Speaking about performances, your caliber is pretty close of my .338 Lapua magnum and I have killed most of plains game, from duiker up to giraffes, with it. For sure, it is a bit overkill for smaller animals but it will do the trick.
I met a Namibian PH in the past who loved RUM calibers and he had both .300 and .338, but I didn't see them in action. He gave me one cartridge of each for my collection.
For dangerous game, I would say lion and leopard won't be a problem, same thing for crocodile.
In Namibia technically, there is just a minimum energy required to hunt dangerous game and this minimum is 5400 Joules. I don't how fast your A-Fram's go out of the barrel, but I'm sure you are well above this minimum. However, I don't know if there is a PH who will allow you to shoot a buffalo with this set up ? They will probably prefer a caliber with a larger diameter and a heavier bullet !
