I have a CMMG conversion in my Delton, but have always used CMMG magazines which require no adapter. I'd look at the following things to see if I could figure out what is the problem. Is the adapter staying securely in place? Any shifting would cause problems Have the magazines been proven to work fine in a different rifle and are the broken in well? Is there any evidences of the bolt dragging on the adapter or top of the magazines? If it is dragging it could cause some of the problem. The light strike FTF shouldn't go with a magazine adapter problem unless the bolt is dragging on the adapter. I'm just thinking out loud as to what I'd look for in the trouble shooting.
America is way behind on the utility and sense of suppressors. Although more and more states are allowing hunting with suppressors, you still have to buy your suppressor, give the dealer the $200 for the tax stamp and wait six months for it all to clear.
Did you have to jump through extra legal hoops to get the 12 inch barrel and suppressor? Here it would cost you at least one if not two $200 tax stamps.
I think the Ruger stock would look fine and it certainly would be an attention getter at the range. As a thought have your friend who air brushes do something with the Ruger stock.