forensic fact story

vocabulary

Action-> the part of the firearm that loads, fires, and ejects a cartridge. Includes lever action, pump action, bolt action, and semi-automatic.

Barrel->the metal through which the bullet is fired.

Black powder-> the old form of gunpowder invented over a thousand years ago and consisting of nitrate, charcoal, and sulfur.

Bore->the inside of the barrel. "Smoothbore" weapons (typically shotguns) have no rifling, most handguns, and rifling, most handguns and rifles have "rifling"

Breech->the end of the barrel attached to the action.

Butt or stock->the portion of the gun, which is held or shouldered.

Bullets->the projectile. They are shaped or composed differently for a variety of purposes.

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

Cartridge->also called a "round", "ammunition", or "shell". Made up of a case, primer, powder, and bullet.

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

Chamber->the portion of the "action" that holds the cartridge ready for firing.

Choke->a constriction of a shotgun bore at the muzzle that determines the pattern of the fired shot.

Double action->pulling the trigger both cocks the hammer and fires the gun.

Double barrel-> two barrels side by side or one on top of the other, usually on a shotgun.

Gauge->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).

Hammer-> a metal rod or plate that strikes the cartridge primer to detonate the powder.

Ignition-> how the powder is ignited, old muzzle-loading weapons use flintlock or percussion caps. Modern guns use "primers" that are "rimfire" or "centerfire".

Lands and grooves-> lands are the metal inside the barrel left after the spiral grooves are cut to produce the rifling.

Magazine->a device for storing cartridges in a repeating firearm for loading into the chamber. Also referred to as a clip.

Magnum->an improved version of a standard cartridge that uses the same caliber and bullet, but had more powder, giving the fired bullet more energy. Magnum shotgun loads, however, refer to an increased amount of pellets in the shell.

Muzzle->the end of the barrel out of which the bullet exits.

Pistol-> synonym for a handgun that does not have a revolving cylinder.

Powder->modern gun cartridges use "smokeless" powder that is relatively stable, of uniform quality, and leaves little residue when ignited.