Your best bet is to buy a variety of bullets and see what your gun likes. The most consistently accurate bullets I've used in my three .454s have been 240 gr and 300 gr XTP Mags. I have not taken anything with the 240s yet but the 300 gr XTP Mags have performed very well on deer. 300 gr Sierras have also been accurate in all three guns but in my experience they are harder and perform like a hardcast bullet on game.