Police said Luigi Mangione, the man charged in the killing of UnitedHealthcare CEO Brian Thompson, appears to have had a ghost gun, a weapon that can be made using a 3D printer.

Pump guns are largely American guns. The rest of the world prefers semiautos and break-actions. Of the three main action types, pumps are the least expensive. They are often the first guns ...

As for the 8x22mm cartridge, it’s a rimless bottleneck cartridge with a diameter of 0.320 inch, generating a muzzle velocity ...