NE members have used the 9.3x74R on cape buffalo.

I've used one on water buffalo, about 14 of them, but mostly cows and younger bulls. Have not doubt it would work on big bulls too, especially if one tried to avoid shots through major bones on the way in.

It may not be legal for cape buffalo everywhere.

Also it is a bit less than ideal IMO, but certainly can kill buffalo. It is not a "stopper" calibre on dangerous game, but also will stop them with good shots.

The 9.3x74R is an ideal calibre for medium game on battue or driven hunts, also for medium game brush hunts, and will stretch to game such as buffalo.

As for the .375, it has killed lots of buffalo and elephant in Africa. Don't worry about that!

Larger calibres are always better though if you have them, and/or can use them.