In the summer of 2024, former Army National Guard member Andrew Scott Hastings spent a sweaty afternoon carefully packing boxes with parts he made using his 3D printer. These weren't novelty figurines or replacement Ikea pieces. The boxes were instead filled with a handful of homemade firearm lower receivers and more than 100 "switches," small devices capable of converting a semiautomatic gun into a fully automatic weapon. Their intended recipients, federal prosecutors allege, were al-Qaida oper