Aussie, far be it from me to pass judgment on where other's draw lines. There are more than a few animals I'd never shoot. That's a personal thing and needs no explanation.
To me a buffalo "hunt" is really a "meat shoot" which is why they should be head shot. Saves meat and puts them down dead asap just like a cow. My Grandad had a slaughter house and as a kid, before it was made illegal, we'd use a Sears single shot 22 to put down cows for slaughter. I see Bison exactly as I see cows and definitely don't see them as a game animal per se.
I never heard of that law, is it just in Montana? We still have a cold storage in our family. I worked there for several years, and many more hunting seasons, and they still use .22lrs to slaughter cattle, sheep, and hogs. I did used to break out a .22mag once in a while when I dropped a bison -- I'm not sure if I had to, but I just did. It makes it easier for the taxidermist that way. From 10' to 30' right between the eyes and a few inches up I never saw one that didn't die instantly.
My dad also used to raise buffalo years ago (well Bison Pete who I mentioned earlier in this thread did, but on our land). We'd feed the retired bulls then drive back along them while they ate and let the "hunter" drop one from 50 yards or less. They got to bring their own rifles, but my dad was always laying across the hood with an 06 trained on their head just in case. IIRC I don't think he ever had to use it for back up. I always thought it was funny when the hunters would put on their safari suits get a photo, their mountain man suit and black powder rifle, get a photo, and their camo and fluorescent orange for another photo, all while my uncle would be sitting over there with his winch truck waiting to haul the carcass back to the cold storage.
