When I got rid of my FFL after 27 yrs...I had to send the bound books and the 4473 forms to the BATF in W Va. They keep them there on microfiche or some such thing. I was told that they keep them forever. That is registration by regulation. I sent them all the information that they needed to have. Scarey if you know what I mean. Dealers have to keep their records for 20 yrs
