Um, how'd the kid get a fucking gun?
It's America. Where kids not having access to guns is the exception rather than the rule.
I must live in another country, because my ass would have been BROKEN by the time my family was done with me if I'd run off with a gun. The sheer magnitude of difference between the odd beating from some assholes and just what my family'd do to me if I'd taken a gun to them is one of the things that ensure it'd never happen.
Though perhaps being aware there was an entire magnitude of pain well beyond a couple bullies is why I take them relatively lightly.