Just to keep the pot boiling: This info was lifted from Fr. Frogs Home Page
The following are taken from the regulations in place in Rhodesia.
Minimum requirements
Part A - Thick skinned, dangerous game [Buff, elephant, hippo] requires a 9.3mm bullet (.362") or greater diameter bullet with not less than 5.3
kilojoules (3,909 ft-lbs) muzzle energy; [Yes, I've noticed. Only a fool hunts buff with a ".375." Maybe they are trying to kill off the Yankee tourists
but at least they realize you need some kind of a "real" gun for the bad boys!]
Part B - Thin skinned, dangerous and heavy game [eland, giraffe, lion] requires not less than 7mm (.275") diameter bullet with not less than 4.3
KJ (3,172 ft-lbs) muzzle energy;
Part C - General big game [up to wildebeest and zebra, say 600-800 lbs] requires not less than 7mm (.275") bullet diameter with not less than 3.0
KJ (2,213 ft-lbs) muzzle energy;
Part D - Light big game requires a bullet at least 5.6 mm (.220") and 850 Joules (627 ft-lbs) muzzle energy.