I agree with DesertRam, when adding feral cattle and buffalo to the mix, I think I would appreciate the extra bullet weight that the 9.3x62 allows. I would be happy to take the 338 Federal after elk that rarely hit the thousand pound mark, but larger, tougher, and more unruly game would make me wish for a bit more bullet.
My own experience is with the 35 calibers; 35Rem, 358Win, 350RemMag and 35Whelen. The 35 calibers split the difference nicely, with the 338Fed/358Win and the 35Whelen/9.3x62 being very comparable to one another. With half ton game on the menu, I would choose the 9.3x62. Heavier bullets combined with a case length to get the greatest useful powder capacity would make it my choice.