The fact that he was able to get his hands on a gun is fairly disconcerting. Not to piss on the right of Americans to bear arms, but this probably means the parents or whatever other instance the child depended on didn't properly secure their sidearm of choice.
While I understand that this right was given to Americans so they'd have tools to fight tyranny and oppression, I'm a little concerned. I've known a few friendly gun nuts in the past, and I just couldn't wrap my head around the purpose of owning a 50-caliber if you owned it for the sole purpose of crossing State lines once a year to go shoot out car wrecks.
If that's all you do with it, then you probably shouldn't own it. It's too much firepower in the hands of a single household. Granted, I'm one of them Commie Canucks, so I haven't seen hide nor hair of a hunting rifle since my early teens - and even then, seeing the thing with the safety on intimidated me so much I treated my uncle's rifle like it was some sort of death-radiating implement of doom (i.e. I avoided the very room it was in).
As for the kid; it indeed seems like it's some kind of attempt at grabbing attention. Either that, or it was your classic "I hate my life and you're all fucking jerks, so THERE!" impulse.