Whenever the topic of scopes for DGR rifles comes up, people tend to fixate on the slim chance of a charge, or that buffalo and elephant are big and don't need a lot of magnifying to see. That's true enough, at typical buffalo hunting distances you don't need any scope, and probably don't even need irons to land a killing hit. Trouble is, the problem is not smacking a highly visible large target at close range, it's getting the bullet through the dense bush that caused the range to be short in the first place. There's also the problem of identifying which end of that obscured black blob has a head on it, and which of the many black blobs is the one you're supposed to be shooting at. It's nice if the vitals you find are connected to the head you want as well. Then you try to find an opening that will let you thread your bullet through to your animal before they all move or spook and you get to start all over again. Since the target is the opening you find, a bit of magnification that can be accessed at will not go amiss. It's much easier to miss all those little sticks if you can see them.
I've got a 2.5-8 on my .458 Lott (used to be a Win Mag) and far more Buffalo got shot at 8 power than ever met their demise at 2.5.