"Glock switches," small devices capable of turning almost any handgun into a machine gun, are increasingly being found among seized firearms in the Phoenix area, according to the Bureau of Alcohol, ...

Part of the gun that the police believe was used to kill the C.E.O. of UnitedHealthcare was made by a 3D printer using a popular design found online. By Thomas Gibbons-Neff and Aric Toler At first ...