Sub Machine Gun A type of weapon. Real-steel SMGs usually have lower overall power behind each shot, but can fire shots more rapidly than assault rifles in fully automatic mode. They are designed to be used at close quarters and where high power levels are not desirable. Of course as airsoft guns are usually replicas, a real-steel SMG becomes an airsoft SMG, although rarely are the power-levels and rate of fire tuned in the same way as their real-steel counterparts.