LS, from one of the links,
http://bna.bircherinc.com/cannontypes.htm. See last 2 sentence's. Have no idea as to the shop and prices but they seem to want to play. I have the same need for machine services on my Parrot tube. Something about adding more steel around the breech and the 1 caliber rule. Just sent an PM to see if they are interested and how much. Will let you know when / if I hear anything. VA.
ALSO AVAILABLE FROM BEAUFORT NAVAL ARMORERS:
Custom made brass accoutrements such as ramrods, vent picks, worms and ball moulds.
Extra Rail bushings for swivel guns.
Custom made re-loadable brass shell casings.
Wooden carriages, custom made for all size barrels, superb craftsmanship.
We recommend that you purchase your black powder supplies and blank gun shells from a gun dealer near to you, but B.N.A. can sell you these supplies.
Do you already own a cannon that needs repair? Service, repairs, and reconditioning are available from B.N.A. for other antique or modern cannons, ordnance, and firearms.