Regardless of the state of any other gun control laws, it's almost certainly going to have to be illegal to 3D-print guns once 3D-printing becomes widespread.
How do you enforce such a law?
I don't know. I guess all 3D-printing will have to be monitored by the government.
3D printing of things we don't want is coming. It will be as easy to stop as illegal file sharing has been (meaning it won't be stopped). You can try and pass authoritarian laws to stop it, but it won't stop it anymore than your authoritarian laws stopped prohibition of drugs like alcohol, coke or weed. Sure, a nice machine is still $10k and the materials are still lacking in the durability department, but prices always come down, technologies continue to mature.
All gun laws become irrelevant if you can just print out any kind of gun you want. I agree that the price will come down dramatically, and the quality will come up, probably revolutionizing the world on the level that the printing press did.
I'm open to other ideas -- I'm just not sure what else could possibly work.
