A working 1/72 scale cannon especially made from that kit is smaller than I thought possible - please provide details of how you did it.
The smallest one I made was akin to a .22 and used Black Powder. The thing would jump violently and I would be terrified when igniting the fuse.
The problems I had were with powder had initially used my own home made gunpowder but it caked badly and would not ignite when in small amounts so when I had a friend give me some black powder that worked a treat. The other problem was the fuse being small enough especially given the size of the hole to access the powder charge, eventually I had to make the hole larger than what was in scale with the model.
Anyway it could fire a small ball bearing deep into a water melon at 3 metres so I was happy with the results... What ammunition if any are you using?
Basically itīs a bit of brass tubing. I used a hacksaw to make a groove across the tube and then drilled a hole in the middle of the groove, one big enough to take the fuse that Comes with the average firework. Cut a banger in half, take out the powder, put that in the tube, wad it with some tin foil, stick the fuse in, light and retreat to a "safe" distance.
The tube, being covered in Card is glued to the base with pattex, any gaps filled with PVA and sand.
Ammo, I didnīt use any this time, would be a wooden bead.