The AR15 style, Generation 3 AR12 semi-automatic shotgun is the most updated version of this shotgun. But the manual doesn't really explain how to disassemble the gun very well.
Well, since the manual isn't very instructional and since there have been some slight modifications since Generation 1. I made this video to help the Generation 3 owners learn how to best disassemble and reassemble it and included some helpful information on replacing the O-ring and making your gun operate more smoothly.
Enjoy.