...without adult supervision - maybe there is a reason for it. I tend to think that at least one young man learned his lesson. Watch the video and see if you agree with me on that.
In a way, I have to hand it to these kids. They were quite enterprising, that was a neat looking project. I have to slam them too since it seems (it sure looks real to me) they were pretty careless and rather ignorant, and totally irresponsible, in how they went about manufacturing their version of a black powder rifle and in how they demonstrated it. Not wearing eye protection or hearing protection could have cost the shooter dearly. For all we know, maybe it did at that. I would hate to have had my eyes subjected to that back-flash. If he was lucky, he blinked in the nick of time but it sure happened quickly.
Those kids sure looked old enough to have known better. Then again, I sort of, kind of, somewhat vaguely recall having been young and dumb myself - once upon a few decades ago. So, I can understand why they did it. If his eyes did not get burned, nor his face too badly, then they probably had fun or will have fun recalling their mischief at a later date (if they are ever allowed to hang out together again). Truth is, they probably could have had, and should have had, fun in a much safer manner. In fact, they still could have had it with a gun if they had some responsible adult supervision. My closing thought: I would bet, if the shooter had parents who taught him how to be responsible with guns and still have safe fun with them, that whole misadventure probably never would have happened nor even crossed their minds as a passing whim.
All the best,