I think it was 1948 when my father gave me a Big Bang carbide cannon. We shot it once in the living room and it sprayed dirty water out onto the rug. Mom said no more of that.
In 1952, I built a Marine Model Co. non-firing brass barreled Revolutionary War field gun kit. I drilled the bore and vented it in 7th Grade shop class. Scraped the explosive out of some paper caps and loaded it with a steel BB. We were temporarily living in a college dorm room on the same floor with a radio station's studios. Of course, I waited to try it out until I was alone in the room. It was quite loud and I have always wondered if the shot was heard on the radio. The people out in the hallway made it clear that they heard it ("What was that? I thought the building was coming down!"), but I laid low and never mentioned it to my parents.
Cannons are fun.
Larry