Letter: P

The kinetic energy of a projectile.

The spinning motion that is imparted to a projectile due to engagement with the rifling in the barrel of a firearm, as it is driven down the barrel. The rate of rotation is dependent upon the rate of twist of the rifling and the velocity. The barrel twist (left or right) determines the direction of the rotation.

A stamp applied at or near the breech or other stressed component of a firearm after it has passed a proof test.

The test of an assembled firearm or individual components by firing a Definitive Proof Cartridge. See Definitive Proof Cartridge.

In a firearm, the chemical composition which, when ignited by a primer, generates gas. The gas propels the projectile. Also called powder, gunpowder, smokeless powder, blackpowder.

A cartridge loaded to specified pressures higher than service loads to test barrels during manufacture, but before assembly.

A flexible device that is pulled through the barrel of a firearm to clean the barrel.

An action in which a moveable fore-end is manually actuated in a motion generally parallel to the barrel. This motion is transmitted to a breech bolt assembly which performs all the functions for loading and extracting cartridges. This type of action is prevalent in shotguns and is found to a lesser extent in rifles.

A type of front sight of triangular appearance. Also called Barleycorn Sight.

The insertion of a centerfire primer or battery cup in the head of a cartridge case or shotshell. Properly seated, it should be flush or below the face of the head.