Whatever people in power try to stir up about this, it’s literally impossible to legislate and block shapes from being 3D-printed. Any attempts to do so are a fool’s errand, and/or just being used to justify misguided attempts to lock down 3DP technology for other reasons (read DRM/copyright forces in big business.) Blocking parts that might be for a gun from being printed simply cannot be done.

blog.adafruit.com/…/what-a-load-of-filament-the-c…

michaelweinberg.org/…/3d-printer-gun-screen/