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