Cal. Penal Code § 17710

(a) The provisions listed in Section 16590 do not apply to “any other weapon” as defined in subsection (e) of Section 5845 of Title 26 of the United States Code, which is in the possession of a person permitted to possess the weapons under the federal Gun Control Act of 1968 (Public Law 90-618), as amended, and the regulations issued pursuant thereto. (b) Any person prohibited by Chapter 1 (commencing with Section 29610), Chapter 2 (commencing with Section 29800), or Chapter 3 (commencing with Section 29900) of Division 9 of Title 4 of this part, or Section 8100 or 8103 of the Welfare and Institutions Code, from possessing these weapons who obtains title to these weapons by bequest or intestate succession may retain title for not more than one year, but actual possession of these weapons at any time is punishable under Chapter 1 (commencing with Section 29610), Chapter 2 (commencing with Section 29800), or Chapter 3 (commencing with Section 29900) of Division 9 of Title 4 of this part, or Section 8100 or 8103 of the Welfare and Institutions Code. Within the year, the person shall transfer title to the weapons by sale, gift, or other disposition. Any person who violates this section is in violation of the applicable provision listed in Section 16590. (c) The exemption provided by this section does not apply to a pen gun.