Unit 5: Firearm Terminology

The part of a firearm that loads, fires, and ejects cartridges. It includes lever (single-shot), pump (single-shot), bolt (single shot) actions, and semi-automatic (repeater w/ out manual operation). “Repeaters” (can shoot multiple rounds) include all of these actions. Fully automatic actions are used in machine guns.

The metal tube through which the bullet is fired.

The old form of gunpowder invented over 1,000 years ago and consisting of nitrate, charcoal, and sulfur.

The inside of the barrel. “Smoothbore” weapons (typically shotguns) have no rifling. Most handguns and rifles have “rifling.”

The end of the barrel attached to the action.

The portion of the gun, which is held or shouldered.

The projectile. They are shaped or composed differently for a variety of purposes.

The end of the bullet is round.

There is a hole in the bullet that creates expansion when a target is struck, creating more damage.

The soft lead is partially surrounded by another metal, usually copper, that promotes exit velocity.

The soft lead is surrounded by another metal, usually copper, that allows the bullet to penetrate a target more easily.

The front of the bullet is flattened. Used mainly for target practice.

The diameter of the bore measured from land to land, usually expressed in hundredths of an inch (.22 cal) or in millimeters (9mm).

Also called a “round,” “ammunition,” or “shell.” Made up of a case, primer, powder, and bullet.

The cartridge contains the primer in the center of the base, where it can be struck by the firing pin of the action (most commonly on a 22 cal).

The portion of the “action” that holds the cartridge ready for firing.

A constriction of a shotgun bore at the muzzle that determines the pattern of the fired shot.

Pulling the trigger both cocks the hammer and fires the gun.

Two barrels side by side or one on top of the other, usually on a shotgun.

Refers to the diameter of the barrel on a shotgun, in terms of the number of lead balls the size of the bore it would take to weigh one pound (10 gauge, 12 gauge, etc.)

A metal rod or plate that strikes the cartridge primer to detonate the powder.

The way in which powder is ignited. Old muzzle-loading weapons used flintlock or percussion caps. Modern guns use “primers” that are “rimfire” or “centerfire.”

Lands are the metal inside the barrel left after the spiral grooves are cut to produce the rifling.

A device for storing cartridges in a repeating firearm for loading into the chamber. Also referred to as a “clip.”