For standard everyday use by ordinary citizens for taking Cape Buffalo (not doing "stunt" work), I have some serious doubts about promoting (directly or indirectly) the use of 45-70's for such a potentially life altering task.
Mr. Pearse's professional hunter also had these doubts - before he witnessed what the load Pearce was shooting in his .45/70 could do! He had previously seen how come of the 300-grain .45/70 softpoint ammo worked -
NOT!!-, and had to be convinced that Pearse's ammo made the .45/70 an different propopsition entirely!
It is the bulet, correctly designed for the job at hand and propelled at an effective velocity level, that determines if a given rifle/cartridge combination is going to perform acceptably on any particular type of game animal,
AND NOT THE SIZE, SHAPE, OR AMOUNT OF POWDERcontained in the case!!