Light machine gun

Light Machine Guns (or LMG) are a class of small arms that are either adaptations of an assault rifle (generally with a larger magazine, a longer barrel, reinforced receivers, etc.), or a weapon design in its own right, chambered for an intermediate rifle (assault rifle) cartridge. Light machine guns are man-portable, and may need one or two operators. They can either be magazine-fed or belt-fed, or have the capability for both. Light machine guns usually fire from an open bolt, as this prevents rounds from cooking off due to overheating; however, there are a few exceptions to this rule, the RPK being one of them.

Most weapon designs also have the ability to quickly swap out the barrel, should it become overheated or a malfunction occurs that leaves the barrel damaged.

Roles

Light machine guns are used to provide suppressing fire, usually being fired from a bipod. As a result of this, their effective range is generally greater than an assault rifle firing the same type of cartridge; hit probability is greater on an area target than aimed fire from a comparable service rifle.

Some light machine guns (namely, the M249) are pressed into the automatic rifle role; while they can serve this role, they are not optimal for use here.