You made mention of the 375 H&H and the 416 Rigby... what else? I know what makes a buffalo cartridge; that is not my motivation. I am curious how preferences or availability would compare with some of the African countries.
Do the 375 or 416 Ruger cartridges have any following? Do folks subscribe to the frontal mass of the 458 Win or the Lott? Are there folks that tote my favorites 9.3x62 or the 404 Jeffery?
The .375 H&H has by far the biggest following here in Australia for Buffalo.
I have seen a couple all the calibers you mentioned used but they are definitely not common over here. Other than for collector's or some just like to try something different.