David, I had another thought that could be an easy start point for investigation. I call it the "Closed eye test" With your O/U(unloaded),that you are shooting well, focus on on a target point and shoulder the gun to the target. Sense where the stock touches your cheek and chest. Do this again with your eyes closed then open them to see your target hold. Remembering the cheek/shoulder feel try this again with your SXS. Perhaps this will tell something? This won't say where your gun is actually going to shoot(poi)but it may help evaluate the situation?
