Chapter 135 of the Acts of 2024:
An Act Modernizing Firearm Laws

Chapter 135 of the Acts of 2024^[1], titled "An Act Modernizing Firearm Laws," was signed by Governor Maura Healey on July 25, 2024, and took effect on October 2, 2024. It is the most comprehensive overhaul of Massachusetts firearms law since Chapter 180 of the Acts of 1998.

What Changed

Chapter 135 touches nearly every section of the firearms code. The major changes include:

• Assault weapons ban restructure: Chapter 135 restructured the former assault weapons ban. Section 131M(a) now contains the primary prohibition on assault-style firearms and large capacity feeding devices not grandfathered under subsections (b) and (c). Untraceable firearms are prohibited by Section 121C and covert firearms by Section 131N. Section 131M(b) and (c) provide the grandfathering framework. Section 40 of the act rewrote the first paragraph of Section 128, which penalizes a licensed dealer who sells or furnishes a firearm or ammunition to a person without a license, card or permit, subject to the Section 131A permit-to-purchase exception, and an unlicensed person not exempt under Section 129C who sells, rents, leases or otherwise transfers a firearm.
• LTC class elimination: Chapter 284 of 2014 eliminated the Class B LTC. Chapter 135 removed remaining class designation references, formalizing the single-class License to Carry.
• Untraceable firearm prohibitions: New Section 121C created comprehensive requirements for firearm serialization, and new Section 121D regulated the use of 3D printers and CNC milling machines to manufacture or assemble firearms. The statute uses “untraceable firearm” and “privately made firearm” as the defined terms; “ghost gun” is the commonly used name.
• Extreme Risk Protection Orders: Sections 131R through 131Y, originally created by Chapter 123 of 2018, were expanded to remove the requirement that the respondent hold an active firearms license and to broaden who may petition for an order.
• Firearms dashboards: New public data reporting requirements for the state.
• Prohibited areas: Created a new list of locations where firearms may not be carried under Section 10(k): government administrative, judicial, and correctional buildings, grounds, and parking areas (a municipality may vote to exclude its administrative buildings, and state-owned public land open to hunting is not covered), and ballot-storage, tabulation, polling, and early voting locations. Hospitals and places of worship are not included.
• Tiered storage requirements: Updated Section 131L's storage rule, subject to its exemption for certain antique firearms and replicas, with higher penalties for large capacity or semiautomatic firearms and machine guns. Penalties may be higher where a person younger than 18 may have access without committing an unforeseeable trespass, with subsection (c) limited to minors who do not hold a valid firearm identification card.

Effective Dates

The law took effect on October 2, 2024. Certain provisions have phased implementation dates. Section 158 of the act requires that all firearms be serialized not later than 1 year after the serial number request system under Section 121C is completed and publicly available, and EOPSS Guidance #5 states that individuals are not required to comply with the registration and serialization requirements of Sections 121B and 121C until October 28, 2026. The Firearm Licensing Review Board under Section 130B was originally established by Chapter 150 of the Acts of 2004.

Referendum Timeline

A referendum on Chapter 135, designated Question 9 ("Firearms Regulation"), is on the November 3, 2026 ballot^[2]. A No vote on Question 9 would repeal the law, and a Yes vote would keep it in place. Under the Massachusetts Constitution, the law is repealed if it is not approved by a majority of voters voting on the question and the No votes are at least 30 percent of the total ballots cast at the election, and the repeal takes effect 30 days after the election. Until a referendum repeal takes effect, the law remains in force, subject to its phased implementation dates. The referendum creates legal uncertainty for individuals and businesses making long-term compliance investments.

Cross-References

Chapter 135 amendments are integrated throughout the statutory entries on this site. Individual section entries cover the specific changes in detail:

• Section 131 (LTC): Single-class license, suitability standard, Licensing Review Board
• Section 131M: Assault-style firearm prohibition (subsection a) and grandfathering (subsections b and c)
• Section 128: Dealer and unlicensed sale violations (first paragraph rewritten by section 40)
• Sections 121C and 121D: Untraceable firearms and serialization
• Sections 131R through 131Y: Extreme Risk Protection Orders
• Section 131L: Updated storage requirements

Registration and Serialization Timeline

The MIRCS Unified Gun Portal is now the online registration and serialization service. EOPSS Guidance #5, dated September 18, 2026, consolidates the answers in Guidance #1 through #4 and states that individuals are not required to comply with the registration and serialization requirements of Sections 121B and 121C until October 28, 2026.