As I've mentioned,, I've shot some Buffalo Bore ammo, and I'm also very familiar with them. Top end loads in general for sure.
I live in an area with an abundance of black bears. And here in NC we do have some really big ones. 500lbs+ are around. Yet,, even with all that,, I don't feel the need for BB ammo. I do cast my own,, powder coat them myself,, and use a 280 grn SWC design by MP molds. The load I use is very accurate,, and carries enough punch to put a big bear down if necessary. I have no doubts there.
Accuracy trumps power. You need to be accurate,, before the power can do anything. But you also need enough power to do the intended job.
Cowboy loads aren't the best choice,, but they too have a decades long history of use. Remember,, the 45 Colt was developed in the 1800's and used on all kinds of critters long before smokeless powder came along.
I tend to feel my .45 Colt is a good solid "comfortable companion" for most things. Trustworthy.