MGL Chapter 140, Sections 128 and 131M:
Dealer Licensing Violations and the Assault-Style Firearm Ban

Massachusetts General Laws Chapter 140, Section 131M(a) ^[1] contains the prohibition on assault-style firearms in the Commonwealth. Chapter 135 of the Acts of 2024 ^[2] restructured the former assault weapons ban, with Section 131M(a) prohibiting any person from possessing, owning, offering for sale, selling or otherwise transferring in the commonwealth or importing into the commonwealth an assault-style firearm or a large capacity feeding device, Section 128 covering dealer licensing violations, and Section 131M(b) exempting an assault-style firearm lawfully possessed within the commonwealth on August 1, 2024 by an owner with a license to carry or a holder of a license to sell, provided that the firearm is registered under Section 121B and serialized under Section 121C.

New Terminology: "Assault-Style Firearm"

Chapter 135 struck out the definition of "assault weapon" in Section 121 and inserted a definition of "assault-style firearm" in its place. The current Section 121 definition uses feature tests, an assault-style firearm roster, a retained named-model list, and a copy-or-duplicate clause.^[3]

Prohibited Items

Chapter 135 prohibits the following items, each under its own section of Chapter 140:

Assault-style firearms as defined in Section 121, prohibited under Section 131M(a)

Untraceable firearms (ghost guns): a firearm that has not been serialized, or whose serial or other identification number has been removed, defaced, altered, obliterated or mutilated in any manner, prohibited under Section 121C (not Section 131M(a))Covert and undetectable firearms: covert firearms (camouflaged, or shaped so that they do not resemble or are not immediately recognizable as firearms) and undetectable firearms (a firearm that, after removal of grips, stocks and magazines, is not detectable by walk-through metal detectors calibrated and operated to detect the federal security exemplar, or a major component that does not produce an image accurately depicting its shape under detection devices commonly used at secure public buildings and transit stations), prohibited under Section 131N (not Section 131M(a))Large capacity feeding devices as defined in Section 121, prohibited under Section 131M(a), with Section 131M(c) grandfathering for devices lawfully possessed on September 13, 1994 only if such possession is on private property owned or legally controlled by the person in possession, on private property that is not open to the public with the express permission of the property owner or the property owner's authorized agent, on the premises of a licensed firearms dealer or gunsmith for the purpose of lawful repair, at a licensed firing range or sports shooting competition venue, or while traveling to and from these locations, and only if the device is stored unloaded and secured in a locked container

Current Constitutional Litigation

Capen and Hanlon: The First Circuit's April 2025 Capen decision affirmed the denial of a preliminary injunction. It was not a final merits judgment. The later Hanlon case was consolidated into the lead Capen district-court docket, and that proceeding was stayed by an order entered July 9, 2026 granting a joint motion to stay.^[10]

Recchia v. Campbell: The First Circuit affirmed dismissal of a facial challenge under controlling circuit precedent.^[8] The panel treated the magazine argument as unpreserved and undeveloped and did not decide other arguments that had not been raised.

Third Circuit disagreement: In 2026, the en banc Third Circuit reached a contrary Second Amendment result concerning New Jersey's assault-firearm and over-10-round magazine restrictions.^[9] That ruling is not binding in Massachusetts or in the First Circuit, but it documents an active disagreement among federal appellate courts.

Penalties

Violation of Section 128 (dealer licensing violations) is punishable by a fine of not less than $1,000 nor more than $10,000, by imprisonment in state prison for not more than 10 years or in a house of correction for not more than 2.5 years, or by both fine and imprisonment. That penalty applies to a person licensed under Section 122 or 122B who sells or furnishes a firearm or ammunition to any person without a firearm license card or permit, and it carries no mandatory minimum prison term, although the fine has a $1,000 floor and the dealer's license is revoked with no reapplication for 10 years. Section 128 separately punishes selling, renting, leasing, or transferring a firearm without being licensed under Section 122 or exempt under Section 129C, or engaging in business as a gunsmith without that license or exemption, by a fine of $1,000 to $10,000, imprisonment of not less than 1 year nor more than 10 years, or both, so a fine alone is possible and there is no mandatory prison term. The assault-style firearms penalty is in Section 131M(d): a first offense carries a fine of $1,000 to $10,000, imprisonment of 1 to 10 years, or both, and a second offense a fine of $5,000 to $15,000, imprisonment of 5 to 15 years, or both.

For grandfathering provisions applicable to lawfully possessed pre-ban assault-style firearms and large capacity feeding devices, see Section 131M.

See also: Section 131M: Grandfathering Assault-Style Firearms (Massachusetts)

See also: Chapter 135 of the Acts of 2024: What Changed

See also: Is My Rifle Legal in Massachusetts? A Compliance Guide