The fact that just one of them had a gun and he was letting the other kids examine it made me think that he had his dads gun, without permission of course.
Or that he was a kid showing off his toy, sheesh, you must live in a bad neighborhood to be so negative.
Actually I live in a very quiet upper class area. Children with weapons on the street are a very unusual sight though.
Just guessing, but I would imagine at least 50% of my neighbors have firearms. A few that I know have nice collections.