I have killed woods bison with a 250 gr Barnes X in a 375 H&H, one shot. My buddy did the same with a single 300 gr Hornady RN, ancient production, not Interlock or Interbond.
My wife, however, shot a massive bull with her 30-06, two shots, 180 gr Kodiak Bonded Core bullet. Northman999 and BigUglyMan have both seen the mount.
You have to hit them very low, right behind the foreleg, if broadside. Otherwise they will travel for hours, and go a long ways, as attested to by many hunters who have hit them otherwise.
Ted