I have 2 rifles in 280AI.
The first is a factory Remington 700 action 280 reamed to AI. I shoot 140 grain AB's with RL22. Shots 1/2 inch groups at 200 yards.
The 2nd is on a Remington 700 action with a 1-9 twist Benchmark barrel #5 contour 26 inches long.
It shoots any load I run thru it...