I have one built on a MRC 1999 barrelled action, 1-12 twist. I have shot 3 different 225 grain bullets and one 250 grainer, and all have shot fine. I cant see myself shooting anything heavier than that. As far as powder, all I have run in mine is IMR 4350.

There is no way to coexist no matter how many bumper stickers there are on Subaru bumpers!