To start with I wouldn't own a double in anything but a rimmed cartridge...thats the 11th commandment...

The 458 was and is a poorly designed cartridge, but never the less its a capable cartridge when properly hand loaded to 2000 FPS plus with a 500 gr. bullet and it will kill any animal on this earth with aplomb, I have seen it work, I have used it, and I know a ton of Africans that use it daily...Most load it to about 2100 FPS but 2000 FPS is sufficient though minimal for any DG......bottom line it works.