You know those guys that say buffalo turn bullet-proof after the first shot? They're the ones with a magazine full of solids.
I once had to shoot a small mule deer 3 times with a .7mm Weatheby Magnum. The bullets (Nosler partitions) did not hit a bone or open up. This is a bullet that I had used on dozens of mule deer (and elk and black bear for that matter) with mostly spectacular results.
The rationale for solids as backup shots on buffalo is that they can penetrate through 5 feet of buffalo and still break bone, putting you ahead of the game. Hit a running buffalo with a raking shot on the left side and you will encounter a thick paunch filled with partially digested grass. You need all of the penetration you can get.
My advice is to listen to your PH. He has probably seen more buffalo killed than any stateside hunter, regardless of how many trips he/she has made to Africa.
JMO
BH63
