Benbo,
In my experience Trophy Bondeds are less likely to exit than the 350-grain TSX you planned to use, but more likely to exit than A-Frames, which tend to expand wider.
On a slightly different subject, the very first bullet I used on buffalo was the 300-grain Fail Safe, from a .375 H&H. I hunted in the Okavango Delta of Botswana, and the bull was as big-bodied as any I've seen killed (the bull my hunting partner got was just as large, if not a little larger) and the FS exited on a broadside shot that landed just behind the shoulder, leaving an exit hole the size of my fist.
I intended to put it in the shoulder, but there were two bulls at the end of a herd of about 200, heading down to a river in the evening. They were the biggest bulls in the herd, but one was slightly bigger. They were moseying along together, sometimes side-by-side, The PH whispered to NOT shoot unless they stopped--and to make sure the other bull was clear.
They stopped about 60-75 yards in front of us, with the smaller bull behind the larger one. Then the bull on the far side started walking again, and I aimed at the big bull's shoulder--but apparently he couldn't tolerate not being with his buddy: Just as the .375 went off I could see him also start forward, and the bullet landed maybe 4-6 inches behind where I'd aimed..
A lot also depends on the size of the buffalo. They can vary considerably depending on the region. The buffalo some friends and I hunted in Tanzania's Selous Game Reserve were noticeably smaller-bodied than Okavango bulls.
