I'm no expert. That could be a charge hole that you touch off with a match.
Still looks like it'd be fun to play with.
Most I've seen use cannon fuse. I used to know where t get some, but that bait and tackle shop closed many years ago now.
Yes you want to use fuse. Place fuse in hole, dump powder charge, then add wadding use a dowell rod to pack it down. Cut your fuse so there is about 1/2 inch sticking out top of barrel. I use waterproof cannon fuse that I get at a local gun shop. I have seen rolls of it at gun shows. I have also bought fuse at fireworks store, it is usually thinner than the stuff I use, but works in a pinch. You can also order it from Dixie Gun Works. You can also get the powder measure there. If you lived closer I would meet up with you and shoot our cannons together, but looks like we are at opposite ends of the state.
Do they sale fuse that small? I didnt see any on the website may have to do some more digging on that. You think it would be ok to shoot a projectile from it?
You could shoot a patched round ball from it. Hard to get any kind of accuracy, smooth bore, elevation adjustment is crude. I just use mine to make noise.