As a kid we built a potato gun using a four foot piece of three inch pipe and an end cap that screwed onto the pipe. We drilled a hole right in the center of the end cap. To load the gun you would place a large potato on the street and hammer the pipe down on top of the potato filling the pipe with an air tight potato slug, then stick the fuse of a cherry bomb through the hole in the end cap and screw it on the pipe.
One person would hold the pipe on his shoulder like a Bazooka and aim it while someone else would light the fuse.
The first time we fired it was at a target taped to a wooden stockade fence. We were quite shocked when the potato went through the target, through the fence, through the neighbor’s kitchen window and lodged in the wall on the other side of the room.
We ran like hell, hid the potato gun and hid out for a few hours before coming back to find the police combing the neighborhood. For some reason my little circle of friends (we were all ten and eleven years old) were never suspect although they questioned our older brothers (that was over forty years ago, I hope there not still looking for us!) We only used it a couple of more times but really not having much use for that kind of fire power and not being overly destructive kids we soon lost interest.
I can still remember to this day how surprised we were at the power of the thing and the adrenalin rush as we ran off to hide.