LOL, I was part of a "Pirate group" that hung out at Ren Faire and drank too much. Once, during a group campout they had a canoneer(sp?) who brought a few small sample "rail guns" with him.
We had a pledge system where we tortured newbies for a year and called them "Step -N- Fetches" and made them.... well, step and fetch stuff.
Two funny things happened.... one, they fired wadding at a tree they had been firing at all morning with regular pistols and some black powder guns and the tree fell. (With no contact) Kind of classic, I thought.
The second was when they had a miss fire and after discussing the dangers involved with that the Commodore calls out "Steeeeeeep NNNNNNN Feeeeeetttcccchhhhh!!!"
[Edit] Ohhh, and on the canon build... I have no idea what safety protocols are necesary so I'll be passing.