I have only shot 3 Bison, hardly enough to make me any kind of "expert" on them. I have been along on several other kills as well.
Personally, I would choose the 338 Win Mag. [I shot 2 of mine with the 338] I shot one with the 210 Partition, the other with a 225 Partition.
The third was shot with the 308 Norma Mag and the 200 Partition. All these animals died fairly quickly, and without fanfare.
The anatomy of the Bison makes shot placement important. The first instinct is to shoot center of body mass below the hump. If
you do, the shot will be too high, and may miss the lungs entirely without hitting the spine. Lower third is better, up close to front leg.
On one Bison hunt, where I was an observer, the animal was shot 6 times before he was finally down permanently. [300 Win Mag, 180 gr bullet]
But in fairness, it was not the chambering, nor the bullet at fault, it was proper bullet placement, particularly the first shot.
They can be tough, and are large animals....better to have enough gun.
Regards, Dave.