 They're very similar. The biggest difference is that the M16, the military's rifle, is capable of automatic fire, which means if you pull and hold down the trigger, it'll keep firing bullets. Whereas the AR-15, anyone can pretty much buy in a store, is one trigger pull, one bullet. It goes as quick as you can pull it, but that's still the main difference. But the gun itself is functionally otherwise the same as what is being used by the military.