Advantages of a Drum Mag

drum mag

A drum magazine (also called a double-drum magazine) is an ammunition feed system for a firearm. It holds multiple rounds in a rotating drum, with spring-driven rotors which advance them as the weapon is fired. Drum magazines increase ammunition capacity and range, while reducing the need for frequent reloading. They are however, heavy, bulky, and susceptible to jamming. They are also notoriously difficult to load, requiring the user to prop the magazine against a wall or surface and to use their body (torso, elbow, leg, etc) for support while they turn the magazine.

Drum mags require the user to wind their spring prior to each loading operation, and to remember to fully wind the magazine before storing it away. In addition, they are generally very sensitive to dirt and service abuse, and thus prone to failure or jamming.

The invention describes a drum magazine assembly 1 including an advancing mechanism or arm 106 and lever 104 assembly, which reduces these disadvantages of existing designs. The front cover assembly 10 includes an arm return spring 110 which helps to ensure the arm 106 returns to and/or remains biased towards a starting position after each advancing motion. This minimizes friction between cartridges or the drum and advancing arm, and improves feeding consistency and weapon reliability.

Another advantage of the drum magazine assembly 1 is that it may include a lever lock 1043 configured to prevent the lever 104 from being activated when the device is installed in a weapon. This helps to protect the weapon from damage by preventing accidental activation of the device, and can be especially beneficial when the device is being used in an environment where branches, debris, load bearing equipment, or the operator could inadvertently entangle or push on the lever 104.

In addition, the drum magazine assembly 1 may be configured to guide any debris passing through a viewing window (or opening) into non-critical areas, such as between the track ridge 501 and abutting sides 305 a, 305 b of the drum. This further minimizes undesirable friction between cartridges or the advancing arm 106 and the abutting sides, and increases cartridge feed consistency and weapon reliability.

Drum magazines are not as common as the more standard, high-capacity stick magazines for semi and full auto firearms. This is due to the fact that they are very difficult to load and can be subject to problems with spring resistance building up during loading operations. Typically, users must either load each cartridge individually by turning the magazine “tower” or open up a hatch and load them into the tracks of the drum, both of which are time-consuming and labor intensive. Despite this, they remain an option for those who prefer the extra ammo capacity and less frequent reloading that a drum magazine provides.