If you don't reload, then as most have mentioned your options are more limited. Not sure you can get the Federal TBBC, but it is a well designed bullet which Northfork, Rhino, and others closely duplicated. Swift A-frame in either their factory loading (fastest 300 grain loading I have chronographed and accurate in my rifles), Federal’s factory, or Norma’s (if they still load it). And of course Barnes TSX which most likely will give you the deepest penetration (loaded by Barnes and Federal of which Barnes is the fastest Ive found and most accurate in my rifles).
I personally would pick which ever shot the best in my rifle and go with that.
To clarify, I have only taken 1 buffalo to date and it was using the Barnes. But I have shot all the others and researched a great deal. I believe any of these will get the job done if you do your part.
Take a look at the bullet performance thread on AH. It might help you.
Enjoy your search and your exciting hunt!