The use of certain types of bullets IS a personal choice, but there are reasons that have nothing to do with choice for certain types depending on what type rifle you are using!
If, for instance, you are doing all your shooting with a bolt rifle, then just about any bullet recommended here would do the job if you do yours. However, if you are using a double rifle, then some types are not the best choice. With the choice of the bullet, the buffalo is not the only consideration to think about.
The Barnes solids are fine in single barreled rifles, but there are other solids that are better suited IMO. The solid that makes the difference is not what we think of as the traditional lead core solid, but the mono-metal solid. This includes the various so-called expanding solids that are mono-metal like the TSX, which has the bearing, surface that contacts the rifling being a solid mass of hard metal. The TSX with it’s pressure rings cut around the bearing surface is better than some of the earlier expanding solids like the X-bullet with a smooth bearing surface.
I must say here, however, that the pressure rings on the TSX are too wide, and are more likely to cause OSR (Over Stressed Rifling) than another type like the North Fork or the GS Custom, which have the pressure rings cut very thin, and the grooves between the rings deeper so the displaced metal of the pressure ring displaced by the rifling has someplace to go.
This is called a BORE RIDER type, and is far less detrimental to the barrel. As a rule the single barreled rifle that will be used for dangerous game will have far thicker walls than a double rifle, who’s walls are normally very thin. Top this off with the fact that the barrels are attached to the other barrel and the top and bottom ribs by solder, and the extra flex caused by a very hard bullet, my cause the separation of the barrels, or worse the permanent deformation of the barrel or barrels with OSR.
Most here will be using a bolt rifle, and in that case the solid bullet choice is easier, but if you are using a double rifle a little more though is recommended.
If I’m using a bolt rifle to hunt buffalo I place a North Fork soft point, Nosler partition, or Swift A-frame in the chamber followed by the same bullet as top cartridge in the magazine, followed with all solids down. In my double rifles I place a soft in the right barrel, and a solid in the left barrel. In all cases if I have a clear shot I place the first shot with a soft, followed by a quick soft in a bolt rifle, and followed by the solid in the left barrel in the double rifle. If I were hunting elephant I would opt for all solids, if hunting lion I would opt for all quality softs.
A buffalo will most times run a few steps forward at the first shot, then turn off , or swap ends and go straight away. In that case your not going to have time usually to get off more that one follow-up shot, and if it is quartering away, or straight away the solid has a better chance of getting into the vitals, and /or breaking large bones. If you have time for more than two shots, the rest of the magazine should be solids, and with the double the re-load should be all solids. If the buffalo charges then what ever is in the chamber needs to be utilized in short order, and here the old saying applies! “Once a cape buffalo puts together a concentrated charge, your options have been wonderfully simplified, you will kill him, or he will kill you!”
This also applies to lion, once he locks onto a target he will not be turned, and must be put out of service if you value your hide! Nothing short of a CNS hit will stop these two animals once they get going. A very hard slap in the face will often turn an elephant, but that counted on! SO what ever you load with the first shot is the telling action to finish the conflict, or start a fight. Ones the fight is on, the choice of bullets become a real factor.
So use you head when making this choice, and what ever you choose practice shooting the full magazine as fast, but as accurately as you can, at 25 yards, and count only the bullets that hit an 8 inch target. If using a double fire both barrels, and reload two more and fire those as well, and time all shots fired. You should get off four shots in about 5 seconds from a bolt rifle and four shot from a double rifle, with ejectors in about 4 seconds all on target.
Charges are rare with buffalo, unless wounded and being followed up. A charge from a wounded animal is far more likely with the cats, in Africa or brown bear in this country, than anything else in either place. However if it does happen, your pre-safari practice, and bullet choice will make the difference!