This is a great example of technology subverting law.  3D printers were developed for all sorts of practical purposes (rapid prototyping, replicating out-of-stock parts, etc).  But it turns out, 3D printing can also be used to print guns and gun parts, thereby circumventing gun control laws.

What can government do to restrict this?  They could outlaw the printing of guns and gun parts, but this would presumably be very difficult to police.  They could restrict the sale of 3D printers entirely, but this would seem to have a disproportionate adverse impact on the numerous “legitimate” uses.

The article mentions that the “lower receiver” is both the only part for which a license is required and works if made of plastic.  That makes this method perfectly suited for subverting gun laws.

My guess is that the government will respond by making more gun parts require licenses to purchase.  I’m not sure who will object to this path, or how much political power they have.