All the way at the bottom of the page for you disbelievers...
http://www.atf.gov/publications/download/p/atf-p-5300-15.pdf
Sale of Business or Going Out of Business
You must give written notice to the Chief, FFLC, within
30 days after you sell or discontinue your firearms or
ammunition business. If you sell or discontinue your
firearms or ammunition business and are succeeded by
a new licensee, your firearms dealer records should be
marked to show this fact and must be delivered to the
successor. If you do not have a successor, you must
deliver all of your firearms records within 30 days of
going completely out of the firearms business to:
ATF National Tracing Center
Out-of-Business Records Center
244 Needy Road
Martinsburg, WV 25405
See how it works? They dont call it registration because at the moment it is illegal. They call it a "trace".
Brilliant aint it? That causes most Americans to believe that guns aren't"registered". Maybe I am simple. If the Feds know where they are at and who has them,for all practical purposes they are registered.