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.