From Bearing Arms:

People have been able to make guns for years now. Hell, my first AK was built in a buddy’s backyard from a kit, back before the ATF decreed that barrels had to be destroyed prior to import. Was there a serial number on it? Sure, but only because I put one there.

For all the wailing and gnashing of teeth from anti-gunners, literally nothing changes. In fact, access to this technology may actually make people safer.