The Liberator is a completely 3D printed single-shot pistol that can shoot 9mm.
The Washbearis a completely 3D printed revolver.
3D printed ammo is currently in development.
They aren’t very practical, but can likely go through metal detectors.
Neither will 99% of 3D printed guns. Most 3D printed guns use metal parts, and ammo will likely be detected as well. Only single shot, entirely 3D printed guns with plastic ammo have any chance.
Cheap items/electronics can be more expensive on Amazon than direct, though.
Amazon:
Direct:
You would need to put your keys in a faraday cage.
Distance doesn’t matter, as they can just use a bigger antenna or better amplifier. You find footage of people using large loops of wire to capture the signal from the keys