Ioan Grillo, a Mexico City-based author and journalist whose stories on crime and gangs have been published in the New York Times and National Geographic, chats with Trey Elling about BLOOD GUN MONEY: HOW AMERICA ARMS GANGS AND CARTELS, including: the histories of assault weapons, the NRA, and gun laws; how legal guns end up on the black market and in America's poorest communities and trafficked across the border to drug cartels, mass shootings in the US, 3D printed guns, and more.