Letter: A

A device found in some semiautomatic firearms that, through mechanical advantage or spring energy, transfers kinetic energy from one part of the mechanism to another with the resultant speeding up of the action.

A point on the target upon which the firearm is aimed.

A pneumatic device for measuring diameters.

A gun that uses compressed air or gas (e.g. carbon dioxide) to propel a projectile. Technical standards for air guns do not fall under the purview of the Sporting Arms and Manufacturers’ Institute.

A handgun with the same principle of operation as an air gun. Also called Pellet Pistol. See Air Gun.

The resistance of air to the passage of a projectile in flight.

The volume in a loaded cartridge or shotshell not occupied by the propellant or the bullet, wads or shot. Sometimes called Ullage.

The term used to describe the corkscrew-like flight path of a bullet.

The effect on velocity and, therefore, trajectory and shotshell pattern caused by changes in atmospheric density due to altitude.

One or more loaded cartridges consisting of a primed case, propellant and with or without one or more projectiles.