I helped shoot one a few years back, in the marsh and at 100 yards it hit a pine tree and sent the ball back over our heads just as fast as we shot it down range. we took the gun and threw it in the river. scared we would be drinking something good and want to shoot it again. it was a simple piece of pipe that we welded several layers of Pipe together and a end cap on, YES VERY STUPID. but we were just kids, and didn't know any better. kind of like the potato gun that we few with oxygen acetylene we are not sure where that potato went but it went out of sight and still climbing.
now we are a little safer.