What projectile for buffalo shooting with .25-06?

120 grain Nosler Partitions or Barnes Triple Shocks would top the list. Nosler Accu-Bond,Hornady SSTs or InterBond,Sierra Game Kings. What you are looking for is a bonded core or controlled expansion bullet to provide optimal and weight retention. Most Ammo makers are providing a premium bullet these days. A standard cup and core bullet has a tendency to shed weight as the bullet travels inside the animal so suffers. The Barnes and the new Nosler E-Tip use only copper alloy and open up petals to make wound channels and retain near 100% weight.