See this is as much of a myth as the myth that more guns equate to more crime. No, most people don't know how to get a gun illegally. I do because I've grew up around enough criminal elements that I know where and how to get a black market gun without getting myself killed or arrested in the process. Most people do not....we are all missing an important point....and some are advocating for that which most of us abhor....more rules and legislation...does anybody here really believe that a person who has no intention of abiding by the system is really going to fret over some additional restrictions to gun ownership? The real psycho's who are hell bent on murder and mayhem has ready access to any weapon he or she chooses, and no law is going to stop that person from acquiring and unlawfully using that weapon.
If this kid bought his gun for self defense then he wasn't "hell bent on murder". He simply snapped and had he not had access to the guns he legally bought it's unlikely he would have been able to get his hands on them.