Machine Guns refers to fully automatic guns. However, this doesn't include assault rifles due to the fact assault rifles are from a different family. Machine Guns are usually used to fire hundreds, or even thousands or a lot of bullets in some seconds. Machine Guns usually have high ammo capacity, ranging from a normal 50 or until a whopping 300. Another type of machine gun is the Sub Machine Gun. SMGs however, are designed to fire pistol rounds.