Dom, thanks. I ran into a somewhat similar situation before when I posted similar characters found on the underside of a Lantaka which came from Midinao, Philippines, although I cannot recall the exact response, would have been on this forum maybe 3 years ago.
The type of cannon on which this inscription is engraved is a form of Spanish cannon which was cast in the Spanish-dominated Philippines during the 18th and early 19th Centuries. A couple of examples can be found in Brinckerhoff's SPANISH MILITARY WEAPONS IN COLONIAL AMERICA 1700-1821. My theory is that these small cannons (most seem to be between about 2 and 4 feet in length) were cast for Spain by small bronze foundries in the Philippines, under contract to Spain. There was a major Spanish cannon foundry in Manila, apparently associated with the Manila Arsenal during its operation by Spain, but I think its production was devoted to larger cannon, say three-pounders and upward to at least 24-pounders.
I've been in contact with Sid Brinckerhoff, author of the book mentioned, who is also trying to learn more about when and where these small Spanish cannon were cast. The big question is whether their production was limited to the Philippines, or whether they were cast in North America and/or South America as well. I don't think any of these smaller-bore bronze Spanish cannon were cast at the two Royal Cannon Foundries in Spain, namely at Seville and Barcelona.
BTW, here's the old thread where I asked for a translation of Jawi on the Lantaka, and was told it was not Jawi, but was non-Arabic language using Arabic characters. Does anyone have a name for this language or script?
http://www.vikingsword.com/vb/showth...light=cannonmn