A wooden stock can change due to weather. That's why a lot of guns are glass bedded or free floated.
Also, as Art said, the trigger guard screws can change the point of impact depending on how tight they are in relation to each other. You have to experiment with tightening and loosening them to get the best accuracy.
HTH
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Any fool can criticize, condemn, and complain, and most fools do.
Benjamin Franklin