We have many requests for answers on how to deal with machine guns and other NFA items owned by a relative who has passed away. The BATFE has written an open letter on the subject which can be found here: http://www.atf.gov/press/releases/1999/09/090599-openletter-nfa-estate-transfers.html I've bolded the section having to do with UNREGISTERED weapons. I will add that, especially since these firearms are extremely valuable, if registration paperwork cannot be located and the heirs are unsure whether the item was registered upon making or during an amnesty period, it makes good sense to have an attorney contact the BATFE and determine its status. Remember, an unregistered NFA Title II weapon is completely illegal. Keeping one you find opens you to federal felony charges for which the criminal sentences can include TEN YEARS in federal prison and up to $250,000 in fines.