I honestly love my Ruger M77 with a bull barrel 26 inches long...it shoots 1" inch groups. Great small antelope gun!
The .243 is a perfect fit for certain game/hunting scenarios.
However, I am too lazy to bring a specialized, extra rifle/caliber to Africa for only a narrow corridor of animals in size.
Some folks like it for impala and I will not try to argue it is too light for them but, I will in fact that it is too light for them when I am the paying client.
So far, the lightest rifle I have used in Africa has been the .30-06 and 220 grain RNSP which is a bit much for some, including impala but my vote is that it is not very much too much, so to speak (if I was a rich as Barry Obama, I'd have a SxS .303 for hunting small antelopes in the thick foliage).
Of the very few pygmy antelope species I have shot, it always happened while just hunting whatever size PG species we could find and hopefully outsmart, not necessarily setting out just to hunt the little ones.
This has resulted in myself being able to promise you here that, a .375 diameter JSP bullet, weighing 300 grains and leaving the muzzle at 2400 fps does very very little meat and skin damage to the tiny ones.
Some folks use a "solid" for this but I have never been that organized so, I have just shot them with the same heavy soft that I used on the larger antelopes as well.
If I lived where there were large herds of America pronghorn or African springbok, I might consider owning a .243 again (best .243 I used to have was a Pre-64 Model 70 in .243).
However, something like the 6.5x55 or 7x57 or 7x64 or my personal favorite long range caliber - the .300 H&H - would be more to my taste for such as pronghorn or springbok hunting.