For water buffalo, scrub bulls, banteng and cape buffalo, I have used my .450 NE double, my 9.3x74R double and my .375 H&H bolt action. 480 grs, 287 grs and 300 grs respectively. About twenty beasts between them all, not a lot by some standards, biut still enough to make a showing.

All of the above work. I know from personal experience with the last water buff, there can be times when even a .450 NE does make a bloody buff flinch, when he is coming for you ... Usually they work well enough, a small amount of times the circumstances mean the bigger the better. A reason I was told by one Territorian on NE, why he no longer uses his 6.5mm Mannlicher for just that reason ...

The .404, the .416s are in the middle of the above range. No reason why they won't work well, in the right bullet in the right places. Probably the best calibre choice for bovines using a bolt action, and not in very close bush or jungle.