Presuming you would be talking about using a double rifle in this caliber? The original regulation will likely dictate what load you will be able to use, below would probably be close in an original BPE double.

The .577/.500 No2 BPE was typically loaded either:
130grains black and 340grain copper tube bullet at ~1850’/sec
130grains black and 380drain solid lead bullet at ~1775’/sec

The later Nitro for Black was:
53grains Cordite and 440metal base (similar to a gas check) solid or copper tube lead bullet at 1675’/sec
That NfB load ginned up ~2743 ft.lb.

The .577/.500 No2 was said to be fairly popular in India for Tiger and other soft skin game.

The larger .577/.500 Magnum 3 1/8” BPE managed considerably better performance for the day.
164grains black......440 to 480grain bullets at ~1800+ FPS

Your mileage may vary.....
- Mike