morning, I have custom built 22-250AI. same twist, 28"
hart barrel Rem. 722 action, timmey comp trigger,
anymore features. 4320, RL15, W760, 4064, 4831sc
I use the burn chart to help group the powders that
have the have close burn rates. Bullets, barnes
berger, TMK's with the heavier weight bullets.
I tried H4350, H414, and IMR7828ssc with 75gr Amaxes in my 8” twist 22-250. Velocity was good but accuracy was lacking. Then I tried R15. Consistently bug holes with groups in the .3 -.4” range and gives me just short of 3300 fps. It’s the proverbial lightning bolt and easily the most fun combo I have.