A cannon!! :) that works. Im not responsible for any injuries or damages...so there is no confusion, yes, i have fired it no problems except the barrel gets full of paper and needs to be cleaned after each shot therefore i recommend gunpowder but i havent tried it.

Don't use the Gcode files! they shifted the print and are for a heated build platform and ABS. I posted them here for my sake. Print out each part starting with the barrel, moving to the holder, and then the base. These will all take a while to print. After drilling out the barrel, sanding the outside down and the inside of the holder fit the 2 together and place in the base. Load the firecracker fuse first so the fuse pokes out the hole in the back and FIRE! depending on what you use this could be really dangerous.