Cody Wilson has a simple dream: To design the world’s first firearm that can be downloaded from the Internet and built from scratch using only a 3D printer--and then to share it with the world.

Before “three” arrives, a shot reverberates across the overcast central Texas landscape. A tall, sandy blond engineer named John has just pulled a twenty-foot length of yellow string tied to a trigger ...

The moment you finish setting up your first 3D printer, it may feel as though the entire world is at your fingertips. After all, you can craft all sorts of things, from handy tools to beautiful ...