Magazine (firearms) - Function and Types

Function and Types

All cartridge based single barrel firearms designed to fire more than a single shot without reloading require some form of magazine designed to store and feed cartridges to the firearm's action. Magazines come in many shapes and sizes, with the most common type in modern firearms being the detachable box type. Most magazines designed for use with a reciprocating bolt firearm (tube fed firearms being the exception) utilize of a set of feed lips which stops the vertical motion of the cartridges out of the magazine but allow one cartridge at a time to be pushed forward (stripped) out of the feed lips by the firearm's bolt into the chamber. Some form of spring and follower combination is almost always used to feed cartridges to the lips which can be located either in the magazine (most removable box magazines) or built into the firearm (fixed box magazines). There also two distinct styles to feed lips. In a single feed design the top cartridge touches both lips and is commonly used in single column box magazines. A dual or alternating feed magazine consists of a wider set of lips so that the second cartridge in line forces the top cartridge against one lip. This design has proven more resistant to jamming in use with dual column magazines. Some magazine types are strongly associated with certain firearm types, such as the fixed "tubular" magazine found on most lever-action rifles and pump action shotguns. A firearm using detachable magazines may accept a variety of types of magazine, such as the Thompson submachine gun, which would accept box or drum magazines. Some types of firearm, such as the M249 and other squad automatic weapons, can feed from both magazines and belts.