Building Your Own Untraceable AR-15 'Ghost Gun' Is Easy

Gun control advocates — and gun lovers — talk about "ghost guns" that are made at home and can't be traced by law enforcement. Andy Greenberg made in his office at Wired. It's a metal AR-15, that required no waiting period, no background check — and no serial number. This summer he wrote extensively about it in Wired and he told us the story, beginning with just what he means by "ghost gun."