I know of a number of hunters that have taken bison with a .30-06. It may be over 100 years old but that old cartrige is still going strong and I believe that the only one that has outsold it is the old .30-30
If a .30-06 is what you have available then by all means use it. It has more than enough power to take down a bison and a lot of other animals.
I just said in your other post that I like the 340 Weatherby but it is over gunned for a lot of the North American animals but so can be said of just about all the magnums out there. I also have a 30-06 that I used to take a lot of animals with. Mostly deer and elk and I never had a problem with it when I did my part on the shooting end of it.
i shot a huge buffalo bull with my .30-06. the first shot was thru and thru between two ribs on both sides, but got the lungs. the second shot may have missed but he only ran about 40 yards before going down. he weighed close to a ton. i shot a cow (meat hunt) with the .300 magnum. i actually saw it lift her up, thru the scope, off the ground at 90 yards. she only weighed in about 600 pounds. so yes, i would use my .30-06 again.
As I sit and glass, which is common for hunters out west, I have sort of quickly discovered something I never learned when I was younger.
In my youth I had enthusiasm and spirit. In my middle to advancing years I have creaky knees, arthritis, and I tire more easily than I used to. Where I used to sit on the cold hard ground I now look for that soft spot to sooth my tired muscles. That leads me to my tip.
Carry your soft spot with you!
In my pack I carry an air filled, ultralight, camping pad....