I hunted 4 buffalo already, I shot and kill them all with a 375HH, I believe this is an outstanding caliber and all round... however I think is not enough for those beast.
I shot one of them 12meters away from us, the first shot straight into the lungs hitting the hart and the second shot straight into the chest hitting the hart again... and the buffalo did not stop... he run 80-90meters and hide into a thick bush, hitting it looking for someone to fight... the area was burn down we could see it and managed shot it 4 more time. Since then I believe 375HH is just not enough!!!
I don't think it was the caliber, the 375 H&H is fantastic, watched several of Mark Sullivan's videos and they have put several round from the 375 to 600 NE into a Buff,and the SOB just keep's coming. Don't give up on the 375.
I do not think is a problem of caliber... it is just a problem of self confidence....
The 375HH is an outstanding rifle... however since then I prefer facing one of this buffalo with something bigger.
I the coming month I will have my new 470NE ready to fight!