California Penal Code Section 29180 [1] requires that any person who manufactures or assembles a firearm must apply to the California Department of Justice for a unique serial number or other mark of identification before completing the manufacturing or assembly process. California was the first state to enact this type of requirement, beginning with AB 857 in 2016. Since then, the legislature has significantly expanded the regulatory framework surrounding ghost guns and their component parts.
Application Process
Before manufacturing or assembling a firearm, the person must:
- Apply to the DOJ through the California Firearms Application Reporting System (CFARS) [2]
- Provide personal identifying information and undergo a background check
- Describe the type of firearm to be manufactured (handgun, rifle, or shotgun)
- Receive a unique serial number assigned by the DOJ
- Engrave or permanently affix the assigned serial number on the firearm in a manner prescribed by regulation
Engraving Requirements
The serial number must be engraved or permanently affixed on the firearm in compliance with specific technical standards:
- The serial number must be placed on the frame or receiver
- Characters must be at least 1/16 inch deep and 1/16 inch high
- The engraving must be in a conspicuous location on the firearm
- The serial number must not be susceptible to being readily obliterated, altered, or removed
Prohibition on Transfer
A self-manufactured firearm may not be sold or transferred to any other person. Under Penal Code Section 29180(d) [3], a person who manufactures or assembles a firearm for personal use may not sell, offer for sale, assign, pledge, lease, give, lend, or otherwise transfer that firearm without first having a licensed manufacturer apply a licensed manufacturer's serial number to the weapon and process the transfer through a licensed dealer.
AB 1263: Expanded Accessories and Ghost Gun Regulation (Effective January 1, 2026)
AB 1263 [4] significantly expanded the regulation of firearm accessories and ghost gun components. The law broadens the definition of "firearm accessories" under the Firearm Industry Responsibility Act (FIRA) to include parts commonly used to produce ghost guns, assault weapons, and machine guns. These newly regulated accessories include pistol grips, thumbhole stocks, folding or telescoping stocks, flash suppressors, forward pistol grips, threaded handgun barrels, second handgrips, and handgun shrouds.
Key requirements under AB 1263 include:
- Age verification and ID matching: All firearm parts shipments to California residents require age verification and identification matching at the point of delivery
- Adult signature required: An adult signature is required for delivery of all firearm accessories
- Prohibition on digital manufacturing files: AB 1263 prohibits the distribution of CAD, CNC, or 3D printer files that can be used to produce firearms, firearm accessories, barrels, or large-capacity magazines
- Expanded civil liability: The law extends civil liability under FIRA to cover the newly defined accessory categories
The California Attorney General released an informational bulletin [5] outlining compliance obligations for retailers and distributors.
SB 704: Firearm Barrel Sales Through Dealers (Effective January 1, 2026)
SB 704 [6] adds a new layer of regulation targeting standalone firearm barrel sales, recognizing that barrels are a critical component in ghost gun manufacturing. The law defines "firearm barrel" broadly to include partially finished barrels that can be "readily completed."
SB 704 has a two-phase implementation:
- Phase 1 (January 1, 2026): All standalone firearm barrel sales must be conducted in person through a licensed FFL. Barrels may no longer be shipped directly to California residents. Violations are misdemeanors.
- Phase 2 (July 1, 2027): Adds a DOJ background check and electronic reporting requirement for all barrel transactions. The DOJ-prescribed eligibility check fee is capped at $5 per transaction.
Federal Law: Bondi v. VanDerStok (March 2025)
On March 26, 2025, the U.S. Supreme Court issued a 7-2 decision in Bondi v. VanDerStok [7] (originally styled Garland v. VanDerStok), upholding the ATF's 2022 final rule classifying weapons parts kits and unfinished frames and receivers as "firearms" under the Gun Control Act of 1968. Justice Gorsuch wrote for the majority, concluding that at least some weapons parts kits fall within the statutory definition of "firearm" and that the ATF rule is a permissible interpretation of the statute.
The decision reinforces the federal serialization requirements for commercially produced frames, receivers, and parts kits. California's state-level requirements under Section 29180 are broader than the federal rule because they apply to personally manufactured firearms regardless of how the frame or receiver was acquired, and they require prior DOJ approval before manufacturing begins.
Penalties
Violation of Section 29180 is a misdemeanor. Manufacturing or assembling a firearm without first obtaining a serial number from the DOJ is punishable by imprisonment in a county jail for up to one year, a fine of up to $1,000, or both. Possession of an unserialized firearm manufactured after the effective date may also result in charges under other provisions of the Penal Code, including Sections 23920 and 23925 [8], which prohibit possession and sale of firearms lacking identification marks.