As new 3d printers become more and more affordable they will change the way that we think about many products. Now that the first 3d printed guns are available the regulations about how to handle 30 day waiting periods etc. will have to adapt or become obsolete. Get the story here:
http://www.extremetech.com/extreme/133514-the-worlds-first-3d-printed-gun
in a related story, 3d printers can now print DRUGS!