Hi again piratensafaris,
Get yourself a .30-06 and shoot 180 grain or heavier bullets.
It is not very exotic but regarding it’s performance on 99% of the world’s hoofed animals, you will be very happy with same.
Personally, I like 220 grain round nose soft points in the .30-06.
But again, most bullets from 180 gr upwards, tend to work quite well in this cartridge for Africa, yes quite.
If however you cannot abide the excellent but boring old .30-06 and simply must have something a bit off the beaten path, take a look at both the .338-06 and the .35 Whelen.
Both of those are wonderful African cartridges, when loaded with bullets beginning around 225 gr, up through 250 gr (or even heavier if you hand load).
A couple more wonderful Africa worthy hunting cartridges are the 8x57 Mauser, with 196 gr bullets and the 9.3x62 Mauser, with 250 - 286 gr bullets.
Screeching ultra high velocity in Africa is generally not the best performer as, just like 375Fox has already mentioned, most (most) African game is taken at relatively short range and often foliage is present, between the hunter and the critter.
That said, indeed if you insist on bringing an ultra fast caliber to Africa, I recommend you load it with and ultra tough bullet, such as the Swift A-Frame.
Parting Shot as it were:
Since you are planning to include hunting in Africa as part of your life, sooner or later you will want a .375 caliber rifle.
May as well start looking now, so that you can have a great understanding of what the various makers have to offer, and what they should cost, well before you run across one for sale.
Cheers,
Velo Dog.