have you bushed your firing pins yet? Bushing the pins is a must. The Smith would not be my choice for these kind of pressures....I would want to be a longway behind that test fire jig. If the action and lock up hold to your test firing you should be able to tell if has been affected by examining the lock up to be sure that nothing has loosened. I know shot gun bores are usually measured before and after proofing...I don't think that the barrels themselves are your weak spot. I would be concerned with the locking system most of all on this project. If I personally was going to convert a smith to a rifle, it would be a rifled 20 ga shotgun, much lower pressures and about the same power as a 30-30. Good luck and be very, very careful.
Steve
