Here is a barrel that is perhaps useful as a replacement or a build. It is 10” long, 13/16” bf. Set up for flintlock, not drilled. That part could be removed and a drum used. I do not believe it was used/fired, however, there was storage rust as well as a coat of paint which I removed. The bore feels smooth when a cleaning cloth is ran through it. $30 plus flat rate postage of $12 money order, personal check until clear or pp f&f only.