Ask on the Single shot forum. There is one smith that specializes in single shots but I forgot his name. I agree it is time to try a new barrel I don't know if you can tell by lot # but many of the red pad barrels were from Wilson and were not even as good as the ones the military got from them.

"When you disarm the people, you commence to offend them and show that you distrust them either through cowardice or lack of confidence, and both of these opinions generate hatred." Niccolo Machiavelli