I have a CZ 12ga/7x57r and have never even considered that the barrels should be 'regulated' in any manner. I shoot the shotgun at shotgun ranges with shot using the front sight and shoot the rifle at distance using the scope. Have never even thought of any thing else till this thread. I can't see where they would EVER need to be regulated as are double rifles. I treat it as a single shot shotgun and a single shot rifle.