drum magazine

An example of a "Beta C-Mag" double drum design in use on M4 Carbine.‎

A drum magazine is a type of firearms magazine that is cylindrical in shape, similar to a drum. Instead of having rounds lay flat, as in a more common "box" magazine, in a drum magazine rounds are stored in a spiral around the center of the magazine.

The advantage over traditional box-shaped magazines is that a drum magazine can carry much more ammunition, often twice that of a box magazine, such as the 71-round drum for the Russian PPSh-41 submachine gun, without making it too big to be impractical to carry. The downside to drum magazines is that they are more prone to jamming, and increase the overall weight of the weapon in which they are being used.

The most famous example of a firearm using a drum magazine is the iconic 1930s-era Thompson submachine gun, which had both 50 and 100 round drum magazines available for it. The Thompson also had 20 and 30 round "box" magazines available, demonstrating the difference in carrying capacity between a box and a drum.

More recently "double drum" designs have come into greater use. Where normal magazines put rounds in two rows, in a "double drum" two drums resting on either side of the weapon each hold one row, the two of which combine into one row before entering the receiver. Examples are the World War II era MG 15, and the modern Beta C-Mag. These systems have the advantage of storing even more rounds than a regular drum, while improving the distribution of weight.

The drums of aircraft cannons such as the M61 Vulcan and GAU-8 Avenger resemble drum magazines for small arms, but function in a different manner. That is, the rounds are stored nose-facing-in, and are kept under positive control by partitions running the length of the drum, and are driven forward by a helical auger. This makes their operation very reliable, even when operated at rates of fire of several thousand rounds per minute.

Weapons capable of using drum magazines

• Atchisson Assault Shotgun (AA-12)
• AK-47
• AR-15
• Colt 9mm SMG
• Heckler & Koch G36
• Heckler & Koch HK33
• M-14 rifle
• M-16 Rifle
• M249 light machine gun
• MG 15
• PPSh-41
• Ruger Mini-14
• Saiga-12
• SIG SG 550
• Suomi KP/-31
• Thompson submachine gun
• Ultimax 100
• USAS-12

See also

• Magazine (firearm)

This firearms-related article is a stub. You can help Wikipedia by expanding it. v • d • e