06; I prefer Rem 9 1/2M primers for any magnum except with 100+ gr loads of H-5010, H-50 bmg, etc, and I am about to try them on H-5010. They give consistant low s/d's and the cups are soft enough to give pressure warning before you start seeing bright spots on the back of your cases.
Check out the thread on .300 Win Mag powders on this forum.
My opinion, Tom
Texas State Rifle Association Life Member
NRA Endowment Life Member
A big fast bullet will beat a little fast bullet every time