https://techcrunch.com/2018/07/10/court-victory-legalizes-3d-printable-gun-blueprints/

A multi-year legal battle over the ability to distribute computer models of gun parts and replicate them in 3D printers has ended in defeat for government authorities who sought to prevent the practice. Cody Wilson, the gunmaker and free speech advocate behind the lawsuit, now intends to expand his operations, providing printable gun blueprints to all who desire them.

The longer story of the lawsuit is well told by Andy Greenberg over at Wired, but the decision is eloquent on its own. The fundamental question is whether making 3D models of gun components available online is covered by the free speech rights granted by the First Amendment.