hodgdon goes to 96 grains of 50bmg on a 175-- a grain or two less on a 180 will be about top. My 7rum ran 95 of I 5010 on a 175 really well until the throat tired. 50bmg is basically the same powder but not mil-surp.Guys what are you using in your 7mm Ultramags with the 180 Bergers?
I have a Benchmark 9 twist, 29 inches long, Wyatt's extended mag installed.
My gunsmith recommended 50BMG.