Yep, when there is an explosion, or even worse, a series of explosions, the cops come. It's what cops do. That is especially true in a heavily populated area such as in town or near a housing development. Several years back, I made a carbide cannon out of 4 inch PVC pipe. It could make a pretty good noise. Sure enough, the cops showed up and were pretty serious about what I was doing. One of them began to tell me the penalties of discharging a firearm within the city limits. I pointed out to him that it was not a firearm. That resulted in a discussion between the two cops who were there and they had to make a couple of calls to the station for clarification of the device that I had been using to make the big booms. They finally decided that they would not cite me for discharging a firearm within the city limits but were going to issue a warning for disturbing the peace and told me to put up the "cannon" and not fire it any more within the city limits. After the professional part of their visit, one of them took an interest in my device, asked several questions and said that it looked like it would be fun to play with. I told him to come over one day and we would take it out in the country and fire off a few rounds. He said he would like to do that but he never did.
Another story. Several years back, there used to be a muzzleloading range and gun store in Pasadena, Texas. It was a huge store and sold all kinds of muzzleloading rifles and equipment. One day, they got in some Coehorn morter replicas that were capable of firing soda cans filled with concrete. The owner had never fired or even seen a morter fired and wanted to see what one would do. One evening when no one was using the range, they took one of the morters out to fire it. Neither of them knew how to charge a morter so they looked at the big bore and decided to just pour in some powder. According to the owner, they put in about a pound of powder, stuffed in a soda can filled with concrete and lit it off. There was a huge explosion and they never did know where the can landed but the noise brought the cops. They knew the cops would be coming so the quickly hid the morter. When the cops got there, both said that they too heard the noise and wondered where it came from. The source of the noise was never discovered and the owner of the store decided to not fire the morters any more, just sell them. Within a matter of a few weeks, all 4 or 5 of the morter replicas were gone. Someone was having fun with them.
