Rob, you might want to have someone check out your chamber size, L.C. Smith did not offer the .410 until 1926. If you could post some close-up pictures of action, and water tables of receiver and barrels, I'm sure we can help identify your guns. Both of your guns in those grades with ejectors and steel barrels is a good find. As far as shooting modern ammunition, I would try to stay under 8,000 psi for both. Use low pressure shells, a few companies make them, and if you type in low pressure under search, you will find references. Good luck, and hope you will become a member of the LCSCA.