Hey Fiddy, have you fired one of your cannons yet?
What are you using as a charge? did you end up going with the powder out of flares or the ramset charges?
I remember I found a full box of ramset charges. I then preceeded to have fun with them. I carefully removed the waxy wadding from the end, placed one on the concrete, tilted it up a bit so some of the powder made a powder trail fuze, and lit it. The powder trail would burn into the casing, reach the initiator, which would then detonate with a resounding bang.
Further down the track (when you could still buy bullets and shells in the sporting goods department), I got some 12 gua ammo. Did the same thing. Got the shell open with a pocket knife carefully, removed the buckshot, made a powdertrail fuze and lit her up. Needless to say shotgun powder burns quicker than ramset charge powder, and it went BOOM. My ears were ringing, and I only did one. I put them away until I discovered potassium permagenate and glycerin - the poor mans slow delay initiator. Gave me heaps of time to get well back and not be deafened by the bang the initiator in the shell produced. 22 round's also make a good bang as well. For those I'd grasp the shell, and remove the bullet with a pair of needlenose and repeat the above performance. The shotgun shells were the loudest.
Then I discovered what fun can be had with sparklers.... lots of sparklers... in a confined space (can you say KABOOOOM!)
Anyway back o/t, I want one of these cannons just to sit next to my computer or TV. They simply look cool, let alone the fact that they are an actual working cannon