Hi Guys,
I'm here on Viana's referral. I got the "trombon" along with a Spanish pistol, both have identical ramrods, and I naturally assumed they were both Spanish, specially on account that the BB's barrel has the remnants of what seems to be the Spanish Royal arms seal at its top. Then I read in the book "Small Arms of the Spanish Treasure Fleets" that the Spanish never made brass BBs. That started the ball rolling. OTOH, the same book states that the Spanish didn't have any official issue curved blades until 1806, and I know that the Spanish Hussars of the Reyna and Espana Rgms. wielded a curved sabre very much similar to the M/1780 during the reign of Charles III.
Coming back to track: The ouside diameter of the barrel's end is 2 3/4". This BB, as originally found, had a thick whitish fungi coat on one side, and a mix of rust and brass patina everywhere else, which I was forced to clean.
I have seen the very same BB at a local library's book, but they haven't allowed me to photograph the page, nor is the pic specifically IDed.
Check the following pics, and no, I haven't yet disassembled the lock yet, but I intend to do so very soon.
More pics (if you'd like to see them larger, the image depot is at
http://s353.photobucket.com/albums/r371/runswithswords/Naval Blunderbuss 18th C/)