It sounds like you may have a parallax problem.
Put the gun in a vise or on a steady rest.
If you look through the scope and move your head side to side without moving the gun so that the dot moves within the field of view, does it stay on the same point on the target, or does it drift with your movement?

If it does move, that is paralax, and you can minimize it's effect by making sure that the dot is in the very center of the field of view before you shoot. It should get you through the season anyway.