Re: 22-250 AI and 75 amax
I had a hard time getting my .22-250 (1-14" twist) to shoot the 52gn A-Max's. I was perplexed because this rifle shot the 52gn Sierra MK into .2's. I tried every powder I had that I thought was within the speed range needed for the rifle/bullet combo. I know I tried IMR3031/4320/4895, Varget/H414/H4895/BL-C(2) and Alliant's 10X & RL15. The best I got was about 1/2" for 3 shots at 100yds. I actually shot a couple of boxes of those A-Max's trying to find a decent shooter.
Then I ran across some VihtaVuori N133. (I bought that because I had a .223 at the time with a 1-9" twist) I tried the last few A-Max's with this powder and CCI BR2's in my .22-250. The first group (31.5gn) ran .2795". Subsequent groups were 32.0gn = .8705", 32.5gn = .6100" and 33.0gn = .7670". Velocities were 3692, 3733, 3807 and 3831fps. Too bad I was out of them as I vowed myself I wouldn't spend anymore of my money on those darn Hornady bullets - in any caliber!
I've since gotten rid of the .22-250 and .223, but I still have the N133. Good luck with those A-Max's! JohnnyK.