I've had some similiar issues in the past as well. If it was okay before, I would check everything over real well and make sure it's tight. Base, rings, etc. If it was holding zero & grouping well before, it sounds like something may have worked loose. I started using my TC Omega .50 for firearms season here in Indiana. Just because it so much more accurate than my Mossy500. That way I can just leave it set up for turkey hunting and switch out barrels if I want to hunt rabbits.