I started loading for the 45-70 in 1975 when I bought my very first Ruger No. 1. It is on my short-list of all-time favorites!
I have a near virgin Henry in this fine caliber that needs to get some of the shine knocked off it! So far I've only loaded 300gr JHP and 350gr cast for it.
Last week added a Skinner peep. Sweet little rifle!
Glad to see the 45-70 getting some much deserved love here on AH.
Also on Beartooth - a guy used the Piledriver for a straight through-and-through at the shoulder on a 2200 lb American Bison out of a Sharp's replica, I believe (total penetration was just shy of 36" as I recall). Not sure why they have such a bad rap in Africa other than it's-just-one-of-those-things-that-isn't-done. American bison were killed in the tens of thousands with old trap-doors and their low velocities/pressures. No reason to believe that cape buffalo are any less prone to dropping in the same way.
I wouldn't try to shoot a cape from beyond 100-120 yards with one, but I wouldn't go a lot further than that with a 375 or 416, either. I haven't been over there (yet), but in the brush country, there don't seem to be a great many opportunities to go beyond 100 yards anyway no matter what's at the business end of your rifle.