As I've stated elsewhere, too many American hunters are overgunned when they go after Africa's antelope. They've heard that African game is tougher than American elk, moose and bears (Baloney!) and they buy a new shoulder thumper for their first safari.
They'd be better served if they took their favorite deer rifle if it's at least .270 in caliber.
Bullet placement is everything, and unless a hunter can handle the recoil of rifles that kick more than a .300 Winchester Magnum (my personal limit), he cannot shoot as accurately as he can with a rifle with mild recoil.
Bill Quimby
I would like to chip in and add my 2 cents here. Bill is absolutely right in the fact that most American hunters come to africa overgunned, but be under no illusions regarding the toughness of African game. Saying it is not tougher than north American game of comparitive size is a falacy refuted by most suitably experienced hunters(especially ones that have learn't the hard way). I've seen an impala run 300 meters with a lung shot that broke both shoulders from a 308 at 60 meters and a warthog that was hit twice with a 308 from 100 meters, both perfect lung shots and we found it a couple hundreds meters away after picking up a handful of flesh on the other side of where it was standing when it was hit(no joke!). My first impala was botched befond belief, I broke both front legs as the bullet passed through the sternum below the heart, it ran for a long way before a follow u shot dropped it. I may not have hunted the US but, I was doing some research on ballistics for a new antelope rifle, I ended up watching videos of some hunting in the US, one video in particular stood out. A guy took a shot at 700yds with a 243 at a whitetail and the bullet hit low, breaking the left front leg and sternum and it was almost as if it were a heart shot. It dropped on the spot and didnt so much as twitch after 30 seconds(how it happened, I cant fathom). Disregarding this as a fluke, I also saw numerous other videos showing north American game going down easily(comparitively). This is just the way it seems to be.
Having said that, shot placement is everything! Nothing less than a heart shot will be certain of a quick kill and not an animal lost to die in a thicket 15minutes later on African game(as a side note, buffalo have been known to run 250 meters after a perfect heart shot, and I'm sure they are not the only animals that can). Your 270 will be perfect for body shots up to nyala with a Barnes X or similar, just make sure of your shot! A 300 win mag makes mincemeat of anything but unless the shot is on the money, that trophy bushbuck will only die 3 hours later if you hit it in the guts. While a 22 hornet, with a 45gr head with drop a kudu(not that I recommend it, its just something I've seen done, as well as doing the same on countless reedbuck myself during culls without wounding even one) on the spot if you place your bullet behind the ear so that it will exit the eye at a sensible range. No animal has ever walked away from a heart or brain shot, regardless of the calibre used(.22lr on elephant has been done, with one shot to the heart, documented by Kenyan park rangers who forced a poacher to prove his claim after being caught with ivory and a .22lr who was adamant the .22lr got him the ivory, definately not an acceptable use of a .22 though, whether it can do the job or not!).
Make sure you can shoot and will not negate that time on the range by getting "bok koors"(buck fever) as there is no greater cause of wounded animals in my experience bar none. A foreign hunter once came over here to shoot his dream trophy Reedbuck. On the range on the back end on our farm, he demonstrated an ability to shoot half MOA groups on the range and ended up shooting a yearling, 1 meter to the left,(40MOA off target) in the rump from a Reedbuck(that would have qualified easily for Roland Ward) he was aiming at. We were so shocked, we put up a target immediately and re-checked the rifles zero, it was dead on! This is an extreme case and I've heard nothing even close to rivalling this eye opening experience but its an example of what can happen!
What I'm trying to say is don't compensate for a poor shot with a big calibre, it will not make it any better other than maybe shorten the time it takes to die much later that afternoon. Make sure you can hunt(much more than driving tacks), dont take chance shots because its your last day and you aren't likely to see another trophy of that species, and you'll be fine. For this reason, for heart shots alone, I vote for 243/270 for anything up to a reedbuck, a 308 for anything up to Kudu at close range. And a 300 win mag for eland and similar. If you're experienced enough to take head shots consistantly out to 150 meters, you shouldnt be taking advice on this topic in a forum because you already know what your bullet can do and what you can do with it.
As I was always told, "All the muzzle energy, bullet weight and penetration in the world means nothing unless its emparting that energy in the right place and making a hole in the right organs.
Cheers
