A good sniper or any marksman knows where the arrow or bullet will hit. You should also know the muzzleloader’s trajectory being a hunter.
At a close range, we should consider a zero that lets us hit a target without thinking about holdover. This is what you call a point-blank range. The point-blank range will establish the right zero distance.
Using a 6-inch mark, for instance, you need to know at what range you can zero your muzzleloader or where the bullet’s trajectory won’t go outside the selected range. Generally, it is three inches above or below the reticle. Therefore at 100 yards, the impact will be 1.75 inches above the centre of the reticle. This is 100 yard zero distance.