Gibbs you said
Taking these things into account, there are very nice .308 rifles out there in the AR platform that do exceptionally well with 1:10 twist and 4 or 6 groove rifling. They are, after all, somewhat designed for battle rifle conditions and as such if you look for extreme accuracy, you are better at looking at bolt action .308 over the gas operated semi autos like the AR series.
The barrel I have is not really bad at all. I have been able to get a group at 100 yard of 0.366" using 150 gr Hornady SP bullets non BT with molly coating. I just think it would be (my opinion) a nicer shooting rifle and a bit easier on brass for reloading if I had a mid length gas system barrel on it
outstanding grouping at 100 ! you answered your own question though...outstanding accuracy equals bolt action.....So why dont you try a rainier arms ultramatch grade barrel for your ar platform?.....they come in a middy and they are 6 groove and guaranteed to shoot sub moa....these are not bhw made barrels
so you are plus one on the groove... not to worry :) Wash