AR-15 當然有軍用的版本，與民用的區別是裝彈量與自動化

For AR-15, M16, M4, Colt Model 6XX, XM-whatever, there is one major defining difference between a military AR and a civilian AR — select-fire capability. While all of these rifles have “safe” and “fire”, only military ARs have 3-round burst and/or full-auto.