Firearms Registration & Reporting
Serialization & Privately Made Firearms
Last updated January 5, 2026
Learn what Massachusetts law says about serialization requirements and privately made firearms, such as "ghost guns" and 3D printed guns.
Serialization
The passage of Chapter 135 of the Acts of 2024 updated Massachusetts law to now require all firearms, including frames and receivers, whether those frames or receivers are unfinished or not, to be serialized, or in other words, have a serial number applied to the frame or receiver in a permanent way. According to the law, serial numbers must, at minimum, be applied in the following way:
- Must be conspicuously engraved, cast, or otherwise permanently embedded on the frame or receiver
- Must be placed so it is not readily obliterated, altered, or removed
- Minimum depth: .003 inches
- Minimum character height (“print size”): 1/16 inch
- For non-metallic frames/receivers, serialization must be done using a metal plate permanently embedded in the material
Chapter 135 of the Acts of 2024 also directed the Department of Criminal Justice Information Services (DCJIS) to develop and maintain an electronic serial number request system. Requests for unique firearm serial numbers are now made through the MIRCS Unified Gun Portal.
Additionally, regulations under 501 CMR 20.00 set a compliance date for people who were already in possession of firearms that need serialization before the serialization laws went into effect. Individuals or entities with a previously manufactured or assembled non-exempt firearm must serialize the firearm by October 2, 2026.
Untraceable firearms
Massachusetts law now uses the term untraceable firearm to describe firearms that do not have a valid serial number, sometimes referred to as "ghost guns". An untraceable firearm is any firearm that has never been serialized, or has had its serial number removed, defaced, altered, obliterated, or mutilated.
It is unlawful to knowingly possess, purchase or receive, manufacture or assemble, sell, offer for sale, transfer, or import an untraceable firearm into the commonwealth unless it is a firearm imported or acquired by:
- New residents moving into the commonwealth or acquired by heirs or devisees through distribution of an estate and serialized within 60 days of import or acquisition
- Licensed firearms dealers, gunsmiths, distributors or manufacturers and serialized within 7 days of import or acquisition
A violation of this section is punishable by imprisonment for up to 2½ years.
Exemptions
The serialization requirements do not apply for firearms in the following cases:
- Firearms being delivered to law enforcement to be destroyed
- Firearms possessed by common carriers while performing the transport of firearms as merchandise for customers licensed to permit such transport
- Firearms possessed by nonresidents traveling through the commonwealth, provided they follow all storage and transport laws
- Firearms that are U.S. government property
- Firearms produced by licensed manufacturers and not for sale in the commonwealth
- Firearms manufactured prior to October 22, 1968
- Firearms with an existing serial number
Citations
501 CMR 20.00 - Serialization of Firearms
Privately made firearms
Massachusetts law now regulates privately made firearms (PMFs), which include firearms manufactured or assembled by an individual who is not a licensed manufacturer. The laws apply to firearms, including frames and receivers, produced through:
- Completing an unfinished frame or receiver
- CNC milling machines
- 3D printers
- Other methods where the individual manufactures or assembles the firearm themselves
A person may not manufacture or assemble a privately made firearm unless they:
- First request and receive a unique serial number from DCJIS through the MIRCS Unified Gun Portal
- Serialize the firearm during manufacture or assembly, not after completion
- Register the firearm with DCJIS within 7 days of manufacture or assembly
3D printer & CNC machine requirements
A person may not use a 3D printer or CNC milling machine to manufacture or assemble a firearm unless they hold a valid License to Carry (LTC).
It is also unlawful to sell, offer for sale, or transfer to any person in the commonwealth a 3D printer or CNC milling machine that has the primary or intended function of manufacturing or assembling firearms. According to the law, a 3D printer or CNC milling machine has the primary or intended function of manufacturing or assembling firearms if the printer or machine is "advertised, marketed or promoted to manufacture or assemble firearms, regardless of whether the printer or machine is otherwise described or classified as having other functions or as a general-purpose printer or machine." This restriction does not apply to possession by, or the sale to, federally licensed manufacturers.
Each violation of this section is punishable by imprisonment up to 1 year and/or a fine of up to $5,000 per firearm per violation.