Gotta love any AR with a 6mm bore. I gotta ask a question, if you don't mind. I have an AR chambered in 6x 45 or the 223 simply necked up to 6mm. It's a one hole shooter with several powders under the 70gr Speer bullet. I'm getting just a hair over 3100'ps out of it. The heavy weight barrel is a 1:8" twist. The question, why did you go to the 6mmAR rather than the much simpler 6x 45? I'm not totally familiar with your round so excuse the ignorance.