It is becoming more and more popular, reason being it is 375 and therefore legal for DG in all African countries. The 9.3 x 74R, is a fine round too, but it just isn't 375 and some official may pick that up and ruin your hunt. i wish I could upload a video on here, would show you how mild the recoil is for 2nd shot take up.
Kevin, with a modern load, what is the actual velocity at the muzzle on your gun?
While I remain skeptical this is a good idea for Buffalo, I think it is a heck of a lion/leopard/eland/kudu setup you have there.