Archives: Glossary

A circumferential bulge in a barrel typically caused by firing into an obstructed bore. See also Bulged Barrel.

A butt plate, usually of rubber, to reduce the sensible recoil of shoulder firearms.

A device for measuring Free Recoil Energy in which a firearm is suspended from fixed points so as to allow it to swing freely while the barrel remains horizontal.

1. Steel insert in the frame of a revolver immediately surrounding the firing-pin hole; also called Firing-Pin Bushing. 2. See Lug, Recoil.

On a revolver, a lateral extension of the standing breech, to each side, to prevent fired or unfired cartridges from coming out of the chambers and to protect the otherwise exposed primers of unfired cartridges.

A spring used to store some recoil energy and subsequently close the action and feed the next round in semiautomatic firearms. In other designs, a recoil spring may serve to absorb recoil energy or perform other functions.

A less than nominal powder charge.

Ammunition used to qualify and/or calibrate velocity and pressure measuring systems.

The adjusting of the relationship of the axes of multi-barreled firearms so as to make the points of impact coincide at a given distance.

An unconventional mechanism generally found only in some trap shotguns in which the firearm is fired by the release of, rather than the pull of, the trigger.