There is no such thing as "grand fathered" gun. The gun must have an ATF stamp that is transfered at time of sale. If the gun does not have a stamp, it is illegal. If it does not have a stamp, you can not get one. This has been true since 1933.
Violators may be fined not more than $250,000, and imprisoned not more than 10 years, or both. In addition, any vessel, vehicle or aircraft used to transport, conceal or possess an unregistered NFA firearm is subject to seizure and forfeiture, as is the weapon itself.
[49 U.S.C. 781-788, 26 U.S.C. 5861 and 5872]
Pete
