I usually bore sight, if you can, not workable for revolvers & autos. Then I shoot at a big peice of cardboard with a target dot in the middle. I check where the bullet hits, then clamp the gun in a shooting vise, take off the turret caps, clamp the gun and adjust to the original point of aim. Then I move the crosshair to the bullet hit. This is tough to do without moving the gun, but do the best you can. Once the crosshair is where you want it, tap the turrets lightly with something nonmarring, I use a loaded 12 ga. shell and tap with the crimp end. Then I set the gun up and shoot another, this will usually get you in the ballpark and you can make the final adjustments with the turrets.