Nice pics, Tim. Wonder what people dining at the Burger King thought as they saw camera flashes in the near distance. You wonder if they were waiting for the Crime Scene Tape to be reeled out. You're a man on a mission, Tim. Thank you.
Mike and I found a 24-Pdr. Siege Gun, Pattern 1819, cast in 1827 at Fort Washington, Maryland on the Potomac River last fall. Sometimes you find cannons not as you expect them to be. I called Mike over to take a look as I got close to this piece which was on a Wood, Front-Pintle, Seacoast, Barbette Carriage, and saw the left trunnion face. See photos.
Tracy and Mike
The gun is mounted in a central position on the Terraplein high above the Potomac River.

This is the marking on the left trunnion viewed from the breech. WPF (West point Foundry) upside down. But why?

The reason for upside down mounting. A badly eroded vent which would allow rainwater entrance to the bore. The bore is sealed at the muzzle.