Zulu, That type was identified as an insurance gun in a post we did back in 2007 when we went from Cape Cod, Mass. down to Fort Phoenix near Fairhaven and New Bedford, Mass. After exploring the fort, we visited the New Bedford Whaling Museum, a fascinating place where we spent an entire morning. While up on the third floor which surrounded a large atrium where there was displayed a 3/4 scale whaling ship with large copper rendering kettles and all, I spied a roped off area and what I thought was the outline of a cannon tube.
Discretely stepping over a large museum rope, I found myself in the museum's "back room" where they store all the politically incorrect stuff. Amid this jumble of neglected artifacts, I spotted the cannon tube. It looks like a number 54 where yours has an eagle, but the profile and "PROVED" casting is identical. If I owned it, I would not fire it, as it is a relatively thin tube without a steel safety liner.
Tracy
The Whaling Museum insurance gun.
The museum entrance in the quaint town of New Bedford, Mass.
