Massachusetts Gun Ban: Prohibited Firearms, Penalties, and Storage

Massachusetts prohibited firearms fall into a handful of clearly defined categories: assault-style rifles, pistols, and shotguns that meet the state’s feature test or appear on its named-model list; magazines and other feeding devices that hold more than ten rounds (or more than five shotgun shells); silencers; bump stocks and trigger cranks; and, since 2024, any privately made firearm without a state-issued serial number. Possession of any of these, outside a narrow grandfather exception, is a felony carrying years of state prison time.

Assault-Style Firearms

The 2024 Act Modernizing Firearm Laws replaced the older term “assault weapon” with “assault-style firearm” and rewrote the definition. A semiautomatic centerfire rifle qualifies as an assault-style firearm if it accepts a detachable magazine and has at least two of the following features: a folding or telescoping stock, a thumbhole stock or pistol grip, a forward grip, a threaded barrel designed for a flash suppressor, or a barrel shroud. Semiautomatic pistols and semiautomatic shotguns have their own two-feature tests.¹

The statute also bans specific models by name regardless of features. The list includes the AK (all models), the Colt AR-15, the UZI, the Beretta AR70, and others, along with copies or duplicates of those firearms. A rifle that would pass the feature test can still be illegal if it is a copy of a named model.¹

Large Capacity Feeding Devices

Any magazine, drum, belt, or similar device that holds more than 10 rounds of ammunition is a large capacity feeding device under Massachusetts law. For shotguns, the limit is 5 shells. Selling, transferring, or possessing one of these devices is illegal unless it was lawfully owned before September 13, 1994.¹²

Note the shotgun distinction. The 5-round cap applies only to shotgun shells. A handgun magazine holding more than 10 rounds is subject to the same ban as a rifle magazine of that capacity, not the lower shotgun number. This trips up people who assume pistol magazines are treated differently from rifle magazines.

Silencers, Bump Stocks, and Trigger Cranks

Sound suppressors, commonly called silencers, are illegal to possess in Massachusetts. The state also classifies bump stocks and trigger cranks as machine guns, which puts them in the strictest firearm category the state recognizes.¹

A bump stock is defined as any device that uses a weapon’s recoil energy to generate reciprocating action that facilitates repeated trigger activation. A trigger crank attaches to the trigger guard and allows rapid successive trigger pulls through a hand-cranked mechanism. Possessing either carries the same penalties as possessing a machine gun.

Ghost Guns and Unserialized Firearms

The 2024 law extended firearm regulation to privately made guns and the parts used to build them. The statutory definition of “firearm” now includes unfinished frames and receivers. An unfinished frame or receiver is any forging, casting, 3D-printed body, or similar item that has reached a stage where it can be readily completed to function as a firearm frame, or that is marketed for that purpose.³

Anyone who manufactures or assembles a privately made firearm must obtain a unique serial number from the Department of Criminal Justice Information Services before beginning manufacture or assembly, then engrave or permanently embed that number conspicuously on the frame or receiver during production. A homemade firearm without a state-issued serial number is contraband regardless of how well it functions or who built it.³

Penalties

Massachusetts stacks its firearm penalties in two overlapping tracks. Chapter 140, Section 131M covers the possession of banned items themselves. Chapter 269, Section 10 covers the possession of certain firearms without a license. A single incident can trigger both.

Banned Weapons and Feeding Devices

Possessing an assault-style firearm or large capacity feeding device that was not lawfully owned before September 13, 1994 carries a first-offense penalty of 1 to 10 years in state prison, a fine of $1,000 to $10,000, or both. A second offense raises the range to 5 to 15 years in prison and $5,000 to $15,000 in fines, or both.²

Large Capacity Firearms Without a License

Knowingly possessing a large capacity firearm or feeding device without a valid License to Carry is charged separately under Chapter 269 and carries 2.5 to 10 years in state prison. That minimum generally cannot be suspended or reduced. If the defendant holds a valid Firearm Identification Card, the mandatory minimum does not apply, though criminal charges still follow.⁴

The Pre-1994 Grandfather Exception

The main way a Massachusetts resident lawfully possesses an assault-style firearm or a large capacity magazine today is by proving ownership before September 13, 1994, the date the federal assault weapons ban took effect. Massachusetts pegged its own grandfathering provision to that date. Weapons and feeding devices lawfully possessed before the cutoff remain legal in the owner’s hands.²

Documentation is decisive. Purchase receipts, registration records, and sworn affidavits establishing a timeline of ownership are what turn a possession charge into a dismissed case. Without proof of pre-ban ownership, the burden of an otherwise lawful item shifts against the owner in court.

Where Even Legal Firearms Cannot Go

Owning a firearm lawfully in Massachusetts does not mean you can carry it everywhere. Two categories of location are off-limits even to LTC holders.

Schools have long been restricted. Carrying any firearm, loaded or unloaded, on the grounds of any elementary school, secondary school, college, or university without written authorization from the institution’s board or officer in charge is punishable by a fine up to $1,000, up to two years in jail, or both.⁴

The 2024 law added a second category of “prohibited areas”: any building, grounds, or parking area owned or controlled by state, county, or municipal government and used for government administration, court proceedings, or correctional services. Polling places and early voting sites are prohibited areas during voting and ballot-tabulation hours, including the area within 150 feet of the entrance. A municipality can vote to exempt its own administrative buildings, but the default is no firearms allowed. Violating the prohibited-area rule carries a fine up to $1,000, up to two and a half years in a house of correction, or both.⁵

Storage Rules That Turn Legal Ownership Into a Crime

A firearm you are legally allowed to own can still put you in court if you store it wrong. Massachusetts requires every firearm to be kept in a locked container or equipped with a tamper-resistant mechanical lock that renders it inoperable to anyone other than the owner or an authorized user. A firearm you are actively carrying or that is under your direct control does not need to be locked. Antique firearms manufactured in or before 1899, and replicas of those firearms that do not use modern ammunition, are exempt.⁶

Penalties escalate with the type of firearm and whether a minor could reach it. Standard firearm stored improperly: $1,000 to $7,500 fine and up to 18 months of imprisonment. Large capacity or semiautomatic firearm stored improperly: $2,000 to $15,000 fine and 18 months to 12 years. If a minor under 18 could access an improperly stored large capacity firearm, the range jumps to $10,000 to $20,000 and 4 to 15 years.⁶

Reporting a Lost or Stolen Firearm

If a firearm you own is lost or stolen, you have 7 days to report it through the state’s electronic firearms registration system. The report must include make, model, serial number, caliber, and whether the firearm is a large capacity firearm. The system notifies the licensing authority in both the city where you live and the city where your license was issued.⁷

Private sales must be recorded through the Massachusetts Gun Transaction Portal. Print or save the Firearms Transaction (EFA10) form and receipt immediately after completing the transaction online, because the record cannot be retrieved after the page closes.⁸

1
General Court of Massachusetts. Massachusetts General Laws Chapter 140, Section 121
2
General Court of Massachusetts. Massachusetts General Laws Chapter 140, Section 131M
3
Mass.gov. 501 CMR 20.00 – Serialization of Firearms
4
General Court of Massachusetts. Massachusetts General Laws Chapter 269, Section 10
5
General Court of Massachusetts. Acts of 2024 Chapter 135 – An Act Modernizing Firearm Laws
6
Mass.gov. Mass. General Laws c.140, Section 131L
7
Mass.gov. Mass. General Laws c.140, Section 121B
8
Mass.gov. Record a Private Firearms Sale or Registration