Got it a couple months ago, a little too big for EDC.
How the heck did I miss your post! And how the heck did I miss the Vinwiki video, I watch those vinwiki's a lot and a slew of other car channels.
My grandfather was a ship captain. He had this little brass/bronze deck cannon for defending against a boarding party. You'd pack it with nails, glass, whatever you had and it would be a giant shotgun. Some might be tempted to call it a signal cannon and I'm sure it was used for signaling but it was clearly meant for defense. The bore was about 1-1/2", much larger than a signal cannon would have had and the barrel was barely above level with no height adjustment meaning it wouldn't easily fire over the rail on a deck. Really only good for blowing out knees and feet.