AA2230 is definitely the powder for the .458 in my opinion and experience. I like 72 grains with a 450 grain North Fork solid or TSX (depends on application) bullet. 2250 fps in a 22" barrel. You don't need more. I killed an elephant and a buffalo with that load.
Caution: It was safe in my rifle but maybe not in yours. Work up slowly.
I don't understand why the factory ballistics are so lame.
