Here is the law on inheriting guns.  As always, be very careful if you plan to do this without an attorney.

13:54-1.13 Firearms passing to heirs or legatees

(a) Notwithstanding the provisions of this subchapter concerning the acquisition of a firearm, a permit to purchase a handgun or a firearms purchaser identification card shall not be required of an heir or legatee for the passing of a firearm, upon the death of its owner. A person so acquiring ownership may retain the firearm if he or she meets the requirements of N.J.A.C. 13:54-1.5 and 1.6.

(b) If an heir or legatee is not qualified to acquire a firearm, he or she may retain ownership of the firearm for the purpose of sale for a period of 180 days, which period may be extended by the chief of police or the Superintendent.

During such period the firearm must be placed in the custody of the chief of police or Superintendent.

(c) In the case of assault firearms or machine guns disposition shall be in accordance with N.J.A.C. 13:54-5.