Letter: B

A rectangular receptacle attached to or inserted into a firearm that holds cartridges stacked on top of one another ready for feeding into the chamber.

An ignition component consisting of a cup, explosive mixture, anvil and covering foil or disc which together form the completed primer ready for assembly into the primer pocket of a cartridge case. One central flash hole is pierced through the bottom of the primer pocket into the propellant cavity of the case. Used in modern commercial centerfire ammunition made in Canada and the United States.

The end of the barrel where the ignition of the propellant takes place.

The locking and cartridge head supporting mechanism of a firearm that operates in line with the axis of the bore.

A fixture having a small centrally located aperture that fits into a firearm chamber. Used in conjunction with a similar device that fits into the muzzle to establish the axis of the bore.

That part of the action which is against the head of the cartridge case or shotshell when in battery.

In percussion or flintlock firearms, the metal part that is threaded into the breech end of the barrel.

That part of the frame of a revolver or break-open firearm which supports the head of the cartridge when it is fired.

A mechanism which does not operate in line with the axis of the bore, and which is intended to support, properly, the head of the cartridge.

A misnomer. Commonly confused with headspace.