A firearm designed 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:
Medium and general-purpose machine gun: Fire full-power rifle cartridges and serve in both infantry and emplaced roles. It typically require a crew to operate, due to their bulk.
Heavy machine gun: Fires large-caliber cartridges (at least 12 mm but less than 20 mm), dedicated for anti-materiel role. Because of their weight and large size, HMGs are typically restricted to stationary positions.
