From the one side, there's a group that says that the .458 Win Mag isn't really enough for cape buffalo, etc.
It isn't. Capstick wrote of a hunter emptying his .460 into one. I believe he was on his second mag when the bull went down.
From the other side, there's a group that says the hot-loaded .45-70 will easily take cape buff's.
It will. Capstick wrote of a lady- a fantastic marksman- who took one with a 7x57mm- with one shot.
with the right loads, a .45-70 will break both shoulders on a cape buff or shoot all the way through one LENGTHWISE.
I hope this has been explained to satisfaction. I remember seeing a picture of J.D. Jones with a buff he had taken with a .45-70 from a Contender years ago. JD called the .45-70 "the best 100 yard sledgehammer".
Randy gets a lot of respect from me. I believe he knows what he's talking about. I hope you can tell from the two examples given, that the HUNTER is the big variable.