CHAPTER 3. Assembly of Firearms [29180. - 29186.]

Cal. Penal Code - PEN 3.

in effect

Cal. Penal Code - PEN § 29180. Section 29180.

(a) For purposes of this chapter, “manufacturing” or “assembling” a firearm means to fabricate or construct a firearm, including through additive, subtractive, or other processes, or to fit together the component parts of a firearm to construct a firearm. (b) Before manufacturing or assembling a firearm, a person manufacturing or assembling the firearm shall, for any firearm that does not have a valid state or federal serial number or mark of identification imprinted on the frame or receiver, do all of the following: (1) (A) Apply to the Department of Justice for a unique serial number or other mark of identification pursuant to Section 29182. (B) Each application shall contain a description of the firearm that the applicant intends to assemble, the applicant’s full name, address, date of birth, and any other information that the department may deem appropriate. (2) (A) Within 10 days of manufacturing or assembling a firearm in accordance with paragraph (1), the unique serial number or other mark of identification provided by the department shall be engraved or permanently affixed to the firearm in a manner that meets or exceeds the requirements imposed on licensed importers and licensed manufacturers of firearms pursuant to subsection (i) of Section 923 of Title 18 of the United States Code and regulations issued pursuant thereto. (B) If the firearm is manufactured or assembled from polymer plastic, 3.7 ounces of material type 17-4 PH stainless steel shall be embedded within the plastic upon fabrication or construction with the unique serial number engraved or otherwise permanently affixed in a manner that meets or exceeds the requirements imposed on licensed importers and licensed manufacturers of firearms pursuant to subsection (i) of Section 923 of Title 18 of the United States Code and regulations issued pursuant thereto. (3) After the serial number provided by the department is engraved or otherwise permanently affixed to the firearm, the person shall notify the department of that fact in a manner and within a time period specified by the department, and with sufficient information to identify the owner of the firearm, the unique serial number or mark of identification provided by the department, and the firearm in a manner prescribed by the department. (c) Any person who owns a firearm or firearm precursor part that does not bear a valid state or federal serial number or mark of identification shall be deemed to be in compliance with subdivision (b) of Section 23920 if they comply with all of the following: (1) (A) By no later than January 1, 2024, or if a new resident of the state, within 60 days after arriving in the state with a firearm that does not have a valid state or federal serial number or mark of identification, apply to the Department of Justice for a unique serial number or other mark of identification pursuant to Section 29182. (B) An application to the department for a serial number or mark of identification for a firearm precursor part shall include, in a manner prescribed by the department, information identifying the applicant and a description of the firearm that the applicant intends to manufacture or assemble with the firearm precursor part, and any other information that the department may deem appropriate. (2) Within 10 days of receiving a unique serial number or other mark of identification from the department, engrave or permanently affix that serial number or mark of identification to the firearm in accordance with regulations prescribed by the department pursuant to Section 29182 and in a manner that meets or exceeds the requirements imposed on licensed importers and licensed manufacturers of firearms pursuant to subsection (i) of Section 923 of Title 18 of the United States Code and regulations issued pursuant thereto. If the firearm is manufactured or assembled from polymer plastic, 3.7 ounces of material type 17-4 PH stainless steel shall be embedded within the plastic upon fabrication or construction. (3) After the serial number provided by the department is engraved or otherwise permanently affixed to the firearm, notify the department of that fact in a manner and within a time period specified by the department and with sufficient information to identify the owner of the firearm, the unique serial number or mark of identification provided by the department, and the firearm in a manner prescribed by the department. (d) (1) Except by operation of law, a person, corporation, or firm that is not a federally licensed firearms manufacturer shall not sell or transfer ownership of a firearm, as defined in subdivision (g) of Section 16520, if any of the following are true: (A) That person, corporation, or firm manufactured or assembled the firearm. (B) That person, corporation, or firm knowingly caused the firearm to be manufactured or assembled by a person, corporation, or firm that is not a federally licensed firearms manufacturer. (C) That person, corporation, or firm is aware that the firearm was manufactured or assembled by a person, corporation, or firm that is not a federally licensed firearms manufacturer. (2) Paragraph (1) does not apply to the transfer, surrender, or sale of a firearm to a law enforcement agency. (3) Any firearms confiscated by law enforcement that do not bear an engraved serial number or other mark of identification pursuant to subdivision (b) or (c), or a firearm surrendered, transferred, or sold to a law enforcement agency pursuant to paragraph (2) shall be destroyed as provided in Section 18005. (4) Sections 26500 and 27545, and subdivision (a) of Section 31615, do not apply to the transfer, sale, or surrender of firearms to a law enforcement agency pursuant to paragraph (2). (e) A person, corporation, or firm shall not knowingly allow, facilitate, aid, or abet the manufacture or assembling of a firearm by a person who is within any of the classes identified by Chapter 2 (commencing with Section 29800) or Chapter 3 (commencing with Section 29900) of Division 9 of this code, or Section 8100 or 8103 of the Welfare and Institutions Code. (f) A person, corporation, or firm shall not knowingly manufacture or assemble, or knowingly cause, allow, facilitate, aid, or abet the manufacture or assembling of, a firearm that is not imprinted with a valid state or federal serial number or mark of identification. (g) If the firearm is a handgun, a violation of this section is punishable by imprisonment in a county jail not to exceed one year, or by a fine not to exceed one thousand dollars ($1,000), or by both that fine and imprisonment. For all other firearms, a violation of this section is punishable by imprisonment in a county jail not to exceed six months, or by a fine not to exceed one thousand dollars ($1,000), or by both that fine and imprisonment. Each firearm found to be in violation of this section constitutes a distinct and separate offense. This section does not preclude prosecution under any other law providing for a greater penalty.

Cal. Penal Code - PEN § 29182. Section 29182.

(a) The Department of Justice may accept applications from, and may grant applications in the form of serial numbers pursuant to Sections 23910 and 29180 to, persons who wish to own a firearm or firearm precursor part that does not have a valid state or federal serial number or mark of identification. (b) An application made pursuant to subdivision (a) shall only be granted by the department if the applicant does all of the following: (1) For each transaction, completes a firearms eligibility check pursuant to Section 28220 demonstrating that the applicant is not prohibited by state or federal law from possessing, receiving, owning, or purchasing a firearm. (2) Presents proof of age and identity as specified in Section 16400 demonstrating that person is 21 years of age or older. (3) Provides a description of the firearm that the applicant owns or intends to manufacture or assemble, in a manner prescribed by the department. (4) Has a valid firearm safety certificate. (c) The department shall inform applicants who are denied an application of the reasons for the denial in writing. The reason for denial may include, without limitation, any of the following: (1) Based on a firearm eligibility check conducted pursuant to Section 28220, the department has determined that the applicant is prohibited by state or federal law from possessing, receiving, owning, or purchasing a firearm. (2) Based on a firearm eligibility check conducted pursuant to Section 28220, the department is unable to ascertain the disposition of an arrest or criminal charge, is unable to ascertain the outcome of a mental health evaluation or treatment, or otherwise is unable to conclusively determine that the applicant is not ineligible. (3) The applicant’s description of the firearm that the applicant owns or intends to manufacture or assemble indicates that the firearm would be considered any of the following: (A) An unsafe handgun. (B) An assault weapon, as defined in Section 30510 or 30515. (C) A machinegun. (D) A .50 BMG rifle. (E) A destructive device, as defined in Section 16460. (F) A short-barreled rifle or short-barreled shotgun. (G) An unconventional pistol. (H) Any other firearm prohibited by this part. (d) (1) All applications received on or after January 1, 2024, shall be granted or denied within 90 calendar days after the receipt of the application by the department. (2) Any application received before January 1, 2024, may be granted or denied within a period of time prescribed by the department. (e) (1) This chapter does not authorize a person to manufacture, assemble, or possess a weapon prohibited under Section 16590, an assault weapon as defined in Section 30510 or 30515, a machinegun as defined in Section 16880, a .50 BMG rifle as defined in Section 30530, or a destructive device as defined in Section 16460. (2) This chapter does not authorize a person to manufacture or assemble an unsafe handgun, as defined in Section 31910. (f) The department shall adopt regulations to administer this chapter.

Cal. Penal Code - PEN § 29183. Section 29183.

The Department of Justice may charge an applicant a fee for each distinguishing number or mark it issues in an amount sufficient to reimburse it for the actual costs associated with assigning a distinguishing number or mark to a firearm pursuant to Sections 29180 and 29182 and for conducting a firearms eligibility check pursuant to paragraph (1) of subdivision (b) of Section 29182. All money received pursuant to this section shall be deposited in the Dealers’ Record of Sale Special Account of the General Fund, to be available upon appropriation by the Legislature.

Cal. Penal Code - PEN § 29184. Section 29184.

The Department of Justice shall maintain and make available upon request information concerning both of the following: (a) The number of serial numbers issued pursuant to Section 29182. (b) The number of arrests for violations of Section 29180.

Cal. Penal Code - PEN § 29185. Section 29185.

(a) No person, other than a state-licensed firearms manufacturer, shall use a computer numerical control (CNC) milling machine or three-dimensional printer to manufacture a firearm. (b) It is unlawful to sell, offer to sell, or transfer a CNC milling machine or three-dimensional printer that has the sole or primary function of manufacturing firearms to any person in this state, other than a state-licensed firearms manufacturer. (c) It is unlawful for any person in this state other than a state-licensed firearms manufacturer to possess, purchase, or receive a CNC milling machine or three-dimensional printer that has the sole or primary function of manufacturing firearms. (d) Subdivisions (b) and (c) do not apply to any of the following: (1) A person who is engaged in the business of selling manufacturing equipment to a state-licensed firearms manufacturer, and who possesses a CNC milling machine or three-dimensional printer with the intent to sell or transfer the CNC milling machine or three-dimensional printer to a state licensed firearms manufacturer. (2) A common carrier licensed under state law, or a motor carrier, air carrier or carrier affiliated with an air carrier through common controlling interest that is subject to Title 49 of the United States Code, or an authorized agent of any such carrier, when acting in the course and scope of duties incident to the receipt, processing, transportation, or delivery of property. (3) A person who, before June 30, 2022, possessed a CNC milling machine that has the sole or primary function of manufacturing firearms and who, within 90 days after that date, does one of the following: (A) Sells or transfers the machine to a federally licensed firearms manufacturer or importer. (B) Sells or transfers the machine to a person described in paragraph (1). (C) Removes the machine from this state. (D) Relinquished the machine to a law enforcement agency. (E) Otherwise lawfully terminates possession of the machine. (4) A person who, before July 1, 2024, possessed a three-dimensional printer that has the sole or primary function of manufacturing firearms and who, within 90 days after that date, does one of the following: (A) Sells or transfers the machine to a state-licensed firearms manufacturer. (B) Sells or transfers the machine to a person described in paragraph (1). (C) Removes the machine from this state. (D) Relinquishes the machine to a law enforcement agency. (E) Otherwise lawfully terminates possession of the machine. (e) This section does not apply to any member of the Armed Forces of the United States or the National Guard, while on duty and acting within the scope and course of employment, or any law enforcement agency or forensic laboratory. (f) A violation of this section is punishable as a misdemeanor. (g) As used in this section, the following terms are defined as follows: (1) “State-licensed firearms manufacturer” has the same meaning as the term “licensee” is defined in Section 29030. (2) “Three-dimensional printer” means a computer-aided manufacturing device capable of producing a three-dimensional object from a three-dimensional digital model through an additive manufacturing process that involves the layering of two-dimensional cross sections formed of a resin or similar material that are fused together to form a three-dimensional object.

Cal. Penal Code - PEN § 29186. Section 29186.

(a) It is unlawful to knowingly or willfully cause another person to engage in the unlawful manufacture of firearms, or to knowingly or willfully aid, abet, promote, or facilitate the unlawful manufacture of firearms. (b) For the purposes of this section, the “unlawful manufacture of firearms” includes any of the following: (1) The manufacture of a firearm by a minor, or by a person who is prohibited from owning or possessing firearms under California law. (2) The manufacture of four or more firearms within the state in the same calendar year by an individual who is not licensed to manufacture firearms pursuant to California law, in violation of Section 29010. (3) The manufacture of any firearm using a three-dimensional printer or computer numerical control (CNC) milling machine by an individual who is not licensed to manufacture firearms pursuant to California law, in violation of Section 29185. (4) The manufacture of a firearm by a person who is not a federally licensed firearms manufacturer, for the purpose of selling or transferring ownership of that firearm to another person who is not a federally licensed firearms manufacturer, in violation of subdivision (d) of Section 29180. (5) The manufacture of a firearm for the purpose of selling, loaning, or transferring the firearm to another person, with the intent to complete the sale, loan, or transfer without a required background check on the transferee initiated by a licensed firearms dealer, in violation of Section 27520. (6) The manufacture of any of the following: (A) Assault weapons or .50 BMG rifles, in violation of Section 30600. (B) Firearms that are not immediately recognizable as firearms, in violation of Section 24510. (C) Firearms that are not imprinted with a valid state or federal serial number or mark of identification, in violation of subdivision (f) of Section 29180. (D) Large-capacity magazines or large-capacity magazine conversion kits, in violation of Section 32310 or 32311. (E) Machineguns, in violation of Section 32625. (F) Multiburst trigger activators, in violation of Section 32900. (G) Short-barreled rifles or short-barreled shotguns, in violation of Section 33215. (H) Undetectable firearms, in violation of Section 24610. (I) Unsafe handguns, in violation of Section 32000. (J) Zip guns, in violation of Section 33600. (K) Any other weapon defined as a “generally prohibited weapon” under Section 16590. (c) A violation of this section is a misdemeanor.

Source: CA Legislative Counsel Bulk DataURL: https://downloads.leginfo.legislature.ca.gov/pubinfo_2025.zipFetched: 6/27/2026