I am not against all new things but in my opinion it would be hard to beat the old reliable 375 H&H. For the kind of game you are talking about hunting it would do very well. As far as accuracy goes the rifle would be the determing factor rather than the caliber. I just read an artical by Boddington where he reviewed the 375's. Several of them. He likes the added velocity of some of the newer rounds but admits that he could do just fine if limited to the H&H. I could not agree more. For anything the 375 H&H would not handle you would most likely be requred to use a caliber of 40 or more as some countries have a 40 caliber minimum. It would be worth his time to check out some of the countries he may hunt to see what the minimum caliber would be. I would look at the 416 Remington Magnum if he wants to go a little bigger yet. I owned one of those and shot a lot with another. Its a Game stopper yet the recoil while stiff if not terrible. The last thing I shot with mine was a rattle snake. An overkill for sure