In this day and age, 3D printers have enabled us to mass-produce an enormous range of items without even leaving our homes. However, this presents some problems as well. Regulation will not apply 3D printers as the laws stand.
As such, let's apply some of our current regulations to 3D printers. A national database of printers would mean that if printed guns were used in a crime, police would know where to start. Background checks on those who buy them, to see if there is a history of gun violence, could be installed.
There have not yet been any shootings with 3D printed guns. Let's do our best to make sure there aren't any in the future.