I've shot deer with a muzzleloader that dropped in their tracks then shot some that ran off with out dropping any blood and help track others with no blood trail so I really don't trust sabot bullets a 100%. That why this smokeless muzzleloader is interesting with the higher velocities but I would probably choose the 250 gr.
Not leaving a blood trail has nothing to do with the bullet or sabot combo.
Shoot high, the blood pools into the cavity.
Shoot the heart, there is no capacity to pump blood anymore.
Death is cause by lack of blood to the brain.