I did this once and on purpose!! I started out with a load just strong enough to get the bullet out the barrel, then I used a towel wrap over the cannon that was in my shooting hand and yep, it fired, then increased the load until I got to a full load, then I stopped and decided I did not want to do it again. I read it once in a spy book and had to try it, I DONT RECOMMEND IT! Read about it here!
http://forum.lugerforum.com/showthre...ht=fire+cannon