You have me interested in what you did to regulate the shotgun barrels. Every so often I come back to the idea of putting sights, sling studs, etc. on a double- but I never seem to get by the regulation issue. I seem to remember some time ago reading about at least one that had been regulated by judicious removal of metal from the inside of the muzzles, I have not tried this myself but I can see how it could work. But what you described, assuming I understand it correctly, is interesting. When you say you used a wedge, are you saying that you did not separate the barrels? And that what you did was, in effect, add weight to the left barrel with the wedge and that by moving its location on the barrel you changed the impact of that barrel? I see how this might work, I just want to be sure I understood you correctly. Your experiment has provided me with some food for thought.