Tuan, please dont post sensationalist rubbish.
There isnt a 3d printer in the world that can print a firearm.
What the guy printed was a handle for a gun, not a barrel, endstock or ammunition which are all necessary parts for a firearm. I doubt anyone would bat an eyelid if he'd printed a handle for a bow, or a survival knife.
Here in the UK, we have heavy restrictions on firearms and yet that piece of work wouldnt be illegal here ON ITS OWN - Police finding a cache of these gun parts, or along with other components might have reason to believe it was more than just a model of a part of a real weapon, but on its own its just a piece of plastic.
A reasonably skilled carpenter could have made that part from wood, and it would be just as functional. It doesnt even have to be the same shape, just have the appropriate mounting points, and lever mechanisms to operate as a trigger. Guns are ridiculously simple to build and modify from a mechanical standpoint - what isnt so simple is the traditional techniques and mechanisms used to build them, aka what makes a gunsmith an artist.
Besides all this, it isnt guns that kill people, its people that do that. And with many things that arent even weapons...
