RE: Recoil of .458 mag.
I've shot one with a light load and cast lead bullets before. It kicked less than my .308 but was much louder. I think the recoil of a full load in a heavy bolt action rifle shouldn't be too bad to shoot if you limit yourself to a few shots per outing and wore a recoil pad. The 450 marlins in the lightweight guide gun are a whole different story though.