Of course machine guns are in common use. The number of them have been restricted since 1986. Personally I have shot 13 different machine guns.
Two times a year a big machine gun shoot is held in the Arizona desert. Without the restrictions, there would be a lot more machine guns in use. Machine gun is considered “small arms”. If machine guns existed at the time of the revolutionary war, the colonists would have used them. They possessed and used cannons.