A writer from Mother Jones magazine has posted this report about attending a gun building party in California. According to his article, these 8-hour classes are relatively common, and in just one day, attendees can walk away with a fully-functioning, totally untraceable, AK-47 assault rifle. And, because the guns are assembled from individual parts and are just for “personal use,” the serial numberless weapons are completely legal. The gun build parties use legal loopholes and slight design modifications to allow students to own unregistered assault weapons, even though—as the reporter found—law enforcement agencies didn’t seem aware that such parties even took place. In many states, the homemade guns can be sold without any background checks or documentation. Those one-time use, 3-D printed guns suddenly seem a little less scary …