Cody Wilson’s first 3D printed firearm (The Liberator) was a dead simple design. A single shot device with crude parts and even cruder looks it nevertheless did its job: it proved the concept. The idea that a 3D printed gun could actually function was proven. Now, with the addition of a couple new metal parts, people are starting to 3D print their own firearm creations and the latest is a fully functioning semi-auto 9mm handgun. How cool is that!?
Some of the more astute readers might recognize that this is basically an AR-15 lower with a new plastic upper. You’re more or less right, but that still doesn’t change the fact that a 3D printed gun is handling the recoil forces without flinching. More info here.