Swivel guns were the smallest type of cannon carried aboard naval vessels of old. They were most commonly loaded with grapeshot and used to attack would be boarders. They were also loaded with standard round shot, but this shot was almost useless against other large ships. These cannons did however, have the ability to be easily moved about the ship and mounted just about anywhere.
About this creation
These are the parts you will need:
I chose to upload this because it was one of the more interesting parts of my French cutter, and I don't think I've seen any others on the pages. Feel free to use it.
Nice gun, it looks like you could do a modification of the design to ditch the cut rod though. A different sized round pin would probably fit through the wrench just enough to hold the telescope piece in place. Just some food for thought, if you're running low on those rods.