David Wirth 3D printed a 20lb railgun that fires copper-plated tungsten slugs with 1,800 joules of energy, firing them at 560mph, with so much force that they vaporize on contact with a steel-backed target.
The gun uses an Arduino Uno R3 to monitor charge levels across its six capacitors.
The resulting design was complex enough that he even made a 3D CAD drawing that would do DARPA proud (above). The test shots with graphite and aluminum projectiles were far less lethal than a regular gun, as you can see in the videos below. Nevertheless, the aluminum "bullet" still put a half-inch dent in the steel-backed plywood target, and the graphite projectile "probably just vaporized," according to the Wirth.
Guy creates handheld railgun with a 3D-printer
[Steve Dent/Engadget]