I will admit I'm not much of a shotgun guy, but I'm pretty familial with working on handguns and rifles and a 30 year tool and die maker so mechanical things don't bother me. I look up the owners manual and watched their video on disassembly so when the handle arrived I'm ready to go. My problem is the 12ga SAS that I have is NOT the 12ga SAS they show in their video or show in their manual. This one does NOT have the barrel retainer nut, the barrel is held on by the forearm nut due to a sleeve in the forearm that tightens against the barrel ring. This one does NOT have the gas valve assembly threaded onto the front of the barrel ring like the video and instructions show. There are NO threads in the barrel ring for it to screw into, but there is an O-ring inside the barrel ring.. Now I'm fairly certain that the kid took this thing apart and probably lost some parts, but I can't tell what. I would think there has to be some kind of piston that pushes against the sleeve that pushes the bolt rearward, but its not there. Another thing I can't figure out. I cannot get the bolt to lock rearward. According to everything I've seen it should lock back automatically, but it doesn't. I'm given everything a good going over and can seen nothing worn or missing that would cause this. The shotgun has very little use and suffers more from neglect and abuse than use. Can anyone shed some light on this for me please? I've emailed the company but have not heard back yet. I tried calling but no one was at home. I can't order parts by their website because I'm sure the parts don't match. Was there an older version of this shotgun that I'm looking at? Thanks guys.