Porker is offering up a sound perspective. I would likely gravitate toward a 9.3x74R as a very versatile double in this situation. It's not a stopper, but it has lots of power on tap, and works very well on smaller big game as well as it does on the larger beasts such as moose, eland, zebra, etc......... It's not really street legal on DG, but that may not be an issue if one won't hunt DG.

Down under where massive water buffalo can be had, and is to be hunted, I'd want something larger than the 9.3 x74R, but how often would one hunt the big stuff? Although I have no first hand experience with scrub Bulls, water buffalo and the like, I'd think the 9.3x74R with appropriate hard premium bullets and expert shot placement would work in a pinch, but again, this medium bore is NOT a stopping rifle. Limited funds being what they are, if one can cover off 99% of one's shooting needs with a reasonably priced medium bore, that is what I'd certainly gravitate towards with its lighter recoil and broader application envelope. A seven pound short handy rifle is much more pleasant to carry around as well, also a consideration given that a hunting rifle is carried a great deal more than it is actually shot.