Glossary of Firearms Terms - M

M

• machine gun: a fully automatic mounted or portable firearm.

• machine pistol: a handgun-style fully automatic or burst-mode firearm.

• machine revolver: a revolver that uses the energy of firing for cocking the hammer and revolving the cylinder, rather than using manual operations to perform these actions (more correctly, a semi-automatic revolver).

• magazine: A magazine is an ammunition storage and feeding device within or attached to a repeating firearm. Magazines may be integral to the firearm (fixed) or removable (detachable). The magazine functions by moving the cartridges stored in the magazine into a position where they may be loaded into the chamber by the action of the firearm.

• match grade: Firearm parts and ammunition that are suitable for a competitive match. This refers to parts that are designed and manufactured such that they have a relatively tight-tolerances and high level of accuracy.

• muzzle: The part of a firearm at the end of the barrel from which the projectile will exit.

• muzzle brakes and recoil compensators: devices that are fitted to the muzzle of a firearm to redirect propellant gases with the effect of countering both recoil of the gun and unwanted rising of the barrel during rapid fire.

• muzzle energy is the kinetic energy of a bullet as it is expelled from the muzzle of a firearm. It is often used as a rough indication of the destructive potential of a given firearm or load. The heavier the bullet and the faster it moves, the higher its muzzle energy and the more damage it will do.

• muzzle velocity is the speed at which a projectile leaves the muzzle of the gun. Muzzle velocities range from approximately 800 ft/s (240 m/s) for some pistols and older cartridges to more than 4,000 ft/s (1,200 m/s) in modern cartridges such as the .220 Swift and .204 Ruger. In conventional guns, muzzle velocity is determined by the quality (burn speed, expansion) and quantity of the propellant, the mass of the projectile, and the length of the barrel.