Very nice looking piece! If you plan to fire it, I suggest you take it easy with the load and get some expert advice on recommended and maximum powder charge, but I have a feeling this is not your first black powder project and likely you know more about this than I do. Just out of curiousity, what caliber, and is the barrel tapered? Can you open it from the breech, for pass-through cleaning?

I never messed with a matchlock. Built a pair of .58cal flintlock pistols from a kit, a Walker Colt kit, and a Remington 1858 New Model Army cap and ball revolver from a kit, and I have an 80% 1911 kit waiting for me to find time to start building, but I have never built a gun from scratch. I don't have a milling machine or a lathe so it would be a bit of a PITA but I would like to try some day, maybe starting with a piece of a modern rifle barrel and turning it down. I bet a piece of a shot-out .50 BMG barrel would make a nice big bore black powder pistol. Lots of nice strong steel to work with, there.

Anyway nice looking gun, and thanks for posting. You may have inspired me to jump down another rabbit hole.