Gerg, sorry for the delay, was out duck hunting this afternoon. BR had the correct answer. The original design was actually a liability because it was three prongs sticking out of the end of the barrel and when you were going through the jungle in Vietnam or quickly moving your M16 in a fire fight, the prongs would catch on branches and vines and hang your gun up. So they redesigned it by extending it with a ring of steel around the end with porting on the side. That way nothing could hang up at the end of the barrel. I don't know what they look like now. By the way "porting" a barrel of a rifle or shotgun by basically drilling holes in the side of the barrel at the end to let gas escape to reduce recoil is similar to a flash suppresor but not outlawed.