Hi David,
Mine is on a DPMS platform, my upper was way over gassed, and the adjustable gas block(one of the last things I did) was the part that really made it nice and reproducible as far as accuracy and precision. Other significant changes along the way swapped out the trigger from the standard lower kit for a 3 lb trigger. On the recoil system in the stock switched to a silent recoil system, and found a good brake to put on mine instead of a flash hider. Once I got it running right it is very close to my Bergara HMR as far as accuracy. I have not been able to shoot through the same hole yet at 100 yards with the AR10 need to reload for it. It was a fun project. The only real issue I still have with mine is an occasional small pin like dent in some of the brass.