I was thinking about a .300 Win Mag, till I shot one. OUCH! So .30-06 is about the upper range of what I can shoot comfortably, and that's more then enough power for me. Plus, I'm planning on getting a M1 Garand, so same dies to reload with. But I can put more powerful 'hotter' loads in this because I don't have to worry about a gas system.
I always made one prayer to God, a very short one: "O Lord, make our enemies quite ridiculous!"
He granted it.