Biggest difference between a military used M-16/M-4 and a civilian ARMALITE RIFLE (AR) is that the military rifle is select fire. Which means that you can choose between shooting 1 bullet per trigger pull or 3 rounds per trigger pull also called burst fire. The civilian rifle ONLY fires 1 bullet per trigger pull or semi- automatic(unless illegally modified) I realize their are military models that also fire full auto but they are rarely given to Ave. GI Joe.