[mountainlion]

I was thinking of a single shot zip gun.

[LouAvul]

I'm thinking of a Glock. Only the frame isn't available via mail order. But it's made of composite and from the article, this 3D printing device could easily duplicate it. All the other parts are available as aftermarket items.

I don't know what the big deal is. Only law abiding citizens have to jump through any hoops to buy a weapon, and they're not likely to do the 3D thing.