I recently acquired a pair of guns made for Orvis by Union Armera. They are marked M 215. They are both little used. The number one gun fires and ejects both barrels fine. the number two gun opens and ejects well independently, however, when both barrels have been fired, it is very difficult to open. It takes a lot of force. The spent shells eject perfectly timed. Could it be that the number two gun need more time to break in having not been shot nearly as much as the number one gun? Ideas? Am I damaging anything forcing it open?