Letter: A

A device in break-open firearms which expels fired cases when the action is opened.

A system for reloading a firearm utilizing some of the energy realized from firing a cartridge.

A common but improperly used term applied to autoloading pistols in use today. Most current “automatic” pistols are truly semiautomatic in action only. See Semiautomatic.

A code number and/or letter(s) usually found on the carton that identifies a particular quantity of ammunition for its manufacturer.

A fully automatic shoulder firearm that starts firing when the trigger is pulled and continues until the trigger is released or ammunition is exhausted. The term should not be used in conjunction with semiautomatic firearms. See Semiautomatic.

A method of distinguishing various gauges of shotshells and types of metallic ammunition by color or plating.

A safety device on some firearms intended to return to the On position when the action is opened.

A continuously produced batch of ammunition uniquely identified by a code. Lot size is determined by the manufacturer as part of their manufacturing process.

An adapter that, when installed in a gun chamber for which it was designed, permits a smaller cartridge to be fired in the gun.

The angle formed between a horizontal line and the center line of the bore at the moment the projectile leaves the muzzle of the gun.