid lines on the tumbler pins of a sidelock gun
Coin Finish
  • Generally refers to a high-polish finish, bright steel on the receiver of a break-open gun. Other action-body finishes could be case-hardened, blued or French-gray (a chemical-finish, dull gray steel color). Coin-finish, when appearing typically on a modern, high grade Italian shotgun shows off the exquisite and delicate engraving better than other finishes. The term is sometimes used (incorrectly) by people dealing in old guns to describe the finish on a well-worn gun’s receiver when all the original case-hardening colors have worn or have been polished off.
Cold Clean Bore
  • The first shot from a rifle that has been cleaned, and not fired recently may go to a different point of impact, for the same point of aim than a rifle that has been fired recently. This first shot is referred to as a shot from a cold, clean, bore.
Cold Range
  • Pistol and or any firearm must be unloaded until it is your turn to shoot
Collapsible Stock

or collapsable [kuh-lap-suh-buh l]

  • A stock on a long gun that can be shoved into itself to shorten it, either for storage or to make the gun fit shooters of different sizes.


  • An optical device, mounted to the muzzle of a rifle via a bore-sized mandrel, the purpose of which is to allow a reasonable approximation of correct sight adjustment before actually firing live ammunition
  • The top of a gun's stock, where a shooter rests his cheek when mounting a gun. As it is the top of the stock that determines the position of one's eye, and one's eye is the rear sight on a shotgun, the position of the comb is very important in determining the proper fit of a shotgun.
Combination Gun
  • A firearm with various different configurations of rifle and shotgun barrels. See various specific types: BockbüchesflinteCape GunParadox,  DrillingDoppelbuches-DrillingVierling,

 (kə-mĕm′ər-ə-tĭv, -ə-rā′-)

  • In firearms parlance, a gun that was manufactured in "limited" numbers (often into the thousands), marked, stamped or fitted with extra bells and whistles in such a way as to evoke reverence to some famous person, place or historical event. Rather than to be manufactured for honest use, a commemorative is manufactured specifically to be collected. Actually to shoot one will normally delete any supposed extra value such a questionable concept ever had in the first place.

[kom-puh n-seyt]

  • Also call a Muzzle Brake. A device attached to or made as part of a firearms barrel designed to reduce recoil or muzzle movement on firing. They generally increase muzzle blast. The may also, but not necessarily so, diminish muzzle flash.
  • A cylindrical muzzle extension, with slots on the top, designed to push the muzzle down when a gun is fired, counteracting its tendency to rise



[kuh n-seel]

  • verb (used with object) to hide; withdraw or remove from observation; cover or keep from sight: He concealed the gun under his coat.
  • Hidden from view. A handgun is concealed when it is carried in such a manner that is unseen


Concealed Third Fastener
  • An extension protruding rearward from the breech end of a set of side-by-side barrels and entering a complementary recess in the breech face. The top of the extension is locked down by a cam attached to the toplever spindle. When the gun is closed this extra fastener is not visible from the exterior of the gun. Also called a Secret Bite.
Condition One

Condition One, etc

(kən-dĭsh′ən)   (wŭn)

A system devised by Jeff Cooper for enumerating carry modes for the Colt 1911 and similar auto pistols. Condition One is cocked and locked; Condition Two is hammer down with a round in the chamber; Condition Three is with a loaded magazine, empty chamber; Condition Zero is with a round in the chamber, hammer cocked, safety disengaged.

Colt Delta Elite
Colt Delta Elite


















Controlled Feed
  • Aspect of the design of the Mauser 98 bolt action and its derivatives: the Springfield '03 and the Winchester pre-'64 Model 70. A large, long extractor is mounted to and revolves around the bolt shaft---or more properly, remains stationary in the receiver raceway when the bolt revolves. This claw takes positive hold of the cartridge coming from the magazine and places it in the chamber when the bolt is closed. Then, when the bolt is opened, the claw, never having relinquished its grip on the rim of the cartridge, withdraws it from the chamber with absolute reliability. Lesser bolt actions have a small clip built into the bolt face which snaps over the chambered cartridge rim when the bolt is closed. While cheaper to manufacture, this system allows the possibility of the clip slipping back off the rim of the expanded spent case during extraction. Most experienced hunters prefer an action with a Mauser-type claw extractor for its reliability, especially when facing dangerous game.
Controlled Pair
  • Two shots fired in rapid succession. It is different from a double tap because in a controlled pair, the second shot will be fired after the shooter has obtained a second sight picture, whereas in a double tap both shots are fired based upon the initial sight picture alone.


  • An early form of smokeless powder, developed in England in the late 1880s, taking the physical form of little strings---or cords. Unlike black powder which preceded it, it burned a bit more slowly, enabling pressure to build in a barrel more evenly, increasing the duration of the motive force, increasing its efficiency propelling the projectile down the bore to higher velocities. And, it didn't generate nearly as much smoke---which hitherto both obscured the vision of the shooter while revealing his position to an adversary.
Counterbored Cylinder
  • In Smith & Wesson parlance, Recessed

[kuhv-er] verb

  • To protect or conceal
  • Take cover, to seek shelter or safety
  • Anything an intended victim hides behind that will probably stop a bullet.
Cover Garment
  • Any piece of clothing that covers the holstered gun. When the gun is worn on the belt, the most common types of cover garments are vests, sweaters, and jackets.
Cowboy Action Shooting

[kou-boi] [ak-shuh n] [shoot]

Cowboy Action Shooting (CAS, also known as Western Action Shooting, Single Action Shooting, or Cowboy 3-Gun) is a competitive shooting sport that originated in Southern California, US, in the early 1980s. Cowboy action shooting is now practiced in many places with several sanctioning organizations including the Single Action Shooting Society (SASS), Western Action Shootists Association (WASA), and National Congress of Old West Shooters (NCOWS), as well as others in the US and in other countries.

CAS is a type of multi-gun match utilizing a combination of pistol(s), rifle, and/or shotgun in a variety of "old west themed" courses of fire for time and accuracy. Participants must dress in appropriate theme or era "costume" as well as use gear and accessories as mandated by the respective sanctioning group rules.



The swinging unit that hinges the cylinder of a revolver with the frame.

Revolver Crane
Revolver Crane











  • Site, from 1872 until 1912, in Queens, Long Island, of the National Rifle Association's first national matches. Name used by several rifle makers to invoke the concept of accuracy in their products.
  • Sloppy, indeterminate movement of a trigger before the actual point of let-off.
Crescent Buttplate
  • A sturdy, cast metal buttplate fitted particularly to many early lever-action rifles with a deep curve in the center of the butt, durable under rough use, but uncomfortable in use and extremely painful when carelessly mounting and firing a powerful rifle.
  • The star-shaped folded closure at the mouth of a shotgun shell. The nominal length of the cartridge is measured with the crimp open---for which the gun's chamber must be long enough to accommodate
Cross Dominant
  • This means a shooter who is right-handed but left-eyed, or left-handed and right-eyed.
Cross Eyed or Crossover Stock
  • A gunstock with extreme cast (Cast-off or Cast-on), usually custom made, for use by persons with disability so as to be able to shoot from the right shoulder using the left eye (or from the left shoulder using the right eye). Or, for a right-handed shooter with a left master eye.
Cross Pin Fastener
  • A horizontal wedge, press-fit through the forend of a vintage gun, through a lump attached to the underside of the barrel and out the other side of the forend. To secure the forend in position. Also called a key fastener.


  • A steel bolt, mounted transversely through a rifle stock just under and behind the front (and sometimes rear) receiver ring, sometimes concealed in the wood and usually against which the action is carefully bedded. When properly fitted, it helps distribute the recoil and reinforces stock at the point where wood has been removed to accept the action. Recoil crossbolts can be recognized by the flush-mounted circular steel fittings on the side of the stock, but are sometimes finished with contrasting wooden plugs and sometimes concealed completely. Also called Reinforcing Crossbolt.


  • The cross-shaped object seen in the center of a firearm scope. Its more-proper name is reticle.
  • Basic form of telescopic sight reticle, having one fine vertical line and one fine horizontal line with which to establish the point of aim.
  • The area inside the bore nearest the muzzle. Damage to the crown can severely and adversely affect the firearm's accuracy.
  • The finish contour of the muzzle of a rifle. May be flat or rounded. Often shows effective chamfering to protect the critical rifling at the absolute end of the muzzle


Copper Units of Pressure. The units by which cartridge breech pressures are measured through compression of a copper crusher gauge. Similar but not identical to the older pounds per square inch (psi) system of measurement. Copper units of pressure or CUP, and the related lead units of pressure or LUP, are terms applied to pressure measurements used in the field of internal ballistics for the estimation of chamber pressures in firearms.

C.U.P. vs PSI C.U.P. vs PSI                                                                         Copper Units of Pressure Copper Units of Pressure

Curios or Relics
  • Is defined in 27 CFR 178.11 as follows:"Firearms which are of special interest to collectors by reason of some quality other than is associated with firearms intended for sporting use or as offensive or defensive weapons. To be recognized as curios or relics, firearms must fall within one of the following categories:
    1. Firearms which were manufactured at least 50 years prior to the current date, but not including replicas thereof;
    2. Firearms which are certified by the curator of a municipal, State, or Federal museum which exhibits firearms to be curios or relics of museum interest; and
    3. Any other firearms which derive a substantial part of their monetary value from the fact that they are novel, rare, bizarre, or because of their association with some historical figure, period, or event. Proof of qualification of a particular firearm under this category may be established by evidence of present value and evidence that like firearms are not available except as collector's items, or that the value of like firearms available in ordinary channels is substantially less."
A list of acknowledged "Curios or Relics" is available from the Bureau of Alcohol, Tobacco and Firearms, Firearms Technology Branch, Room 6450, 650 Massachusetts Avenue NW, Washington, DC 20226

A special Curios or Relics license is available from the BATF, which allows collectors to buy eligible firearms in interstate commerce. A licensed collector is not authorized to engage in business as a dealer in any firearms, including curios or relics.

Cut Away
  • A firearm that has had numerous careful machining cuts taken in its exterior with a view to exposing and demonstrating the functioning of critical parts of its mechanism
Cutts Compensator
  • A cylindrical muzzle extension, with slots on the top, designed to push the muzzle down when a gun is fired, counteracting its tendency to rise.


  • That part of a modern revolver that holds cartridges in separate chambers radially around a central hingepin. The cylinder revolves as the handgun is cocked, bringing each successive cartridge into position, and locked into alignment with the barrel for firing.
  • A rotating cartridge holder in a revolver. The cartridges are held in the chambers and the cylinder turns, either to the left or to the right depending on the gun maker's design, as the hammer is cocked.
  • A shotgun barrel with no choke constriction at the muzzle.
Cylinder Drum

[sil-in-der]   [druhm]

  • On a revolver, a spring activated device housed in the bottom of the frame beneath the cylinder that engages alignment notches in the cylinder. It stops the cylinder's rotation and holds it in place each time a chamber in the cylinder is in alignment with the barrel.

(dăm′ə-sēn′, dăm′ə-sēn′)

  • A form of decoration sometimes performed on firearms whereby very thin precious metal (normally gold) is hammered in artful designs directly onto the steel surface of the gun. Cheaper to accomplish, normally gaudier, and certainly less durable than gold inlay.
Damascus Barrels


  • Barrel tubes built up by twisting alternate strips of iron and steel around a fixed rod (mandrel) and forge-welding them together in varying combinations according to the intended quality and the skill of the maker. The rod was withdrawn, the interior reamed and the exterior filed until the finished tube was achieved. Damascus barrels may be recognized by any of a variety of twist or spiral patterns visible in the surface of the steel. Before the 20th century, barrels were typically built in this manner because gunmakers did not have the technology to drill a deep hole the full length of a bar of steel without coming out the side.
  • A gunmaker founded 1881 in St. Etienne, France, famous for its sliding-breech action. (Pronounced: darn, not darnay)
Date Codes
  • Amongst proof marks are codes enabling one to determine the date of manufacture of many guns
De Cocker
  • A type of action, usually of a break-open firearm, which readily allows release of mainspring tension, rendering the gun safe. In German: Handspanner.
Deeley Forend Release
  • A latch for securing the forend to the barrels of a break-open gun, operated by a short pull-down lever mounted to the center of the forend. Typically seen on Parker and Prussian Charles Daly guns. More properly known as a Deeley & Edge Fastener.
Delayed Blowback

(dĭ-lā′)   (blō′băk′)

A variant of the blowback principle in which the blowback operation is by some means retarded (e.g., by a fluted or grooved chamber). For more powerful rounds or for a lighter operating mechanism, some system of delayed or retarded blowback is often used, requiring the bolt to overcome some initial resistance while not fully locked. Because of high pressures, rifle-caliber delayed blowback firearms, such as the FAMAS and G3, typically have fluted chambers to ease extraction.

Gun Gas Delay Blow Back
Gun Gas Delay Blow Back



























Demi bloc Barrels
  • (called Chopper-lump barrels in British) - A method of joining the two separate tubes of a set of barrels where the right-hand half of the pair of lumps under the barrels are forged integrally with the right barrel and the left-hand half of the pair of lumps under the barrels are forged integrally with the left barrel. Chopper-lump barrels can be recognized by the fine joint-line running longitudinally down the center of each lump. This method of jointing barrels is the best because: 1. It is the strongest in relation to its weight, and 2. Because it allows the two barrels to be mounted closest to each other at the breech end, reducing problems regulating the points of aim of the two separate barrels.
  • Damage to a shotgun barrel from having taken a hit from a hard object. Thinner-walled barrels are more subject to the risk than thicker ones. While dents a few thousandths of an inch deep may not be dangerous, deeper ones ought to be raised by a skilled gunsmith before firing the gun, best done using a hydraulic dent-raising tool.


  • A small single-shot or multi-barreled (rarely more than two) pocket pistol. The design was first produced by Henry Deringer, under the brand name Deringer. When used to refer to any other brand of the same design, derringer is spelled with two r's and is not capitalized.


  • to cause (a bomb, mine, etc) to explode or (of a bomb, mine, etc) toexplode; set off or be set off
Diamond Grip
  • The cross-sectional shape at the wrist of a long gun, describing a soft diamond shape (as opposed to a circle or an oval) in the interest of comfort---and a better frame of reference for the gun's position.
  • A piece of tooling used to form a sequence of uniform parts through the use of heat and/or pressure; especially, in firearms terminology used to form brass cartridge cases accurately to their correct size for reloading.
Disc Set Strikers
  • Circular steel fittings, about 1/2 inch in diameter, screwed into the breech face of a gun and through which the firing pins pass. Firing pin bushings allow the convenient replacement of broken firing pins. They also allow the renewal of an older gun where, over the decades, leakage of high-pressure gas from corrosive primers has eroded the breech face around the firing pins; and replacing these bushings with new ones, slightly oversized can compensate for a situation where proper headspace has been compromised. In American: Bushed Firing Pins.


Most commonly, a device in auto pistols that prevent the pistol from being fired until the breech is completely shut and prevents the pistol from being fired fully automatic.



















Dog Lock
  • An early form of Flintlock, incorporating an external catch to lock the hammer
Dolls Head
  • A rib extension on a break-open gun, ending in a circular or semi-circular shape in plan (resembling the head of a doll), mating into a similarly-shaped recess in the top of the receiver, designed to resist the tendency of the barrels to pull away from the standing breech when firing. Because an action's centerpoint of flexing when firing is at the base of the standing breech, not at the hingepin, a passive doll's head extension makes an effective extra fastener, even without additional mechanical locks operated by the opening lever.

Dope of a Scope

dōp                     skōp

"A sniper will enter information into a data, or DOPE (Data On Personal Equipment) book, such as lot number, temperature, wind speed/direction, humidity and altitude. If the same conditions are encountered again, the data is available to assist in making an accurate shot."

After you zero the scope... doping is simply calculating the number of clicks from your zero, to account for bullet drop and drift at various ranges, for a specific ammunition load.

A DOPE has to be calculated for each ammo load that has different bullet weights and velocity.

Dope of a Scope Dope of a Scope

Doppelbüchs Drilling
  • German term for a three-barrel firearm comprising two side-by-side rifle barrels over one shotgun barrel.
Double Action

[¦dəb·əl ′ak·shən]

A type of lockwork in either a revolver or auto pistol that permits the hammer to be cocked either by direct manual action or by a long pull on the trigger. The term is extensively used (somewhat erroneously) as a synonym for "trigger cocking." Thus, such phrases as "The double-action pull was very smooth" or "The Seecamp is a double-action-only auto pistol."

Single & Double Action Revolvers Single & Double Action Revolver                                                              Double Action vs Single Action Double Action vs Single Action

Double Action DA
  • A type of firearm that may be discharged either by manually cocking the weapon and then pulling the trigger or by using trigger action to both cock and fire the weapon. Originally used only for revolvers but now common in semi-autos as well, Now it commonly means a revolver or pistol on which a long trigger pull can both cock and release the hammer to fire the weapon. In a revolver this action also rotates the cylinder to the next chambered round.
Double Action Single Action DA SA
  • A type of firearm that is designed to operate in double action on the first shot, and in single action on the second and subsequent shots.
Double Action Only DAO
  • Is a type of firearm in which the firing mechanism cannot be cocked in a single-action stage. Firing always occurs as a double-action sequence where pulling the trigger both cocks and then fires the gun.
Double Barrel
  •  A shotgun with two barrels either side by side or one over the other.
Double Feed
  • A malfunction in which the spent case fails to eject from a semi-automatic firearm and blocks the chamber. As the fresh round is brought forward it cannot enter the chamber. It is cleared by stripping the magazine from the gun, racking the slide several times to eject the spent case, and then reloading.
Double Rifle
  • Two independent rifles, built on one frame, designed to allow two virtually instantaneously quick, totally reliable shots. The barrels may be arranged either side-by-side or over-and-under. The apogee of the gunmaker's art. Particularly useful against dangerous game, which may be moving, and in your direction, with vengeance on its mind.
Double Rifle
  • Two independent rifles, built on one frame, designed to allow two virtually instantaneously quick, totally reliable shots. The barrels may be arranged either side-by-side or over-and-under. The apogee of the gunmaker's art. Particularly useful against dangerous game, which may be moving, and in your direction, with vengeance on its mind.
Double Tap
  • Two shots fired in rapid succession. Generally without getting a new sight picture on the target. If the second shot is fired after a second sight picture is captured it may instead be called a controlled pair.
  • The unwanted tendency for a double barreled gun to fire both barrels virtually simultaneously---the recoil from the first barrel's discharge jarring the sear for the second barrel of its notch, causing it, too, to fire. The result of worn parts, coagulated old oil or unskilled maintenance..
Dovetailed Barrels
  • The usual way of building a set of side-by-side barrels. Two raw tubes are filed to approximate their final contour. A solid block of steel is then filed to shape, fitted between the two tubes at the breech end with about 3/4" exposed on the underside and soldered or brazed into place to form the lump(s).
Down Range
  • The area of a gun range where firearms are pointed when they are fired. The area of the range forward of the firing line.


  • A unit of measure traditionally used for black powder shotgun charges. Today, used for smokeless powders on the basis of the new propellant's equivalent performance to that weight of black powder. Thus, a shotgun shell marked 3 - 1 1/8 would be loaded with the smokeless powder equivalent of 3 drams of black powder, and with 1 1/8ounce of shot. 1 Dram = 1/16 ounce = 437.5 grains.
  • A three-barrel shoulder-fired gun, typically with two identical side-by-side shotgun barrels mounted above one rifle barrel. Built primarily in Germany and Austria. If with two rifled barrels above a single rifled barrel, it is called a Bock Drilling
Driving Bands

(drī′vĭng)  (bănds)

Portions of a bullet's bearing surface that actually contact the bore. Driving bands are separated by crimping and lubrication grooves.  In a small-arms rifle, the entire bullet is typically covered in copper or a similarly soft alloy, so the entire bullet is its own driving band.

Bullet Driving Bands
Bullet Driving Bands














  • The distance from an imaginary straight line of sight extended along the rib of a shotgun rearward towards the butt---to the top of the stock at the comb or the heel. (In British: Bend). The amount of drop determines how high or how low a gun will naturally point. Browning, in its infinite wisdom, considers that 2 3/8" drop at the heel will best fit the broadest range of shooters for field use. This measurement can therefore be considered "normal." A gun with less drop will shoot higher, while a gun with more drop will shoot lower for a given individual. When the gun is comfortably mounted with the cheek snugly on the comb, the drop is about right when you can see the front bead and just a little rib over the standing breech. Trap guns usually have less drop because they are supposed to shoot a little high in order to hit an almost universally rising target. Standard wisdom indicates that the drop is about right for a mounted trap gun when the front bead seems to rest just on top of the middle bead like two parts of a snowman, or forming a figure-eight.
Drop Box Magazine
  • An extra-deep magazine typical of large caliber rifles for dangerous game. The line of the underside of the wrist does not carry straight forward as with ordinary rifles. Rather the rear of the magazine aligns more towards the center of the forward edge of the trigger-guard, typically allowing at least one extra cartridge to be carried.
Drop Points
  • Small, raised-carved details on either side of a double gun, behind the lockplates of a sidelock or behind the flat sidepanels of a boxlock, in the shape of a hanging drop of water. Also called teardrops.
Drop Safety
  • A mechanical safety that prevents the gun from firing when it is unintentionally dropped. Some state governments require drop-testing of all handgun designs sold within the state.
  • A variation on the Anson & Deeley boxlock design, introduced by Westley Richards at the end of the 19th Century, whereby the locks themselves are removable, without tools, from the action body for cleaning or repair through a hinged or a detachable floorplate. A droplock action may be distinguished from an ordinary Anson & Deeley action at sight because it has no action pins visible on the side of the receiver.
Dry Fire
  • To pull the trigger and release the hammer of a firearm without having a cartridge in the chamber. While benign enough with a Mauser action, it can shatter the differentially-hardened internal parts of a break-open gun which, upon firing, are designed to have the shock of the hammer's blow absorbed somewhat by the soft brass of the primer. If you must experiment with the trigger(s) and the action of a fine double gun, be sure to use snap caps---which safely replicate the buffering effect of an actual cartridge.
DST or Double Set Trigger
  • On a rifle, optionally pulling the rear (set) trigger converts the front (main) trigger to a light, hair trigger---too light and sensitive to be carried safely in the field. While the front trigger is always at the ready, if one has the time, using the set trigger feature may allow for a more accurate long-distance shot. Operates using its own miniature firing mechanism (sear, spring and hammer) when cocked, to multiply the force of a pull on the main trigger.

DT or Double Triggers
  • One for each barrel. Double triggers are better than single triggers on a double gun because:  1. They are simpler in design, therefore making the gun lighter and more reliable.  2. They are less prone to double-firing.  3. In the hands of an experienced shooter they are faster.  4. They allow immediate selection of which barrel to fire - the immediate selection of the pattern to throw - even while the grouse is flushing
  • A round of ammunition that does not fire.
Duelling Pistol

(do͞o′əl, dyo͞o′-)

  • Single shot pistols, of a design originating in England, in vogue circa 1770 - 1850, built necessarily in pairs, either of flintlock or percussion ignition, usually finely made and cased together with loading accessories. Dueling pistols tended to be lighter and sleeker than their contemporary service pistols. They tended to have smoothbore (or sometimes secret, scratch-rifling), octagon (or octagon-to-round) barrels around nine or ten inches long of some form of damascus steel, bores just over a half-inch, ramrods, rudimentary sights front and rear, single-set triggers, roller-bearing frizzens and curved grips integral with full or half-stocks. They were usually of high quality construction, sometimes with silver furniture, but normally of relatively plain decoration.
Dummy Round
  • An inert ammunition-shaped object, used in practice to simulate misfeeds and other malfunctions and also used in dry fire practice.
Dust Cover
  • A small hinged or sliding door covering the ejection port of a firearm to prevent detritus from clogging the works.
Ear Muffs
  • Hearing protection that completely covers both ears and is usually attached to a headband
Ear Plugs
  • Hearing protection that fits inside the ear canal.
  • Slang for hearing protection, muffs or plugs. The use of specially designed ear muffs or plugs that reduce the intensity of the sound reaching the ears is of course recommended. Some of the guns are so loud that a single shot can can cause permanent damage to unprotected ears.
Ejection Port
  • The opening through which the empty, spent ammunition case is ejected from of a firearm.
Ejection Rod
  • The sliding metal dowel located at the muzzle end of a revolver cylinder. After firing, the shooter opens the cylinder and depresses the front end of the ejection rod, which forces the empty cases out of the cylinder.

noun - ejec·tor (ĭ-jĕk′tər)

  • A device for expelling a fired cartridge case from a firearm, one that ejects; especially : a mechanism of a firearm that ejects an empty cartridge
  • Fittings inset into the breech end of a pair of barrels of a break-open gun that kick out fired shells, while only raising un-fired shells enough to be removed by hand. Recognizable at a glance on the breech end of a double gun because the fitting is split in two---one ejector for each barrel.
  •  A spring-activated mechanism for the ejection of ammunition or and empty shell casing. On doubles, each barrel has a separate ejector.

Auto Ejector Auto Ejector                                                   Revolver Ejector Rod Revolver Ejector Rod

Ejector Star
  • On a revolver, the collective ejector, manually operated through the center of an opened cylinder, when activated, clears all chambers at once.
Ejector Timing
  • The adjustment of the ejector mechanism by gun maker or gunsmith so that both ejectors of a double gun will fire at the correct instant when gape is sufficient as the barrels are dropped, simultaneously, and with identical force.
Electronic Hearing Protection
  • Ear muff hearing protection that has internal electronics that amplify human voices while excluding all noises louder than a given decibel rating.
  • The setting on the sights of a firearm that controls the vertical placement and the altitude above mean sea level. This is important for long range precision shooting because the air density changes with elevation and affects the path of the bullet.
  • Adjustment of the point of impact of a firearm in the vertical plane; the knob used on an iron sight or telescopic sight to raise or lower the point of impact.
  • Capability to perform work. As measured in foot-pounds, the amount of force it takes to lift and object weighing one pound, one foot. To calculate the energy, in foot-pounds, of a bullet in flight at any point on its trajectory:

                W = Weight of the bullet in grains.    V =  Velocity in feet per second

Engine Tuned
  • An jeweled treatment on a steel part done both for a finished look and to hold oil on the surface. An abrasive-impregnated rubber bit is used to describe a circular pattern on the surface of the steel, then moved just a little less than distance of the diameter of the bit, touched to the surface again, and the process repeated until the steel surface is covered with small regular rows of circular swirls
English Casing
  • A style of gun case whereby all the cased components are secured into more open box-like compartments---the barrels and action secured well enough, but the accessories liable to moving about a bit. An alternative to French casing, where all the cased components---barrels, action and accessories are fitted into shaped compartments with no space around them
English Grip
  • A straight-wrist grip, typical on English shotguns, built for graceful aesthetics, light weight and fast handling. May be ovoid or somewhat diamond-shaped in cross-section.


noun ero·sion \i-ˈrō-zhən\

  • Deterioration of the inner surface of a firearm's barrel due to the intense heat of a cartridge's discharge. High-velocity rifles are particularly susceptible to this wear, especially near the throat.

noun es·cutch·eon \is-ˈkə-chən\

  • A plate, typically of more complex outline than a simple oval, typically of brass or precious metal, inlaid into a gunstock or a gun case, upon which is engraved the initials, monogram or coat-of-arms of the owner.


  1. understood by or meant for only the select few who have special knowledge or interest.
  2. belonging to the select few.
  3. private; secret; confidential.
  4. (of a philosophical doctrine or the like) intended to be revealed only to the initiates of a group.
  • Westley Richards' trademark name for a Paradox-rifled gun, in 12-bore.
  • Any substance (TNT, etc.) that, through chemical reaction, detonates or violently changes to gas with accompanying heat and pressure.
  • Marketing term coined by Purdey around 1855 to denote a high velocity rifle---as powerful as an express train.
Express Sights
  • A "V" shaped rear leaf sights mounted to a rifle barrel on a block or on a quarter-rib, sometimes solid standing, sometimes folding, and often mounted in a row of similar leaves, each of a slightly different height, marked with the range for which each is regulated.
Extended Top Tang
  • A display of gun making skill with a possible benefit of strengthening the wrist of a heavily-recoiling rifle, whereby the top tang of the action is made extra long, shaped and inletted into the top of the buttstock, extending along the top of the wrist and up over the comb. Popularized by Holland & Holland and adopted by several of the finest contemporary rifle makers in the USA.
External Safety
  • A safety lever found on the outer surfaces of the firearm and accessible to the user.
  • A device that withdraws or elevates a fired shell casing from the chamber as the breech mechanism (slide) is opened.
Eye Dominance
  • Although we have two eyes for depth perception and for spare parts, there is a natural tendency for one eye (the master eye) to take precedence over the other, regardless of the relative visual acuity of each eye. It is a fortunate condition when the eye on the side of the shoulder where one is comfortable mounting a gun is also the dominant eye.

    To test for eye dominance, pick out a small object several feet away. With both eyes open, center your right index finger vertically over the object. Close your right eye. If your finger appears to jump to the right, you are right eye dominant. Then open your right eye and close your left eye. If your finger remains in position in front of the object, you have confirmed your right eye dominance. Alternatively, if in the above test, upon closing your right eye your finger remains in position covering the object, you are left eye dominant. If you close your left eye instead and your finger appears to jump to the left you have confirmed your left eye dominance.

    Eye dominance problems can be treated with 1. A severely-cast, crossover stock to bring the dominant eye in line with the gun's line of sight, 2. A patch over the dominant eye, or just a small piece of frosty Scotch tape on shooting glasses intercepting the dominant eye's line of sight, 3. Fully or partially closing the dominant eye, or 4. Learning to shoot from the dominant-eye shoulder.  While less convenient, methods that retain the use of both eyes better preserve the ability to perceive depth in three-dimensional space---a great benefit in wingshooting.

Eye Relief
  • The distance that equates the exit pupil size of a rifle scope's ocular lens to the entrance pupil of the user, in order to achieve the largest, unvignetted view. This distance must be sufficient to ensure that the ocular rim of the scope does not lacerate the shooter's eyebrow upon recoil. And, the scope should be positioned so that eye relief is suitable when the rifle is comfortably mounted.
  • Slang for safety glasses or other protection for the eyes. All shooters and spotters are required to wear eye protection while shooting is in progress.
Facile Princeps
  • "Easily the Best". A proprietary boxlock action design by W W Greener, similar to the Anson & Deeley, but more easily cocked with the fall of the barrels; the forend iron pressing on a rod passing through the front barrel lump and acting upon cocking bars just below and behind the front Purdey underbolt.
Failure To Extract
  • A semi-automatic firearm malfunction in which the extractor fails to move the empty case out of the way as the slide travels back. A failure to extract often causes double-feed malfunction.
Failure To Feed
  • A semi-automatic firearm malfunction in which the slide passes entirely over the fresh round, failing to pick it up to insert into the chamber as the slide returns to battery.
Failure To Fire
  • Any malfunction that results in no shot fired when the trigger is pulled. Commonly caused by a failure to feed, bad ammunition or a broken firing pin.
Falling Block
  • A type of action used primarily for single shot rifles whereby some kind of lever actuates a breechblock, moving it downwards in a vertical recess to expose the chamber. May have visible or enclosed hammer. For any given barrel length, it allows a shorter overall rifle length compared to a bolt action because no space is taken up by the forward-and-back cycling of the bolt. Most of the better British makers produced them in limited numbers around the turn of the last century, the Farquharson being the most iconic. Perhaps the best-known falling block action today is the Ruger No.1.
False Muzzle
  • An attachment made for the muzzle of an individual rifle barrel in the interest of extreme accuracy. The bullet is loaded through the false muzzle, which begins to swage grooves into the projectile exactly in line with the rifle's bore, and is then ramrodded fully to the breech. Then, the rifle (which can be either breech or muzzle loading) is set up to fire a mechanical bullet, precisely pre-rifled to fit that particular bore. Often used in conjunction with a bullet starter.
Fancy Back
  • Any of a number of different contour variations to the rear of a boxlock action abutting the head of the stock to improve the look and justify a higher price than for a plain gun. Also: Scalloped Receiver.
Farquharson Action
  • One of the classic British falling block single shot rifle actions, patented by John Farquharson in 1872, adopted by George Gibbs and others.


  • Westley Richard's trademark name for a Paradox-rifled-barreled gun, in 20 and 28-bor
Feed Ramp

  • An inclined, polished area on a repeating firearm, just behind the chamber, that helps guide a cartridge into the chamber when pushed forward by the closing bolt.

  • Hemispherical outgrowths of the receiver of a double gun that mate with the breech ends of the barrels. The term derives from the flanges (or fences) in this position on a muzzle loading gun that were designed to protect the eyes of the shooter from sparks and escaping gasses.
FFL Federal Firearms License


  • Federal Firearms [Dealer's] License. Under federal law, to ship a firearm, a selling dealer must have in his possession a copy of the receiving dealer's license.
  • A Federal Firearms License (FFL) is a license in the United States that enables an individual or a company to engage in a business pertaining to the manufacture or importation of firearms and ammunition, or the interstate and intrastate sale of firearms.
Field Forend


  • A relatively slender forend on an over & under gun (as opposed to a beavertail forend). Over & Under counterpart of a Splinter Forend
Field Grade


  • A generic term for a plain, functional, unembellished firearm used to hunt in rough terrain where one might prefer not to put a more expensive, deluxe grade gun at risk of damage.
Field Gun


  • A shotgun, generally stocked to shoot where it is pointed and of relatively light weight because one often carries it a great distance for upland birds---the consequent recoil not being an important factor because one actually shoots it very little.


  • The forward-most part of a sidelock gun's stock; the slender flutes of wood extending along the lockplates, heading up to the receiver body. Also: Horns
Fire Blue


  • A Brilliant, slightly iridescent, and perishable blue finish on highly-polished steel achieved by heating to a temperature of about 500°F. Often seen as small-part details on pre-World War I Colts and the best contemporary American custom rifles.
Fire Form

  • The act of firing a relatively smaller cartridge in a rifle with a relatively somewhat larger chamber in order to expand the cartridge case to the larger size. This action should not be undertaken except in very particular instances or catastrophic damage may occur. It should only be done when the larger chamber is of a closely related design to that of the smaller cartridge case---such as firing a .375 H&H Magnum cartridge in a .375 Weatherby chamber, or firing a .22 Hornet cartridge in a .22  K-Hornet chamber to re-form the brass to the latter "improved" cartridges.

noun fire·arm \ˈfī(-ə)r-ˌärm\

  • small arms weapon, as a rifle or pistol, from which a projectile is fired by gunpowder.
  • A device which, on demand by activating some sort of switch like a trigger, ignites a very-rapidly burning propellant or an explosive, expels a projectile such as a bullet, or projectiles such as shot, from a tubular barrel (or barrels) with sufficient force as to cause acute bodily harm to the target, animal, or person which it hits.
  • A rifle, shotgun or handgun using gunpowder as a propellant. By federal definition, under the 1968 Gun Control Act. Air guns are not, by definition, firearms.
  • A volume of fire delivered by a military unit. Incorrectly used by the media to mean the ability of a small arm to be discharged many times without reloading.
Firing Line
  • A line, either imaginary or marked, from which people shoot their firearms down range.
  • The positions at which troops are stationed to fire upon the enemy or targets.
Firing Pin


  • The narrowly rounded, pointed component of a cartridge firearm that impacts and causes detonation of the primer. This may be mounted coaxially with a coil mainspring in a bolt rifle, may be a small replaceable tit mounted into the breech face of a sidelock break-open gun or an integral part of the [enclosed] hammer of a boxlock gun.
Firing Pin Block
  • A type of internal safety that prevents the firing pin from moving forward for any reason unless the trigger is pulled.
Five Screw Four Screw Three Screw
  • Terms relating to Smith & Wesson double-action revolvers. The five screws were four retaining the sideplate and one at the front of the triggerguard. From the introduction of the Hand Ejector in 1905, there were five screws. Then, around 1955 S&W deleted the top sideplate screw. Around 1961, they deleted the triggerguard screw. Collectors find cheapening of fine products irritating. Consequently, all other things being equal, with Smith & Wesson revolvers, the more screws, the better.
Fixed Ammunition
  • A complete cartridge of several obsolete types and of today's rim fire and center-fire versions.


  • The tendency for blue finish to deteriorate into rust, seemingly without either wear or ill treatment. Winchester Model 1892 receivers are particularly vulnerable to this defect. But, at least the condition indicates that, almost certainly, the remaining finish at least is original.


  • A cartridge with a pronounced rim at the base. While not as easy-feeding in a repeating firearm as a rimless cartridge, far more reliably extracting in a break-open firearm particularly important in a heavy double rifle for use against big game that might fight back.
Flash Gap

(flăsh)  (găp)

The distance between the face of a revolver's cylinder and the breech end of the barrel. U.S. industry standards call for a gap of .006-inch, with a .003-inch tolerance in either direction. (The SAAMI advises that 0.012" is an industry maximum for revolver flash gap)

Flash Gap Tolerance
Flash Gap Tolerance














Flash Hider Flash Suppressor
  • A muzzle attachment intended to reduce visible muzzle flash caused by the burning propellant. Flash reducers lessen glare as seen by the shooter, but do not hide the flash from other observers to the front or side of the firearm.
Flash Pan
  • A tiny bowl-shaped vessel, attached to the side of a flint lock, to hold the priming charge of gunpowder, which in turn is protected from wind, rain and the adverse effects of gravity by the combination hinged frizzen-flashpan cover.
Flat Point Flat Nose
  • A bullet shape with a flat nose rather than a rounded one.
Flat Point Checkering
  • A traditional English style of checkering gunstocks whereby the diamonds are not brought to sharp points. While not offering as firm a grip as standard sharp point-pattern checkering, it is both more durable and allows the grain structure of the wood to show through better.
Fleur de Lys

[flur-dl-ee, -ees, floo r-; French flœr-duh-lees]

  • A design element used on the French royal coat of arms, a stylized lily flower, frequently appearing in the checkering designs of American custom rifles.
  • To jerk a firearm off target inadvertently at the instant of firing in timid anticipation of recoil.
  • Jerking the gun downwards just before the shot fires. Commonly caused by learning to shoot with a gun more powerful then they are ready for.
  • A hard, sedimentary, sub-micro-crystalline form of quartz, which when knapped (dressed to shape by chipping) and then struck against steel can be used to create sparks.
  • hard stone, a form of silica resembling chalcedony but more opaque,less pure, and less lustrous. a piece of this, especially as used for striking fire.


  • A system of firearms ignition, in general use circa 1660 - 1825, whereby the pull of a trigger releases a sear from a notch in a spring-loaded hammer, which holding a properly knapped piece of flint, strikes a vertical slab of steel (called a frizzen) scraping off tiny molten particles of the steel, and pushing it forward causes an integral flashpan cover to open forward, exposing a bit of fine gunpowder below, which when contacted by the falling sparks, ignites and sends a flash of fire through the touchhole, into the loaded breech setting off the main charge and firing the gun. The Flintlock system was supplanted by the Percussion system around 1820.
Floated Barrel
  • A rifle barrel mounted firmly to the receiver (which, in turn, is mounted firmly to the stock) but not touching the forend. Done so that the stock will not adversely effect accuracy by impinging upon the natural free vibration of the barrel when the rifle is fired.
Floating Firing Pin

[′flōd·iŋ] [′fīr·iŋ ‚pin]

On a revolver, a firing pin that is mounted inside the frame, as opposed to being pinned to the hammer. (A device used in the firing mechanism of a gun, mine, bomb, fuse, projectile, or the like, which strikes and detonates a sensitive explosive to initiate an explosive train or a propelling charge.)

Revolver with Floating Firing Pin
Revolver with Floating Firing Pin


















  • A cover, usually of metal, usually hinged and latched, on the bottom of a bolt action rifle action which, when opened, allows the internal magazine to be emptied.
Fluid Steel Barrels
  • Barrels made of homogeneous steel (not damascus steel) --- standard practice for over a century
Fluted Barrel
  • A rifle or pistol barrel, into which longitudinal grooves have been milled. Fluted barrels, while more expensive to make than round barrels, dissipate heat more rapidly and they provide a better stiffness-to-weight ratio.
Fluted Comb
  • A carved detail at the point of the comb, a concave groove for more graceful aesthetics, and to allow a more clearance for a more comfortable position for the thumb as it wraps over the wrist than does a fatter, non-fluted comb.


  • Stands for Full Metal Jacketed. A bullet completely enclosed (except for the base) in a hard metal jacket (usually an alloy of copper, sometimes a mild steel). This is the only type of bullet permitted in warfare.
  • A type of round in which in which the lead core bullet is encased in a harder metal jacket on the front and sides.
FMJ Bullets
FMJ Bullets


















Folding Stock
  • A long gun stock that may be doubled over for conveniently compact storage.
Follow Through
  • Holding the trigger to the rear after the shot has fired, until the sights are back on target, at which time the trigger is released.
  • A smooth, sometimes contoured plate, within a magazine, at the top of a spring, across which cartridges slide when being loaded into a chamber.
Forcing Cone

[′fȯrs·iŋ ‚kōn]

  • The portion at the breech of a revolver's barrel that tapers into the rifling. Tapered beginning of the lands at the origin of the rifling of a gun tube; the forcing cone allows the rotating band of the projectile to be gradually engaged by the rifling, thereby centering the projectile in the bore.
Revolver Forcng Cone
Revolver Forcing Cone


















  • One of the three major dismountable components of a break-open gun (the others being the barrel(s) and the action/buttstock) which secures the barrels to the receiver, often houses the ejector mechanism, and for some, provides a handle for the one's secondary hand.

  • That part of the stock forward of the action and located below the barrel or barrels. It is designed to give the shooter a place to hold the front end of the gun and protects the shooter's hand from getting burned on the hot barrel.
Forend Iron
  • The steel skeleton of the forend, into which any moving parts are fitted and which mates to and revolves about the action knuckle when the gun is opened.
  •  The gritty residue that cleaned out of the barrel and all areas of the firearm in order to clean it.
Fouling Shot
  •  A shot fired in a clean rifle barrel to put the barrel into the normal slightly dirty state from which it is fired. Often, a rifle will shoot to a different point of aim with this shot as compared to the subsequent shots.
Four Rules Of Firearm Safety
  • The four universal rules of firearms safety, which apply every single time a firearm is handled in any way or for any reason.

  • Rule One: All guns are always loaded.
  • Rule Two: Never point your firearm at anything you are not willing to destroy.
  • Rule Three: Never put your finger on the trigger unless your sights are on target.
  • Rule Four: Be sure of your target and what is behind it.

Stands for "feet per second," by which bullet velocity is measured. The foot per second (plural feet per second) is a unit of both speed (scalar) and velocity (vector quantity, which includes direction). It expresses the distance in feet (ft) traveled or displaced, divided by the time in seconds (s, or sec). The corresponding unit in the International System of Units (SI) is the metre per second.

Feet Per Second Ballistic Chart Feet Per Second Ballistic Chart

  • The common part of a handgun to which the action, barrel and grip are connected.
French Casing
  • A style of gun case, where all the cased components---barrels, action and accessories are fitted into shaped compartments with no space around them. An alternative to English Casing whereby all the cased components are secured into more open box-like compartments---the barrels and action secured well enough, but the accessories liable to moving around a bit.
French Gray
  • An acid etched or phosphate finish, applied typically to shotgun actions, forming a gray-colored, non-reflective matte finish which also provides some protection from rust. Also called, gray-etched.
  • That part of a flintlock action that receives the blow of the flint-tipped hammer, which then yields tiny molten fragments of steel---sparks---which fall into the flashpan, igniting the priming charge and thence, through the touchhole, the main charge
Front Sight
  • The front sight is placed at the muzzle end of the barrel. It is often (but not always) in the form of a dot or a blade. To attain a proper sight picture and shoot with the greatest degree of accuracy, the shooter's eye should be focused sharply upon the front sight while shooting, allowing both the rear sight and the target to blur somewhat.
  • Front, metal, part of a handgun's grip, which together with the backstrap, provides a mounting frame for the grip panels.
  • The part of a revolver or pistol grip frame that faces forward and often joins with the trigger guard.
Full Stock
  • A rifle or carbine with a one-piece stock extending to the muzzle. Sometimes called a Mannlicher stock, although such a term is confusing because Mannlicher Schoenauer rifles are built with both full and half stocks. Traditional in Europe for close-range woodland hunting, but not noted for extreme, long-range accuracy.
Funeral Grade
  • A colloquial term to describe a break-open gun, of any quality but often of the very highest, bearing the least possible decoration; having an all-blued receiver with either no engraving at all or only a simple borderline.
  • In British-speak, the visible small steel parts of a double gun: top lever, trigger guard, safety tab, forend release lever, etc. These parts are normally blued.
Gain Twist
  • A form of rifling where the helical angle sharpens progressively down the bore in the interest of maximizing the bullets ultimate rotational speed by initiating it slowly.
  • Glock Auto Pistol, a type of ammunition

[gahr-ni-cher, -choo r]

  • A deluxe set of several different associated weapons, being any combination of rifle, shotgun, various handguns, and possibly a knife or two, cased together with appropriate cleaning and loading tools.
  • Something that garnishes; decoration; adornment.
  • The superheated air and other stuff produced by burning powder. Gas pressure is what sends the bullet downrange.
Gas Check

Copper-alloy cups affixed to the bases of specially designed cast bullets with the intention of reducing deformation of the base under high heat and pressure and thus reducing leading. A gas check is a device used in some types of firearms ammunition. Gas checks are used when non-jacketed bullets are used in high pressure cartridges, to prevent the buildup of lead in the barrel and aid in accuracy.

Gas Check Bullet
Cast bullets as cast (left), with gas check (center) and lubricated (right)


















Gas Operated

(găs)  (ŏp′ə-rāt′)

A system of operating an automatic or semi-automatic firearm in which a portion of the powder gasses is bled off from the barrel and used to activate a piston or similar device that cycles the breechblock or slide. Gas-operation is a system of operation used to provide energy to operate autoloading firearms. In gas-operation, a portion of high pressure gas from the cartridge being fired is used to power a mechanism to extract the spent case and chamber a new cartridge. Energy from the gas is harnessed through either a port in the barrel or trap at the muzzle. This high-pressure gas impinges on a surface such as a piston head to provide motion for unlocking of the action, extraction of the spent case, ejection, cocking of the hammer or striker, chambering of a fresh cartridge, and locking of the action.

Gas-operated firearm Gas-operated firearm (long-stroke piston, e.g. AK-47). 1) gas port, 2) piston head, 3) rod, 4) bolt, 5) bolt carrier, 6) spring

Gas Retarded

A type of delayed blowback operation in which a portion of the powder gasses is bled off from the barrel to retard the rearward travel of the slide--used in the Heckler & Koch P7 series of 9mm pistols. The P7 is a semi-automatic blowback-operated firearm. It features a unique gas-delayed blowback locking system modeled on the Swiss Pistole 47 W+F (Waffenfabrik Bern) prototype pistol (and ultimately on the Barnitzke system first used in the Volkssturmgewehr), which used gas pressures from the ignited cartridge and fed them through a small port in the barrel (in front of the chamber) to retard the rearward motion of the slide. This is accomplished by means of a piston contained inside of a cylinder located under the barrel that opposes the rearward motion of the slide until the gas pressure has declined—after the bullet has left the barrel—hence allowing the slide to end its rearward motion, opening the breech and ejecting the empty cartridge case.

Gun Gas Retard Blow Back
A schematic of the P7's gas-delayed blowback system.



























Gas Vent
  • A passage built into a firearm to allow the safe conduct of unexpected gas, as from a pierced primer, to minimize damage both to the gun and to the shooter.
Ghost Ring Sight
  • A type of aperture rear sight with a large opening and a thin rim that seems to fade out when the shooter looks through it. Sometimes installed on rifles and shotguns intended for home defense or police use.
  • Swabbing wet epoxy over the inletted portion of a stock, covering the metalwork with a release agent and pressing the barreled action into the wood. A process undertaken to compensate for imperfect wood-to-metal fit
Gloaming Sight


  • A second, folding or pop-up front sight bead of larger than usual size, perhaps not as accurate as a normal fine bead, but easier to see in the gloaming (twilight) or dawn.
Globe Sight
  • A front sight assembly, primarily for target rifles, consisting of a tube, housing interchangeable beads and blades. The tube guards against imperfect aiming due to sight pictures influenced by reflections.
  •  A unit of weight measurement used for bullets and gunpowder. The more grains, the heavier the bullet. Powder is also measured by grains, but this is generally of interest only to re-loaders. There are 7000 grains to a pound.
  • The degree to which the barrel(s) of a break-open gun drop down; the size of the opening space which should be sufficient to allow for ease of loading, unloading and properly-functioning ejection. A good gape is easier to achieve on a side-by-side than an over & under where the bottom barrel is well-enclosed by the action body.
Green Ammunition
  • Ammunition that contains no lead in any component.
Greener Crossbolt
  • A tapered round bar, operated by the toplever of a shotgun, passing transversely behind the standing breech of a side-by-side gun and through a matching hole in a rib extension; to strengthen the lock-up. Scott's crossbolt operates similarly, but is square in cross-section.
Greener Safety
  • A safety catch mounted to the left side of a gun, just behind the receiver, which swivels fore and aft on a transverse rod. Often seen on drillings as well as on Greener's own shotguns.
Griffin And Howe Sidemount
  • A quick-detachable scope mount system built by the company of that name. The base fits to the side rail of a bolt action. The slide locks in place on the rail with two levers. (Pre-war mounts had a single lever.) Rings of various heights and diameters attach the scope of your choice to the slide. Mounting a scope high enough allows use of iron sights.
Grip Panels
  • The interchangeable surfaces that are installed on the part of the gun that you hold. Users change grip panels to improve the look or feel of the firearm, or to personalize it so that the gun is more suited to a different hand size. Some grip panels are chosen for function, while others are chosen for looks. Common grip-panel materials are wood, plastic, and rubber.
Grip Safety

[′grip ¦sāf·tē]

  • A device that prevents a handgun from being fired unless it is firmly gripped. Safety mechanism that prevents a gun from being fired unless the stock is firmly grasped while the trigger is pulled; used mainly on automatic pistols.
  • An interlock, often found on semi-automatic handguns, which helps prevent accidental discharge while adding no perceptible inconvenience when firing the arm intentionally. By the mere act of gripping the pistol in the hand, the shooter operates the grip safety, releasing its lock on the firing mechanism.
1911 Grip Safety
1911 Grip Safety


















Grip Straps
  • The exposed portion of a handgun's frame, the front strap and backstrap, that provides the foundation for the handgun's grip.
  • The handle used to hold a handgun. Often refers to the side-panels of the handle or the method by which the shooter holds the handgun.
  • Spiral cuts into the bore of a barrel that give the bullet its spin or rotation as it moves down the barrel. Technically is is the portion of the bore in a rifled barrel that has been machined away.
  • The cut-away, concave portions of the rifling inside the barrel of a firearm discharging a single projectile
  • A gathering of holes in the target. The group size is measured by finding the bullet holes that are the furthest apart from each other and measuring from the center of one hole to the center of the other hole.The closer the holes, the better. Obviously the number of shots fired affect the group size. Typical numbers are three, five and ten. From a statistics viewpoint a three shot group is virtually meaningless as a measurement of firearm accuracy. Five shot groups are acceptable. Some advocate a seven shot group as a good trade off between economy and statistical relevance.
  • A set of holes in a target left by a succession of bullets fired from the same rifle or handgun, using the same ammunition and sight setting. Fired (within the limits of one's marksmanship ability) to determine the inherent accuracy of the rifle/ammunition combination---and to aid in the proper adjustment of the sights. Measured by the distance, on center, of the two widest-disbursed holes.
  • The bore size of a shotgun determined by the number of round lead balls of bore diameter that equals a pound. It is used like "Caliber" for the shotgun.

  • System of measurement for the internal bore diameter of a smooth-bore firearm based on the diameter of each of that number of spherical lead balls whose total weight equals one pound. The internal diameter of a 12 gauge shotgun barrel is therefore equal to the diameter of a lead ball weighing 1/12 pound, which happens to be .729" (Or in British: Bore.) The Gauge/Bore system is also used, by convention, to describe the internal barrel diameter of large-bore, 19th century, English, single-shot and double-barrel rifles.
Guild Gun
  • Deriving from the concept of the "Masterpiece" required of applicants to submit to their guild for formal admission to the trade, a generous (but inaccurate) term used to describe a (usually Belgian or Germanic) gun with no maker's name at all. Before World War II, thousands of provincial gunsmiths would purchase unmarked finished guns and/or semi-finished components from larger gun factories and build individual shotguns for customers, some engraved with the retailer's name, some with no makers' name to be found anywhere on the gun.

noun \ˈgən\

A weapon that shoots bullets or shells. A weapon consisting of a metal tube from which a projectile is fired at high velocity into a relatively flat trajectory, especially: A portable firearm, such as a pistol, rifle, or revolver.

Smith & Wesson Semi-auto Pistol Smith & Wesson Semi-auto Pistol

Gun Control
  • Gun control (or firearms regulation) refers to laws or policies that regulate within a jurisdiction the manufacture, sale, transfer, possession, modification, or use of firearms by civilians.
  • Laws that control how guns are sold and used and who can own them.
  • Government regulation of the sale and ownership of firearms.
  • Regulation restricting or limiting the sale and possession of handguns and rifles in an effort to reduce violent crime.
  • Gun control laws aim to restrict or regulate the sale, purchase, or possession of firearms through licensing, registration, or identification requirements.


  • An explosive mixture, as of potassium nitrate, sulfur, and charcoal,used in shells and cartridges, in fireworks, for blasting, etc.
  • Chemical substances of various compositions, particle sizes, shapes and colors that, on ignition, serve as a propellant. Ignited smokeless powder emits minimal quantities of smoke from a gun's muzzle; the older black-powder emits relatively large quantities of whitish smoke.
Hagu Action
  • A modern, strong, simple, solid, well-engineered, falling-block, single-shot action designed by Munich-born Martin Hagn, now of British Columbia and made both by him and by Hartmann & Weiss of Hamburg.
Hair Trigger
  • A gun trigger so adjusted as to permit the firearm to be fired by a very slight pressure
  • A trigger that breaks from an extremely light touch.

Half Cock
  • A middle position for an external hammer that effectively provides a safety function. With a firearm with non-rebounding hammers, when on half-cock, the firing pin will not rest on the firing-pin. And, whether rebounding or non-rebounding, an inadvertent pull of the trigger should not release the hammer and fire the gun.
Half Grip
  • Round knob, semi pistol grip (Prince of Wales grip)
  • On guns so equipped, the hammer is the part that rotates to provide the percussive impact on the primer. The firing pin may be struck by the hammer, or the firing pin may be a part of the hammer. Not all guns have hammers. Many guns are equipped with strikers: notably Glock pistols and the vast majority of bolt action rifles. Hammers may be exposed or shrouded, spurred or bobbed.
  • The part of a gun lock, which driven by a spring and released by a pull of the trigger, falls and (usually via an intervening firing pin) strikes the detonating primer of the load and discharges the gun. Hammers may be external or internal.
Hammer Spur
  • The thumb-piece on the top rear of the hammer that enables it to be manually drawn back to full cock

  • A firearm with a coil-spring-actuated firing pin, or with its hammer enclosed inside the action body; i.e.. no externally visible hammer.

  • A revolver or pistol design that actually have hammers but are fully encased inside the frames, hammer designs where the spurs have been removed for concealment, or striker-fired pistols that are truly hammerless.

  • In any mechanism, a small lever that engages a notch to actuate movement in one direction only. Specifically, a small spring-loaded lever attached to the hammer of a revolver which actuates the cylinder to advance one increment and move the next chamber into battery as the hammer is cocked. Also: Pawl
  • (British) - The wrist, or the grip of a long gun.
Hand Detachable Locks
  • The firing mechanism of a break-open gun which may be removed for inspection or cleaning without the use of tools. The release latch may be plainly visible or concealed. A feature typically seen on sidelock guns but also on the Westley Richards "droplock" boxlock action.  

noun hand·gun \-ˌgən\

  • Synonym for pistol. designed to be fired while held in one or both hands, rather than while braced against the shoulder.
  • A small, short-barreled firearm, possibly small enough to be concealed on the person, and able to be held and discharged in one hand. The term includes antique dueling pistols, modern single-shot, semi-automatic pistols and revolvers.
  • Cartridges assembled by an individual person from the individual components (primer, shell casing, gunpowder, and bullet) and are typically tailored specifically for their firearm.

  • Handloading - The process of assembling cartridge case, bullet or shot, wads and primer to produce a complete cartridge with the use of hand tools in the interest of loading for firearms for which cartridges are not available, experimenting with loads to achieve better performance, or to save money. Not to be attempted without knowledgeable instruction and careful study of the process.

  • German for Hand-Cocking or Cocker/De-Cocker. A type of action on a break-open gun or rifle where, in place of a traditional top tang safety, a somewhat more robust tab is fitted. Normally such a gun is carried in the field loaded, but with the action not cocked---an exceedingly safe condition. Then, when ready to fire, the shooter, instead of pushing a safety tab forward, pushes this larger tab forward, cocking the mainspring, making the gun ready to fire. Then, if the shot is not taken, he may simply slide this tab rearwards again, de-cocking the gun and returning it to the still-loaded, but very safe position.
Hang Fire
  • A dangerous situation resulting occasionally from the use of outdated old ammunition where the primer does not fire instantly upon being struck by the firing pin. The cartridge may fire in a virtual instant or some seconds later. In the event that a cartridge fails to fire immediately upon the pull of the trigger, always count out ten seconds before opening the breech.
Hanging Tag
  • The manufacturer's descriptive tag, tied to the trigger-guard of a brand new gun on the dealer's sales rack. For such ephemera to have survived in the company of an older gun is both unusual and a small indication of the care it has enjoyed since new.


A popular designation for the 230-grain full metal jacketed round-nosed military load for the .45 ACP. By extension, loads using similar bullets in the other auto pistol calibers. Hardball, a slang term used for full metal jacket bullet pistol ammunition, particularly in .45 ACP caliber. The full metal jacket (FMJ) or full metal case (FMC) bullet is also known as "hardball." The FMJ is almost entirely encased in a jacket of a reasonably malleable metal (usually copper) harder than the bullet's core (which is usually composed of soft lead).

.45 Hardball Ammunition
.45 Hardball Ammunition


















  •  Head [of a Stock] - The forward end of a buttstock, where it meets the receiver and accepts the bulk of the gun's recoil when fired.
  • The distance, or clearance, between the base of a chambered cartridge and the breech face (or bolt face) of a firearm. This is a critical dimension, particularly in high powered rifles. If there is too little headspace, the bolt will not close. If there is too much headspace the cartridge will not be properly supported in the chamber and the cartridge will expand upon firing and may rupture, blasting high-pressure gas into the action and possibly into the body of the shooter. Headspace should be .003" - .006" in a centerfire rifle. It can be checked with a set of "Go and No-Go" gauges specific to the calibre in question. (See below.) With a standard cartridge, the headspace is registered by the shoulder, with a belted cartridge, the headspace is registered by the forward edge of the bel
Headspace Gauge
  • Plugs of hardened steel, precisely machined in relation to the standard dimensional specifications of a given cartridge, normally in sets of three: "GO", "No-Go" and "Field". By loading these plug-gauges into the chamber in succession, one can check that the action should close on the "Go" gauge. It should not close on the "No-Go" gauge---but might were enough force to be used. And, it absolutely should not close on the "Field" gauge.
  • Markings impressed into the base of a cartridge case, normally identifying the maker's name, the cartridge caliber designation, and sometimes the date.
Heat Treating
  • A process to achieve the desired balance between hardness and resilience for the intended purpose of the metal. First, the steel is heated to above its austenitic temperature (around 1800°F depending on the alloy; incandescent orange, and no longer attracted by a magnet). Then, is quenched in water or oil to cool it as rapidly as possible. Now, exceptionally hard and too brittle for most applications, it is re-heated to a specific lower temperature than before and quenched again, relieving the desired amount of its hardness.
Heavy Trigger
  • A trigger that requires a lot of pressure to pull it past the break point. Rifles tend to have considerably lighter triggers than handguns, and even a heavy rifle trigger is often lighter than a light handgun trigger.


Heel (of a rifle gun stock)

  • The top of the butt, when the gun is in position on the shoulder to be fired, is called the heel.

  • The top of the butt-end of a gun stock
Heel And Toe Plates
  • Protective plates, usually of steel or horn, covering the top and bottom of a gunstock's butt only (the heel and the toe); leaving wood exposed in the center.
  • A compact Germanic falling block single shot action developed ca 1880, which both opens and cocks when the front of the triggerguard is pulled downwards, and which incorporates an integral cocking/de-cocking mechanism.
High Brass

  • By convention, powerfully loaded shotgun cartridges for hunting are generally manufactured with relatively longer brass end-caps than lower powered cartridges intended for target shooting. While different-sized brass bases are of virtually no consequence to the strength of the shell in relation to the steel breech of the gun itself, they do help the shooter identify the relative power of cartridges at a glance.
High Capacity Magazine
  • An inexact, non-technical term indicating a magazine holding more rounds than might be considered "average."

High Kneeling
  • A shooting position in which one or both knees are touching the ground, but the shooter is otherwise erect.

Hinge Pin

Hinge Pin

  • A short cylindrical rod of hardened steel running laterally near the front of the bar of a break-open gun's action around which the barrel hook revolves when the gun is opened. Over the decades, this pin and its complimentary hook can wear and a gun can sometimes "shoot loose" or "come off the face." The proper cure for this condition is to replace the hinge pin with a new one, slightly oversized, to compensate for wear on both itself and on the barrel hook.
  • Hornady Magnum Rimfire, a type of ammunition.


A comic term for a Colt Single Action Army or similar revolver. A large caliber revolver.   A firearm, ie., old western 6 shot revolvers. shaped like a part of a hogs leg. slang for a pistol, western style. Any large caliber handgun, typically with a long barrel.

Modern Hogleg RevolverModern Hogleg Revolver                                                         Old West HoglegOld West Hogleg

Holdopen Toplever

Holdopen Toplever

  • A catch built into the receiver of a break-open gun to keep the toplever in its extreme right position when the barrels are removed. This device makes it slightly easier to remount the barrels. As the barrels are mounted and the breech closed, the barrels contact some kind of release pin and the toplever automatically returns to the center locked position. Because, however, it requires a separate act to find and to depress this tiny tab to re-center the toplever on a broken-down gun, this feature may be irritating when trying to put a gun away in its case.
Hollow Point Bullet
  • A bullet with a concavity in its nose to increase expansion on penetration of a solid target. some hollow-point's are also designed to fragment as they expand. They are least likely to over-penetrate the target and harm an innocent bystander. Commonly used for self-defense.
  • A bullet type with a concavity at its tip, designed to promote expansion upon hitting a solid target.

noun hol·ster \ˈhōl-stər\

  • A gun holder that may be strapped to a human body, or affixed to the inside of a pack or bag, or dropped into a pocket. A holster serves to protect the gun's mechanisms and finish, to provide security by covering the trigger so it cannot be pulled inadvertently, and to present the grip of the gun at a constant angle for easy access. Some holsters also serve to obscure the outline of the gun so it may be more easily concealed. Typically made from leather or in plastic.



  • A hollow cylinder fitted to a rifle's front sight ramp, both to protect the delicate front sight bead from impact, and to shade it from oblique sunlight which could have the effect of altering the sight's apparent position.


  • A concave, semi-cylindrical surface cut into the forward lump of a barrel set of a break-open firearm which revolves about the hinge-pin when the gun is opened.


  • The forward-most part of a sidelock gun's stock; the slender flutes of wood extending along the lockplates, heading up to the receiver body. Also: Fingers
Hot Range
  • Pistol can be carried loaded, also a range where the range master has given the order to commence fire
Howdah Pistol

Howdah Pistol

  • Normally, a break-open, double-barrel, side-by-side pistol of large calibre, used by a maharaja when hunting tiger on the back of his elephant (in the howdah---the basket compartment in which he sits). The howdah pistol is the weapon of last resort in case the tiger tries to join him in the howdah.
Inertial Firing Pin

Noun (ĭ-nûr′shə)

A firing pin that is too short to contact the cartridge's primer when the hammer is resting on it and can only hit the primer when driven forward under the momentum of the hammer blow. The system used in the Colt 1911 is an example of an inertial firing pin.

1911 showing internal firing pin
1911 showing internal firing pin

























International Practical Shooting Confederation. The governing body for much of the action/combat shooting competition conducted worldwide. Often used as a term for this type of competition. IPSC's American affiliate is the United States Practical Shooting Association (Dept. GAH, Box 811, Sedro Woolley, WA 98284)

International Practical Shooting Confederation
International Practical Shooting Confederation















Jargon is a type of language that is used in a particular context and may not be well understood outside of it. The context is usually a particular occupation (that is, a certain trade, profession, or academic field), but any ingroup can have jargon.

JHC Jacketed Hollow Cavity

Stands for Jacketed Hollow Cavity, a proprietary name used by Sierra Bullets for their line of Jacketed Hollow Point bullets.

Sierra Bullets Jacketed Hollow Point bullets
Sierra Bullets Jacketed Hollow Point bullets

JHP Jacketed Hollow Point

Stands for Jacketed Hollow Point, a bullet similar to a Jacketed Soft Point, except that a portion of the nose cavity is hollowed out for greater bullet expansion. A hollow-point bullet is an expanding bullet that has a pit or hollowed out shape in its tip, often intended to cause the bullet to expand upon entering a target in order to decrease penetration and disrupt more tissue as it travels through the target. It is also used for controlled penetration, where over-penetration could cause collateral damage (such as on an aircraft).

.357 Magnum rounds. Left: Jacketed Soft Point (JSP) round. Right: Jacketed hollow-point (JHP) round. JSP is a semi-jacketed round as the jacket does not extend to the tip.

JSP Jacketed Soft Point

Stands for Jacketed Soft Point, a type of bullet with a soft lead core enclosed by a hard metal jacket (usually an alloy of copper), but with the nose section exposed to ensure bullet expansion.

Jacketed Soft Point
Jacketed Soft Point
K Frame

Most firearms makers have special designations for their various frame sizes, but only the Smith & Wesson revolver frame designations seem to be in general currency these days. Modern Smith & Wesson revolvers are made on four sizes of frames: the J (small), K (medium), L (medium-large) and N (large). Formerly there was the I frame, superseded by the slightly longer J frame, and many years ago the petite .22 "Ladysmith" revolvers were made on an M frame.  The K-Frame revolver is one of the most important innovations in Smith & Wesson history and was built specifically to handle the .38 S&W Special cartridge. Since its introduction, the K-Frame has been a favorite for military and police professionals as well as target shooters and enthusiasts. Today's K-Frame is available in .22 LR and .38 S&W Special.

Smaith & Wesson K Frame revolvers
Smaith & Wesson K Frame revolvers

Kentucky Windage

N. (kən-tŭk′ē)  (wĭn′dĭj)

Kentucky Windage is the practice of applying a horizontal adjustment of the point of aim for wind (windage) without the use of any physical or mechanical adjustments on the weapon. A windage correction made by aiming a firearm to the right or left of the target rather than by adjustment of the sights. or An adjustment made by a shooter to correct for wind (or motion of the target) by aiming at a point horizontal to the target's position in the sight rather than by adjusting the sight to compensate.

Kentucky Windage Kentucky Windage Reading the Wind Reading the Wind

Locked Breech

(lŏk)                         (brēch)

A firearms action in which the barrel and breechface remain locked together during the initial part of the firearm's discharge. Most powerful auto pistols use the locked-breech principle; most low-powered ones are blowbacks. Recoil operation is an operating mechanism used in locked-breech, autoloading firearms. As the name implies, these actions use the force of recoil to provide energy to cycle the action.

Locked Breech Pistol
Locked Breech Pistol

Noun (măg′ə-zēn′, măg′ə-zēn′)

A holder for cartridges to be fed into the chamber of a firearm. Usually, but not always, detachable in handguns. (Cf. CLIP) , A compartment in some types of firearms, often a small detachable box, in which cartridges are held to be fed into the firing chamber.

Pistol MagazinePistol MagazineRifle MagazinesRifle Magazines

Magazine Safety

[¦mag·ə¦zēn ′sāf·tē]

Also called a "magazine disconnector." A device that prevents a pistol from being discharged when the magazine is removed. A mechanism for an automatic pistol, to make firing impossible unless the weapon contains the magazine.  A magazine disconnect is an internal mechanism that engages a mechanical safety such as a block or trigger disconnect when the firearm's magazine is removed  (Warning: These devices are not always reliable.)

Magazine disconnect
Magazine disconnect


Noun  (mān′sprĭng′) or (ˈmeɪnˌsprɪŋ)

The spring that powers a handgun's firing mechanism. The mainspring is that spring on (or in) a gun which does the job of causing the gun to fire. That is, while other springs are often used and are also integral, the mainspring is truly the main spring in that it performs the most important function.

The mainspring is the spring which causes a gun's hammer and/or firing pinto fall and/or travel forward under spring-exerted pressure.

On guns which lack a hammer, such as striker-fired pistols and bolt action rifles, the spring which drives the firing pin is often simply called the firing pin spring, which is correct - but it can also be correctly called the mainspring.

Revolver MainspringRevolver MainspringPistol MainspringPistol Mainspring

Necking Down

[′nek·iŋ ¦dau̇n]

Refers to shrinking the neck of an existing cartridge to make it use a bullet of a different caliber. A typical process used in the creation of wildcat cartridges.

Necking Down Cartridges Necking Down Cartridges

Out of Battery

The status of a weapon before the action has returned to the normal firing position. The term originates from artillery, referring to a gun that fires before it has been pulled back into its firing position in a gun battery. In firearms where there is an automatic loading mechanism, a condition in which a live round is at least partially in the firing chamber and capable of being fired, but is not properly secured by the usual mechanism of that particular weapon can occur.

Bullet out of battery Bullet out of battery


foreign term si vis pa·cem, pa·ra bel·lum \sē-ˈwēs-ˈpä-ˌkem ˈpä-rä-ˈbe-ˌlm\

Means "prepare for war." From a Latin maxim--si vis pacem, para bellum--"If you want peace, prepare for war." The European designation of the Luger pistol and (today more commonly) the 9mm cartridge it chambered. Parabellum MG14, a 7.92mm-calibre World War I machine gun, Pistol Parabellum or Luger P08 pistol, 7.65×21mm Parabellum, a handgun cartridge, 9×19mm Parabellum, a handgun cartridge



Noun   (pēs′mā′kər)

Originally, a dueling pistol. In contemporary usage, a Colt Single Action Army revolver or a derivative. The Colt Single Action Army — also known as the Model P, Peacemaker, M1873, Single Action Army, SAA, and Colt .45 — is a single action revolver with a revolving cylinder holding six metallic cartridges. It was designed for the U.S. government service revolver trials of 1872 by Colt's Patent Firearms Manufacturing Company, today Colt's Manufacturing Company, and was adopted as the standard military service revolver until 1892.

Colt Peacemaker
Colt Peacemaker
Pin Gun

A heavily customized auto pistol with a muzzle extension that serves as a weight and recoil compensator. Origninally developed for bowling pin shooting, hence the name. Now universally used in action shooting sports.

Modified Pin Gun
Modified Pin Gun



Originally, any firearm designed to be fired one-handed. In contemporary American usage, the term "pistol" is limited to handguns in which the barrel and chamber form a single unit, i.e., self-loaders and single shots. It is considered erroneous to apply the term "pistol" to a revolver.

However, this distinction is of fairly recent origin. Colt referred to its revolvers as "pistols" at least into the 1880's, and the British military officially designated their service revolvers as "pistols" as late as the WWII era. The origin of this word is particularly obscure. Some trace it to the Italian town of Pistoia, an early gunmaking center. Another explanation derives from a Bohemian handgun called a "pist'ala" from a Czech word for "pipe." Several other more fanciful etymologies exist.

Colt 1911 Semi-Auto Pistol
Colt 1911 Semi-Auto Pistol

May mean either lowering the ejection port of a self-loading pistol to ensure greater reliability and less damage to cases or the practice of drilling gas vents in a barrel to reduce muzzle jump. The proprietary Mag-na-port system is a well-known example of this.

Revolver Muzzle Porting
Revolver Muzzle Porting


Stands for Practical Pistol Course, a course of fire developed by the FBI that involves shooting at man-silhouettes from a variety of ranges and shooting positions. Shot competitively, usually by police. The custom heavy-barreled revolvers favored in these competitions are known as "PPC revolvers."

In the late ‘30s, in an effort to improve and make its firearms training more realistic, the FBI introduced the Practical Pistol Course (PPC). The course encompassed prone shooting at 60 yards, sitting and barricade positions at 50 yards, kneeling and barricade shooting at 25 yards, off-hand shooting at 15 yards and point shooting using the “FBI Crouch” at 7 yards. The course was timed to add an element of stress, and the targets were humanoid silhouettes instead of the traditional round bulls-eye.


Quad barrelled



A gun, typically artillery, with four barrels. There are some modern Handguns, Rifles, and Shotgun with four barrels.

Quad Barrelled .357 Handgun Quad Barrelled .357 Handgun                                           Quad Barrelled Shotgun Quad Barrelled Shotgun

Recoil Operated

intr.v (rĭ-koil′)

A form of locked-breech semi-automatic operation in which the barrel and breech remain locked together during the peak pressure, then move rearward under recoil to effect unlocking. Most high-power pistols use this system. Recoil operation is an operating mechanism used in locked-breech, autoloading firearms. As the name implies, these actions use the force of recoil to provide energy to cycle the action. In a recoil-operated handgun the barrel moves a short distance with the slide when the gun is fired and the bullet is still in the barrel. Other operating systems are Blow forward operated, blowback operated, gas operated, and chain.

Recoil Operated Pistol Recoil Operated Pistol

Recoil Shield

On a revolver, a lateral extension of the standing breech, to each side, to prevent fired or unfired cartridges from coming out of the chambers and to protect the otherwise exposed primers of unfired cartridges. The enlarged portion of a revolver's frame immediately behind the cylinder.

Revolver Recoil Shield
Revolver Recoil Shield
Recoil Spring

The spring that returns a self-loading firarm's action into battery after firing.

Auto Pistol Recoil Spring
Auto Pistol Recoil Spring


Noun (rĭ-vŏl′vər)

Any handgun whose cartridges are contained in a multi-chambered revolving cylinder separate from the barrel. (Cf. PISTOL) A firearm, usually a handgun, with a cylinder having several chambers so arranged as to rotate around an axis and be discharged successively by the same firing mechanism through a common barrel.  A handgun having a revolving cylinder with several cartridge chambers that may be fired in succession. A pistol having a revolving multichambered cylinder that allows several shots to be discharged without reloading.

Smith & Wesson Revolver 460 Smith & Wesson Revolver 460 Smith & Wesson Revolver M&P Smith & Wesson Revolver M&P



The portion of a firing mechanism that holds a hammer or striker cocked. The catch in a gunlock that keeps the hammer halfcocked or fully cocked. A part which retains the hammer or striker in the cocked position. When released, it permits firing.

Trigger Sear
Trigger Sear (3)
Semi Wadcutter

Semi-Wadcutter (SWC)

A semiwadcutter or SWC is a type of all-purpose bullet commonly used in revolvers. The SWC combines features of the wadcutter target bullet and traditional round nosed revolver bullets, and is used in both revolver and pistol cartridges for hunting, target shooting, and plinking. A bullet with a flat-ended nose section and a full-caliber cutting shelf.

The designs of Elmer Keith are famous examples of semi-wadcutter bullets.  SWC rounds are often used for heavy loads intended either for hunting or for self-defense. Some SWC bullet designs have a smaller diameter rear end, making these bullets suitable for use with gas checks. Properly lubricated SWC bullets with gas checks are suitable for use at velocities exceeding 1700 ft/s (518 m/s), the gas check preventing leading of rifling.

Keith Style 45 SWC
Keith Style SWC with one crimping groove and one filled lubrication groove.

Silhouette Shooting

(sĭl′o͞o-ĕt′)   [ˈʃuːtɪŋ]

The competitive sport of knocking over metallic silhouettes of animals with a rifle or handgun, usually at relatively long ranges. Metallic silhouette shooting is a group of target shooting disciplines that involves shooting at steel targets representing game animals at varying distances. Metallic silhouette shooting can be done with airguns, black-powder firearms, modern handguns, or modern rifles.

Metallic silhouette shooting
Metallic Silhouette Shooting

Single Action

[′siŋ·gəl ′ak·shən]

A method of fire in some revolvers and shoulder arms in which the hammer must be cocked by hand, in contrast to double action inwhich a single pull of the trigger both cocks and fires the weapon. In revolvers, any gun whose hammer must be manually cocked for each shot. In semi-automatic pistols, any pistol where the hammer or striker must be manually cocked before the first shot can be fired.

Single Action Revolver, Ruger Single Action Revolver, Ruger

1873 single action Rifle and Revolver 1873 single action Rifle and Revolver


( sŏft′-)

A target shooter's term for light, target loads for the .45 ACP. (Cf. HARDBALL)

.45 ACP Softball Ammo .45 ACP Softball Ammo

Specialty Pistol

A large, long-barreled pistol, nearly always a single-shot, capable of chambering cartridges hitherto appropriate only for rifles. Usually intended for hangun hunting or metallic silhouette shooting.

Specialty Pistols Specialty Pistols 



An axially mounted, spring-propelled firing pin. Any part in a mechanical device that strikes something, such as the firing pin of a gun. A firing pin or a projection on the hammer of a firearm, which strikes the primer to initiate a propelling charge explosive train or a fuse explosive train.

Striker style Firing Pin Striker style Firing Pin

The 1911


The Colt-Browning United States Government Model of 1911 .45 automatic pistol. Loosely, any pistol that uses the same design. Designed by John Browning, the 1911 is the best-known of his designs to use the short recoil principle in its basic design. The pistol is widely copied, and this operating system rose to become the preeminent type of the 20th century and of nearly all modern centerfire pistols.

Colt Delta Elite 1911 Colt Delta Elite 1911 (10mm) ;Colt 1911Colt 1911 in .45 ACP;


The practice of polishing, enlarging and recontouring the feed ramp of an auto pistol's barrel to ensure more reliable functioning, especially with semi-wadcutter and other non-standard bullets.

Enlarging the Feed Ramp Enlarging the Feed Ramp Throating of feed ramp Throating of feed ramp

TMJ Or Total Metal Jacked

Stands for Total Metal Jacketed, a term used by Speer to describe the full-metal-jacketed bullets in which even the base is jacketed. Total metal jacket bullets, often referred to simply as "TMJ", are the most widely used bullet type at indoor ranges and among competitive shooters. The reason for this is a simple one but important: The normal full metal jacket or FMJ bullet has a small amount of exposed lead at the base of the bullet while the TMJ does not. The TMJ surrounds the otherwise exposed lead area with copper.

FMJ vs TMJ FMJ on the LEFT vs TMJ on the RIGHT

Transfer Bar

A revolver safety mechanism that delivers the force of the hammer blow to the firing pin by means of an intermediary piece of metal that rises into firing position only when the trigger is pulled.

Revolver Transfer Bar Revolver Transfer Bar

Trigger Break

[trig-er]   [breyk]

  • The point at which the trigger allows the hammer to fall, or releases the striker, so that the shot fires. The ideal trigger break is sudden and definite. "Like a glass rod" is the cliché term shooters use to describe the ideal crisp, clean break.
Trigger Job

A process of lightening and otherwise improving trigger pull by means of polishing and reshaping the engagement surfaces. Can be dangerous unless performed by a qualified gunsmith. A trigger job usually involves polishing, and in some cases squaring off the engagement surfaces of the sear and hammer, along with other surfaces that are involved in the action of pulling the trigger in order to smooth it up.

This is usually done by a gunsmith because they have the proper tools and know which areas need to be touched up as well as having the knowledge as to how much to remove without making the gun unsafe.

Trigger Job Trigger Job


A sliding bar, running longitudinally through the watertable of a break-open side-by-side gun's action, with openings through which the lumps of the barrels pass when the gun is closed. Under spring tension, this bar moves forward when the opening control is released and its two locking surfaces engage complementary slots (bites) in the rear of the two barrel lumps. Originally operated by a hinged tab in front of the trigger guard. Now invariably operated by a cam from Scott's [toplever] spindle. Most modern side-by-side guns lock closed in this manner. Developed by Purdey

Shotgun Underbolts Shotgun Underbolts

Varmint Rifle

(vär′mĭnt)  (rī′fəl)

An American English term for a small-caliber firearm or high-powered air gun primarily used for varmint hunting — killing non-native or non-game animals.

Varmit Rifle Varmit Rifle


Wadcutter (WC)

A flat-ended, nearly cylindrical bullet designed for cutting full-caliber holes in targets. Especially favored in light, target loads. A wadcutter is a special-purpose flat-fronted bullet specially designed for shooting paper targets, usually at close range and at subsonic velocities typically under approximately 900 ft/s (274 m/s).

Wadcutters have also found favor for use in self-defense guns, such as .38 caliber snub-nosed revolvers, where due to short barrel lengths, maximum bullet velocities are usually low, typically under 900 ft/s (274 m/s), and improved lethality is desired. Wadcutters are often used in handgun and airgun competitions.

Wadcutter .38cal Wadcutter .38cal


A term coined by gunwriter Robert T. Shimek to denote the modern breed of 9mm Parabellum auto pistols of recent design, usually featuring high magazine capacity and a double-action trigger mechanism or other modern ignition system (e.g., the squeeze-cocker of the Heckler & Kock P7 series or the Safe Action of the Glock).

Wonder Nine refers to any semi-automatic pistol that is chambered in 9×19mm Parabellumand has a staggered column magazine, as well as a double-action trigger for at least the firstshot.  The term was coined by firearms author Robert Shimek, and became popular in Americanfirearm-related magazines during the 1980 by those advocating for their use by police forces.

HK P7 HK P7 Wondernine

X Rng

A circle in the middle of a shooting target bullseye used to determine winners in event of a tie.

The X-ring in a Target The X-ring in a Target



The heading of a bullet, used in external ballistics that refers to how the Magnus effect causes bullets to move out of a straight line based on their spin.

Bullet Yaw Effect Bullet Yaw Effect

Zero In

(zîr′ō, zē′rō)

(Firearms, Gunnery, Ordnance & Artillery) a gunsight setting in which accurate allowance has been made for both windage and elevation for a specified range. The act of setting up a telescopic or other sighting system so that the point of impact of a bullet matches the sights at a specified distance.

Zero in a Sight Zero in a Sight