A light machine gun or LMG is a machine gun designed to be carried and fired by an individual soldier, with or without an assistant, and used in a front-line infantry support role. LMGs are often used as squad automatic weapons.A light machine gun may be identified either by the weapon or by its tactical role. It is used to fire in short bursts, usually from a bipod: a sustained-fire mount such as a tripod is a characteristic of a medium machine gun. Some machine guns - notably General purpose machine guns - may be deployed as either a light machine gun or a medium machine gun. As a general rule, if a machine gun is deployed with a bipod it is a light machine gun; if deployed on a tripod it is a medium machine gun - unless it has a caliber of about 10mm or larger, making it a heavy machine gun. Modern light machine guns often fire smaller-caliber cartridges than medium machine guns, and are usually lighter and more compact.