I don't have a .458 Win Mag, but one of the original cartridges it was designed to emulate, the .450 No. 2 Nitro Express. It fires a 480 gr FMJ at 2,170 fps. And I don't feel any lack of confidence when facing an elephant or buffalo with it.

Even given the fun of my last water buffalo hunt. With elephant you shoot them very close, and so far ... no hubris intended ... have a 2 out of 2 success rate on first shot brain shots. That gives confidence ... now when a buffalo charges, I need to let it get a lot closer before whamming it ... and shooting it properly in the right place rather than hoping ... for those that read the story, first time I had trouble, otherwise no problems for the other dozen plus ...