micmacman, yes it's difficult to build a completely accurate M16A1. I built mine a long time ago when NoDak Spud was the only game in town for retro lowers. Fortunately, I grabbed a couple of the short lived Sportsman's Guide's M16A1 parts kits while they were available and built myself a very good replica of the rifle, no fun button, of course. I take it out now and then to Carbine matches at my club which brings a laugh from everyone since I usually bring one of my custom built full-race AR's.