i want a cannon. not a full size cannon (wife said no) but a small, black powder cannon. i dont want to to shoot projectiles, just to make a blackpowder bang & smoke. it has to be smaller but not tiny. i want to mount it on my pontoon boat. i also dont want to break the bank for this thing. i even considered looking for an old black powder rile and chopping it down then building a fake body around it. any suggestions?