I don't know about other guys .458's, but mine puts 350gr. "X" bullets, traveling at 2,350/2,400fps, 3" high at 100 meters, with 500gr.softs and solids making 2,200fps while striking 1-1/2" high, same aiming point.
: This gives .470 Nitro-type ballistics with the 500's, while the 350's are only down 10" or 12" at 300 long yards.
: I suspect you'd never shoot past 200 or perhaps 250 yards on plains game and the 350 "X" would handle that quite well.
: With the appropriate modern bullet, one should be able to make the big bore do all the work necessay.
: On the other hand (one generally has two, a 9.3x62mm, or 64mm appropriately loaded would be a better plains-game cartridge and will still suffice with good bullets and shot placement on buffalo. I cannot stress the importance of proper shot placement and the 9.3's (or a .375) make that easier (for most of us) than any of the larger bores.
: Although my actual game experience doesn't go to Africa, the above makes sense to me. The large mediums worked 100 years ago, and should be even more effective today with the wonderful bullets available.