The revolutionary concept of 3-D printed firearms has been building momentum for months now. Online observers, innovators, investors and the generally curious celebrated as the first completely 3-D printed handgun became a reality. Since the blueprint for “The Liberator” hit the web, the file was downloaded thousands of times in just a few days. Today, the government shut it down. Cody Wilson, the 3-D gunsmith, law student, and founder of the non-profit innovation outlet, Defense Distributed, broke the bad news in a tweet to his followers.