Most of this discussion has been about domestic deer hunting. I would like to present a view of ballistic requirements for African plains game and dangerous game hunting.
Please keep in mind that a safari requires a flight halfway around the world for what frequently is a once in a lifetime hunt. $3-$5 per round is cheap insurance when the total safari cost is $8,000 to $50,000, depending upon game and the number of days spent on safari. I would also suggest that the following applies to guided Elk, Moose and Brown bear hunts in NA.
The basic recommendation I make to potential African hunters is to:
1. Use heavy for caliber bullets
2. Use premium, bonded bullets
3. Know the animals physiology
4. Practice, practice, practice. Then go out and practice some more.
As to plains game, you will do fine with your deer rifle. I first used Nosler partitions on safari with good results. Then bonded bullets arrived and I ran some experiments with my .300WM while on safari in Zambia with different brands of bullets. I settled on the Swift A-Frame. I would venture that this is now the most popular soft-point among African professional hunters, who have seen a larger variety of bullet performance on game than any other group in the world. Remington currently loads the A-Frame in its' premium safari line. I have used the A-Frame exclusively and with great success in .300WM 180gr, .375H&H 300gr, .416RM 400gr and .458Lott 500gr since 1999. Superior Ammunition will load the A-Frame in virtually any caliber for which Swift makes the bullet.
I have taken large, tough plains game with the .300WM - Zebra and Eland - as well as Leopard and Crocodile, using Swift A-frames in 180gr.
Bullet placement, is of course, the key to one shot kills, and this is why an understanding of the location of heart, lung and brain is critical. The most common complaint of African PHs is that clients cannot shoot well enough to make one shot kills. In Africa you pay for wounded animals and ethics and the law require a sincere effort to follow-up. In dangerous game, wounded animals will be tracked until found and finished or until further tracking is impossible. This can mean days of walking and tracking follow-up - days when you are not hunting other animals.
Practice can be accomplished with standard ammunition of the same grain weight. I shoot a minimum of 60 to 100 rounds in the months leading up to safari. Then fire up a box of the premium bonded ammunition you will be hunting with, to assure zero. You are now ready for the hunt.
As to dangerous game, here is how I load a rifle for specific animals:
Lion - All soft points
Leopard - All soft points
Crocodile - All softs
Cape Buffalo - 1st out a soft, followed by all solids
Elephant - All solids
Rhino - All solids
Hippo - All solids
How much ammo to take? Figure 20 rounds to check zero and adjust if necessary (things can get knocked out off zero on long air flights) and then 5 rounds per animal on license - 10 for Cape Buffalo. Only one load per rifle, ie do not mix weights and bullets within caliber. You are allowed 10 kilos (22 lbs) of ammo by the airlines. While this is well more than enough for plains game, you may come close to this on a 21 day dangerous game safari where both DG and PG will be hunted.
Keep in mind that airlines have reduced the maximum weight of luggage from 70 to 50 lbs on most carriers, with two pieces of checked baggage, one of which will be your firearms case.