Hmmmm,

when you throw antelope into the mix the complexity changes a bit,as few hunters can routinely shoot reliably around 350 to 400 yds and beyond.

While,I'm typically not a fan of the newer overbore magnums. I have one that until recently I would not have consider a favorite. It is a 300RUM custom with a kevlar stock and a recoil reduction unit in the butt,that groups several projectile weights from 140 to 250 remarkably well, almost all MOA with several Sub-MOA.

With the availability of solids, homogeneous copper and premium bonded bullets expanding in .308, accompanied by its flatter trajectory, high energy and light weight it is a consideration.

A major caveat could be ammunition availability as compared to "standard" calibres in the boonies.

We all know that all game animals have been taken with .270, .30-06 and .303, and one could make an argument for some classic favorites, 35 Whelen or 375 H&H, however, their more arcing trajectory increases the skill level needed on the longer shots.
The larger frontal diameters and the heavier bullets of these two latter choices may give an advantage on the closer heavier and/or more dangerous game.

On a sentimental level, I'd like to give my .256 Newton a go at the " one rifle" hunt for all the above mentioned game, when do we start?