One thing a guy should never do is tighten scope ring screws during a hunt without going to the bench to check zero. Also the difference between Colorado and Kansas zero is 1.5 to 2" lower in kansas because of air density. This I have checked out personally. If you sight in for kansas you will be off in colorado. I make all my clients zero when getting to colorado for the hunt.Might explain alittle difference but not enough to hitas low as you were saying.Might have bumped the scope.