Before I jump in let me make a whole bunch of disclaimers:
(1) I've not been to Africa

(2) I've not hunted dangerous game unless Alaskan black and brown bear are taken into the equation

(3) I don't shoot, reload, etc for the 45/70

I think Mike hit upon something here about guys talking about how much of a killer the 45/70 when handloaded up is, and many of these guys never actually using them.

When I used to live in Alaska I used to get amazed by all the guys at the gunshop or the range talking about how the 45/70 in a Marlin lever gun was the "ultimate" brown bear stopper, or the "best gun for Alaska." That it could be loaded to levels "right up there with the 458!" What always struck me was that for the most part these were guys who actually never went hunting that much, or if they did never seemed to take that 45/70 with them. I just always wondered if it was so great why did you not see more guys in the field in Alaska carrying open sighted, hot loaded 45/70s to bag their moose and bears with.

I am not knocking on 45/70 fans here just sharing what I always thought was a strange observation with the rest of you.