Letter: B

The distance that a bullet must travel from its position at rest in the cartridge case to its initial engagement of the rifling.

The tool used to lubricate bullets.

A reduction in the internal diameter of a firearm bore.

1. Rifled barrels: the minor interior diameter of a barrel which is the diameter of a circle formed by the tops of the lands. 2. Shotguns or muskets, the interior dimension of the barrel forward of the chamber but before any restrictive choke or expanded muzzle.

A method of aligning a barrel on a target by aiming through the bore. May be part of the sight alignment procedure.

An illuminated, optical device for examining the interior of the bore of a firearm.

An action commonly used in break-open firearms in which the hammer and hammer springs are located within the frame and are self-cocking.

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.