I say put the bullet into the lungs and you'll have a dead deer.
Yes!!!!!
Since 2000 nearly all my deer were killed with a muzzleloader, many with the TC Black Diamond. Be prepared for a deer shot through both lungs to run a ways. Sometimes a deer will bang flop but that's not common unless there is CNS involvement.
Last fall i killed a huge buck with my ,50 TC Black Diamond and a 250 grain SST bullet. Deliberately shot the deer in the shoulder because the property line was close by. That did not work so well because the deer hunched, took off and ran 70-80 yards-fast. Watched the deer run off and heard him crash.
Bullet did not exit and lungs were hardly damaged. There was a 2" diameter hole in the chest wall. Bullet fragments tore up some blood vessels. The deers chest cavity was full of blood.
IME: When used against deer and hogs, .50 and .54 caliber muzzleloaders are as deadly as a .30-06 and 150-180 grain bullets. Properly placed .50 and .54 caliber round balls are as deadly as saboted or conical bullets.