It could also be set to a different parallax setting. I believe most muzzy and shotgun scopes are set up for 75 yards while the rifle scopes are set to 100 yards.
Knight MK 85 Stainless camo composite 54 cal
Savage 10 ML II pre-accutrigger Stainless Laminate
Knight Disc SS black composite 45 cal
Knight Disc Extreme blue/black composite 45 cal