A friend here in Australia is a professional roo shooter who also culls feral goats, donkeys, camel, wild dogs and, for a significant period, culled Asiatic water buffalo in the Northern Territory.
He has used 303 FMJ loads, a 375 H&H and a 416 Rigby for buffs but his gun of choice is the 45-70.
The combination of a big hole, a fast cycling action(1895 Marlin) and a heavy hit made it his preference.
Further, he never worried about shoulder shots to preserve the skin for a mount.
All of his safest shots were neck shots and the old 45-70 completely blitzed them.
He also enjoys messing around with cast loads.
Suffice to say, 45-70, with correct bullet placement and correct bullet choice, is up to almost all game.