Without using it, completely armchair, I would say a .500 NE, .500 Jeffery and .505 Gibbs would be the perfect close in buffalo choices.

If longer distance of shooting in a herd can't see why a .375, .404, .416 won't work.

Carry both! Scope sighted smaller DG rifle and dr .500.

I don't see the purpose of ultra high velocity DG cartridges, when a larger calibre works better than more fps. Everyone to their own.

In the meantime, my .450 No.2 NE will be fine as my preferred choice. Would love to give the .404 a go soon, even though it IS a modern bolt action. My .375 ba and 9.3 dr are also fine.

Actually I want to really give the 10-bore WR DR the next to.

The word "perfect" is an extremely subjective word. And guaranteed to create debate.

PS I wonder if I replied previously and how close or different this response is?