Letter J Firearms Glossary

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Jacket

A metal, usually copper, wrapped around a lead core to form a bullet.

Jam

A malfunction which locks up the gun so badly that tools are required in order to fix it. Sometimes used to denote a simple malfunction, but many people make a distinction between a complete jam and a simple malfunction.

Jaws

The vise-like device on a flintlock hammer used to hold the flint.

Jeweling

A cosmetic process to enhance the looks of firearm parts, such as the bolt. The look is created with an abrasive brush and compound that roughs the surface of the metal in a circular pattern.

JSP

Abbreviation for jacketed soft point

Jump

The amount of change in the bore axis, measured both vertically and horizontally, while the projectile moves from the chamber to the muzzle when it is fired.


14 Other Firearms Definitions You Need To Know


Safe

A firearm is said to be on safe when its safety is engaged and off safe when it is ready to fire.

Scattergun

A slang term for a shotgun.

Crosshairs

The cross-shaped object seen in the center of a firearm scope. Its more-proper name is reticle.

Hammer Spur

The thumb-piece on the top rear of the hammer that enables it to be manually drawn back to full cock.

Minute Of Angle

A 1/60th part of a degree, the unit of measure used in adjusting rifle sights. As it turns out conveniently, a minute of angle translates almost exactly to one inch at 100 yards (actually 1.047 inches), to two inches at 200 yards and three inches at 300 yards

Dry Fire

To pull the trigger and release the hammer of a firearm without having a cartridge in the chamber.

Cocked

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.

Stalking Safety

A safety catch fitted to a hammer gun where a sliding bar moves into a slot in the inner wall of the hammer base, locking it in place in the cocked position. The safety can then be released silently by sliding the tab, avoiding the game-startling sound of the hammer cocking.

Pan

The small dished container located on the side or top of a matchlock, wheel-lock or flintlock forearm used to hold the priming powder charge.

Elevation

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.

Backstop

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

CCP

Abbreviation for Concealed Carry Permit.

Holster

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.

Rimless

A cartridge in which the base diameter is the same as the body diameter. The casing will normally have an extraction groove machined around it near the base, creating a "rim" at the base that is the same diameter as the body diameter.