Before I got around to proper black powder cannons I made a really large carbide cannon with electric ignition. It shot apples really well. I later attached a tank of hydrogen and was able to achieve fairly rapid rates of fire. One evening the local police came by and confiscated it.
My dad had to pick it up at the station a few days later, giving a promise that I’d only shoot it in the daytime. He said that it was quite the talk of the station.
My fraternity had a black powder cannon. Took some oil field casing pipe with an interior diameter about same as a beer can. Two wagon wheels and a realistic carriage. Mostly we would fire blanks but it would launch a concrete loaded beer can about several hundred yards.
Our tradition was to celebrate a brother’s betrothal by marching to his fiance’s sorority pulling the cannon. Torches, rebel flag, quite impressive. We would serenade the fiance, finishing with Old Dixie (the slow version) and firing the cannon.
That was the sixties. Imagine the Social Justice Warriors and Cupcakes if that happened today.
From the responses, it seems to be a basic characteristic of Freepers when young - they liked to experiment with things that go “boom!”
Poked a hole in the side of a gallon milk jug then added Calcium Carbide and water. Lit a match close to the hole and squeeze the jug. Nice flame squirting out about 12” long.
The deign error was when the squeeze on the jug was released the flame got sucked into the hole and BOOM!
My ears rang for days.