Let's talk about cartridges for plains game hunting. Again, you can only bring two rifles. And maximum three and that's really too many. So you can't be too specialized.
We could theorize that something like a .22 centerfire would be ideal for the smaller African antelope. But really, too specialized and you can't bring enough rifles. So, the lightest rifle you should probably think about is something like a .243. That and the .25-06 are very, very popular with local South African hunters.
But again, those are, again, specialized rifles. You're not going to be able to use them on a wide range of game. So, if you bring a very light rifle as the lighter of your two rifles, then your second rifle needs to be even more versatile.
For most of us, for minimum choices, you need to step up a little bit. You know what? Most of our really popular American hunting cartridges are also popular in Africa as well. A good sound minimum for the general range of African plains game would be the good old .270 Winchester. You could make the same argument for 6.5mm and all of the 7mm. But somewhere in there, the good old favorite American deer cartridge is going to be just fine for most African plains game, up to certainly kudu and perhaps up to zebra as well.
For all-around excellence, the most versatile choices are probably America's favorite, the .30 caliber. I'll be honest. I don't think there's a better cartridge out there for African plains game than our good old .30-06. It'll take almost the full range. However, if you're hunting in more open country and you don't mind a little bit more recoil, then one of the .300 magnums is perfectly suitable. And also, they're favorites of mine.
So, what am I saying? Well, I'm saying that if you have a .270, you've already got a rifle that's suitable for the majority of African plains game. If you have a .30-06, you've got one of the best African rifles going for almost all African plains game. And really, the only exception to that is the eland.
Now, larger cartridges are obviously more quickly effective on the very large plains game. But the only African antelope that really needs anything larger than a .30 caliber is probably the eland. So, the upper limits of your African battery really depend on what you intend to hunt.
If you plan on hunting an eland, then maybe you do need a larger cartridge. A .338 is a great cartridge for eland. Standard choice in Africa is a .375. But there's really relatively few African antelope that need cartridges quite that large and powerful.