Boston Assault Weapons Act:
Registration and License

The City of Boston has enacted municipal ordinances that impose additional requirements on firearms owners beyond those established by state law. Boston is also subject to a ban on the sale and possession of assault weapons and large capacity magazines that the state legislature enacted for the city as Chapter 596 of the Acts of 1989. At the state level, assault-style firearms and large capacity feeding devices are addressed under MGL Chapter 140, Section 131M^[1].

Boston's 1989 Assault Weapons Act

Chapter 596 of the Acts of 1989 did require owners of assault weapons already lawfully held, who also held a firearm identification card for them, to apply for a city license to possess them. Under Chapter 596 of the Acts of 1989 ("An Act relative to assault weapons in the city of Boston," approved December 9, 1989)^[2], the act makes it unlawful in the city of Boston to sell, rent, lease, possess, purchase, barter, display, or transfer an assault weapon, a large capacity magazine or a large capacity ammunition belt, and it establishes a seven-member assault weapon roster board chaired by the police commissioner. The roster board compiles and publishes an assault weapon roster, and the prohibition of a weapon placed on the roster takes effect when it is included in the next publication of the roster. Section 6 of the act required any person lawfully in possession of an assault weapon and a firearm identification card for it to apply, within ninety days of the act taking effect, to the police commissioner for a license to possess that assault weapon. The license allows the licensee to keep the assault weapon in his residence. A person denied the license had ninety days to dispose of the weapon, and a person who obtained an assault weapon registered under the act by bequest or intestate succession had ninety days to apply for a license or dispose of it.

Under the post-Chapter 135 framework, state-level registration is handled through the Section 121B electronic system (MIRCS Unified Gun Portal). A firearm already recorded on an FA-10 form from a dealer sale, personal registration, or transfer counts as registered, and EOPSS guidance states that individuals are not required to comply with the new registration and serialization requirements until October 28, 2026. The 1989 act adds a city license to possess for assault weapons that were lawfully held when it took effect, and the act refers to such a weapon as registered under the act. The act does not say how the city administers that license today.

Impact of Chapter 135

Chapter 135 of the Acts of 2024 restructured the state-level assault weapons ban so that Section 131M contains both the prohibition (subsection a) and the grandfathering framework (subsections b and c). 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 and a person who sells, rents, leases or otherwise transfers a firearm without being licensed under Section 122 or exempt under Section 129C. The 1989 act makes it unlawful in the city of Boston to possess an assault weapon as the act defines it, and the exceptions in section 3 of the act do not include firearms grandfathered under Section 131M. The 1989 act uses its own definition of "assault weapon" in section 1 and its own roster, separate from the state definition of "assault-style firearm" that Chapter 135 added to Section 121.

Other Boston-Specific Regulations

• Additional restrictions on the discharge of firearms within city limits

Enforcement

A first violation of Chapter 596 of the Acts of 1989 as to an assault weapon is punishable by a fine of $1,000, and a subsequent offense by imprisonment for not more than two and one-half years. A violation as to a magazine or ammunition belt is punishable by a fine of $200 for a first offense and $500 for a subsequent offense. The Boston police commissioner may revoke licenses under sections 122 and 131 of chapter 140 for a violation of the act.