ATF Hands Judges Loaded Weapons—And Lessons to Ponder on Bench

Before a group of judges and attorneys stepped into a Texas shooting range last week, the Bureau of Alcohol, Tobacco, Firearms and Explosives sat them down for a little chat.

The presentation was titled “Privately Made Firearms,” a reference to the kinds of guns and components that can be made at home, without the tracing elements like serial numbers that can help law enforcement figure out the source of a weapon.

Attendees got to watch a 3D printer put out a component that can rig a gun to shoot automatic fire, and even a couple videos showing automatic weapons in ...