Part Time Chef made a working replica cannon that shoots harmless powder filled cannon balls – “Halloween has been a pirate theme around here for a while. I had the sword, I had the treasure chest, I needed a cannon. More than just a prop, this cannon will fire a potato slug a couple of hundred yards. For Halloween we dialed back the psi and shot harmless “cannonballs” made from tissue paper filled with baby powder. The result was a VERY popular addition to the pirate party we had.” – Link.