A gun built for sustained automatic fire. Machine guns are distinguished from assault rifles and battle rifles by size and ammunition capacity.
Machine guns are divided into three categories:
Light machine guns use intermediate-power cartridges, and are usually operated by one person.
Medium machine guns use full-power rifle cartridges and serve in both infantry and emplaced roles. Unlike light machine guns, these guns require a crew to operate, due to their bulk.
Heavy machine guns fire large-caliber cartridges-between 12 and 15 mm. Because of their size, they are typically restricted to stationary positions.
