Hi David,
This work of yours is very, very impressive. How did you dimension the powder chamber? I assume the chamber was solid in your cast set as it is in mine. Obviously, it has to be sufficiently deep to intersect with the vent hole. Did you drill the vent perpendicular to the chamber of angle it forward? Does the ball sit in a recess on top of the powder chamber? Will the barrel have a lug for a wrench or can you get enough grip on it to unscrew it without the wrench. Also, David, I am experimenting with variable thickness silver wire inlay to use on my current English rifle. I am trying to achieve the look found on guns by Barbar, Dolep, and Gorgo. That style of wire work would be perfect for your carbine. Hopefully, I'll can get it right but regardless, I'll keep you informed if you are interested.
dave