Bill: There is nothing dangerous in shooting black powder or it's equivalent in an antique percussion or flintlock double gun as long as the barrels are sound, not badly pitted and have sufficient wall thickness. I have never heard of barrels being brazed to the ribs only soldered. You are correct that most American makers imported the tubes from either England or Belgium. As far as I know all British barrels had to pass proof in order to be sold.

Best Regards, George

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