Massachusetts Assault Weapons Ban: Exemptions and Penalties

The Massachusetts assault weapons ban prohibits possessing, selling, or transferring a broad category of firearms the state calls “assault-style firearms,” along with magazines that hold more than ten rounds. A first offense carries one to ten years in prison and a fine of $1,000 to $10,000. The 2024 reform law expanded the definitions, added second-offense penalties, brought ghost guns under the same rules, and set new registration deadlines. The ban reaches beyond rifles to certain semi-automatic pistols and shotguns, so the coverage is wider than many owners assume.

What the Ban Covers

Chapter 140, Section 121 of the General Laws defines an “assault-style firearm” two ways: by physical features, and by a list of specific models banned by name.

The Features Test

A semi-automatic centerfire rifle that accepts a detachable magazine counts as an assault-style firearm if it has at least two of these features: a folding or telescoping stock; a thumbhole stock or pistol grip; a forward grip or second handgrip; a threaded barrel designed for a flash suppressor or muzzle brake; or a barrel shroud that shields the shooter’s hand from heat.¹

Semi-automatic pistols meet the definition with two features from a parallel list, including the ability to accept a magazine outside the pistol grip, a second handgrip, a threaded barrel able to accept a suppressor, or a barrel shroud. Semi-automatic shotguns are covered with two of the following: a folding or telescoping stock, a thumbhole stock or pistol grip, a protruding forward grip, or the ability to accept a detachable magazine.¹

Named Models

Some firearms are banned by name regardless of features. The list includes all AK variants, the Colt AR-15, the UZI, the Beretta AR70, the FN/FAL family, several SWD models, the Steyr AUG, INTRATEC TEC-9 variants, and revolving-cylinder shotguns like the Street Sweeper. The state also keeps an assault-style firearm roster that can be updated, and anything added to it is banned.¹ The Executive Office of Public Safety and Security also publishes an approved firearms roster that owners and dealers should check against the current version.²

Copies and Duplicates

The law also bans any firearm that qualifies as a “copy or duplicate” of a named model. That test has two parts. The firearm must accept a detachable magazine, and either its internal functional components must be substantially similar in construction to those of a named banned weapon, or its receiver must be the same as or interchangeable with the receiver of one. A firearm sold, owned, and registered before July 20, 2016 is not treated as a copy or duplicate.¹

Large-Capacity Magazines

A “large capacity feeding device” is any fixed or detachable magazine, drum, or feed strip holding more than ten rounds, or more than five shotgun shells. Parts that could be assembled into one, if held by a single person, also count. Devices permanently altered down to the legal capacity fall outside the definition.

Penalties for a non-grandfathered large-capacity device match those for a banned firearm. Devices lawfully owned before September 13, 1994 are grandfathered, but only for narrow uses: on your own property, on private property with permission, at a licensed range or competition, at a dealer or gunsmith, or in transit between those places. In transit they must be unloaded and stored in a locked container. A grandfathered device may only be transferred to an heir, to someone outside Massachusetts, or to a licensed dealer.¹

Penalties

Possessing, selling, or transferring a banned firearm or large-capacity feeding device brings the following:

First offense: a fine of $1,000 to $10,000, imprisonment of one to ten years, or both.
Second offense: a fine of $5,000 to $15,000, imprisonment of five to fifteen years, or both.¹

The one-year mandatory minimum on a first offense means straight probation is not an option. A conviction also ends your firearms license and your ability to lawfully own firearms going forward.

Lost or Stolen Firearms

A separate penalty ladder applies if you fail to report a lost or stolen registered firearm through the state’s electronic system within seven days. A first offense carries a fine up to $1,000. A second brings up to $7,500, up to six months in jail, or both. A third or later offense carries up to $10,000, one to five years in prison, or both, and can lead to suspension or permanent revocation of your license.³

Who and What Is Exempt

Grandfathered Firearms

An assault-style firearm lawfully possessed in Massachusetts on August 1, 2024 is exempt if the owner holds a valid License to Carry and the firearm is both registered and serialized under state rules.¹ Grandfathering is not automatic. Owners who fail to register lose the protection.

Law Enforcement

Qualified active and retired law enforcement officers under the federal Law Enforcement Officers Safety Act (18 U.S.C. §§ 926B and 926C) are exempt, as are federal, state, and local law enforcement agencies. Federally licensed manufacturers are exempt only for firearms intended for sale outside Massachusetts or for export.¹

Competition Firearms

The state’s firearms oversight board must publish a roster of firearms designed solely for formal target shooting competitions or Olympic shooting events. Firearms on that roster can qualify for an exemption in sanctioned competitions.¹

Non-Resident Transport

Non-residents 18 or older may transport rifles and shotguns through Massachusetts if the firearms are not large-capacity or semi-automatic, are unloaded, and are stored in a locked container. If the firearm leaves the owner’s direct control, it must be stored in the vehicle in compliance with safe storage rules.⁴ The exception is narrow. A non-resident moving an assault-style firearm, a large-capacity rifle, or a semi-automatic shotgun through the state faces the same penalties as anyone else in possession of a banned weapon.

New Residents

Someone moving to Massachusetts with firearms has 60 days to get a Massachusetts firearms license, and must register the firearms once licensed.⁵ A firearm that qualifies as an assault-style firearm cannot be brought in and registered as a new acquisition. The grandfathering exemption only reaches guns already lawfully in Massachusetts on August 1, 2024.

Ghost Guns and Unfinished Frames

The 2024 reform expanded the definition of “firearm” to include frames, receivers, and unfinished frames or receivers. An unfinished frame or receiver is any forging, casting, 3D-printed body, or similar item that has reached a stage where it could readily be completed into a functional frame or receiver, or that is marketed for that purpose.¹

These items must be serialized and registered. The compliance deadline is October 28, 2026. Firearms manufactured before October 22, 1968 are exempt from serialization.⁵ Miss the deadline and you risk criminal liability for possessing an unregistered firearm.

Registration

Under Section 121B of Chapter 140, owners must register covered firearms with the state, providing make, model, serial number, and caliber through the electronic registration system. Any change of ownership must be reported to the Firearms Records Bureau within seven days.³

All private firearms transactions, including sales, transfers, registrations, and inheritances, run through the Massachusetts Gun Transaction Portal (the FA-10 system). The portal also handles lost or stolen reports and surrenders to a local police department. Print or save the transaction form and receipt when it appears. The system does not let you retrieve them later.⁶

Is the Ban Still in Force?

Yes. In Worman v. Healey (2019), the First Circuit upheld the law, finding that even if the banned weapons have some Second Amendment protection, the ban minimally burdens the right to bear arms and closely fits the state’s public safety interests.⁷ The Supreme Court’s 2022 decision in New York State Rifle & Pistol Association v. Bruen replaced that framework with a historical-tradition test, prompting fresh challenges to assault weapons bans nationally. Whether Worman‘s reasoning fully survives under Bruen is an open question, but as of early 2026 the Massachusetts ban continues to be enforced and no court has struck it down.

1
General Court of Massachusetts. Session Law – Acts of 2024 Chapter 135
2
Executive Office of Public Safety and Security, Massachusetts. Approved Firearms Roster – February 2025
3
Mass.gov. Mass General Laws c.140 Section 121B
4
General Court of Massachusetts. Massachusetts General Laws Chapter 140 Section 129C
5
The Commonwealth of Massachusetts Executive Office of Public Safety and Security. An Act Modernizing Firearm Laws – Guidance #4
6
Mass.gov. Record a Private Firearms Sale or Registration
7
Justia. Worman v. Healey, No. 18-1545 (1st Cir. 2019)