I'd go with the rock river. I had a 20" bull stainless upper on an armalite lower and ended up selling it to a friend while shooting at a range. He's a blaster and has never seen tight groups. I didn't have any hand loads for it, but he had some federal ar varmint ammo or something like that. I shot some threw it of a bipod and 24x scope,and Damn it punched out a tinny little hole, 1/4 -5/16, for 5 shots, I wanted to stop at 4 lol! I was waiting on wind conditions and took prob 10 mins to shoot the group. When he seen it he said he had to have it and offered me a crazy price, so it went home with him. My RRA was a good one.