Range would depend on game. I have no experience shooting African game so take this with as much salt as required in your circumstances.

For me here in BC. a .40 cal. 300gr. decently shaped projectile TXSX type driven at those speeds would be an easy 300 yard moose or elk bullet - good iron sights or low powered scope, no change. Even my M96 9.3x57 is just such a gun using 286's through 300's.

It's an accurcy game and must be decided by you, during your practising. The gun has the power - you supply the accuracy and limit range to yours and the situation's accuracy possibilities.

I've heard African game is tougher, so be it.