RE: Ultimate Bison/Buffalo Round?
I look at this three ways.
For more a traditional shot. A in-line muzzlle loader like a TC Encore shooting a 300gr bonded shock wave with the most accurite max load. It would be scoped with a 3-9 power with a bullistic plex type reticle. This will be on par with the 45-90 and 45-100 sharps that killed thousnds of them.
Next a the big bullet aprouch, A bolt action Rem 700 CDL with its 24" barrel in 35 Whelen using Nosler's 250gr partition ammo at 2540fps. It is a 300 yard bisin killer. Sighted in for 200 or 250yards its gonna punch right through. And would be my top pick.
Last would be the High velocity apourch. The 338RUM with 250gr partitions. There is no dout this will work if you like the punishment!