The caliber of cartridge that modern light machine guns fire are usually less than medium machine guns. They are also usually lighter. However, a light machine gun can be noticed by the role it plays in a battle. Some machine guns, such as general-purpose machine guns, can be used as either a light machine gun or a medium machine gun. If it uses a bipod and fires in short bursts, it is a light machine gun. If it is used on a tripod and fires automatically for a long time, it is a medium machine gun.