Joseph's right. I've not hunted Africa yet..but I would practice shooting out of a blind, and just use anything as big or bigger than a big mule deer for a target and shoot it straight up above where the front leg crosses the body, as their vitals are more forward than our game.
There is a book called THE PERFECT SHOT, comes in paperback, would be a good investment to see where the heart/lungs are on most of the game you would encounter in Africa.