Massachusetts Firearms Law. Decoded.

Firearm. "A stun gun, pistol, revolver, rifle, shotgun, sawed-off shotgun, large capacity firearm, assault-style firearm and machine gun, loaded or unloaded, which is designed to or may readily be converted to expel a shot or bullet" — expressly including a frame or receiver, and an unfinished frame or receiver, of any of the above. Antique firearms and permanently inoperable firearms are excluded.

Frame. The part of a pistol or revolver that provides housing or a structure for the component designed to hold back the hammer, striker, bolt or similar primary energized component prior to initiation of the firing sequence. A part bearing an importer or manufacturer serial number is presumed to be the frame absent an official ATF determination otherwise.

Receiver. The part of a rifle or shotgun that provides housing or a structure for the primary component designed to block or seal the breech prior to initiation of the firing sequence. The same serial-number presumption applies.

Unfinished frame or receiver. A forging, casting, printing, extrusion, machined body or similar item that has either reached a stage where it may readily be completed, OR is marketed or sold to become a frame or receiver. The statute uses the word "unfinished" without an "80% lower" carve-out.

Privately made firearm. A firearm assembled or otherwise produced by a person other than a licensed manufacturer or importer.

Antique firearm. A firearm manufactured in or before 1899, not designed for rimfire or conventional centerfire fixed ammunition; or a muzzle-loading rifle, shotgun or pistol designed to use black powder or a black powder substitute that cannot use fixed ammunition.

Assault-style firearm. Defined in §121 by six routes — the three features tests (rifle, pistol, shotgun), the FCAB roster (§128A), the enumerated list (AK, UZI, Galil, Beretta AR70, Colt AR-15, FN/FAL/LAR/FNC, SWD M-10/M-11/M-11/9/M-12, Steyr AUG, INTRATEC TEC-9/DC9/22, revolving-cylinder shotguns), and any "copy or duplicate" of the last route. Spelled out in Section 02.

Large capacity feeding device. A fixed or detachable magazine, belt, drum, feed strip or similar device that holds, or can be readily converted to hold, more than 10 rounds of ammunition or more than 5 shotgun shells; or any combination of parts from which such a device can be assembled. Excludes: devices permanently altered to under that capacity; .22 rimfire-only attached tubular devices; tubular magazines in lever-action firearms or pump shotguns.

Machine gun. A weapon of any description loaded or unloaded, that fires automatically more than one shot by a single function of the trigger.

Machine gun conversion device. Any part or combination of parts designed and intended to convert a semi-automatic firearm into a machine gun; expressly includes auto sears, "Glock switches," and trigger cranks.

Rapid-fire trigger activator. Any manual, power-driven or electronic device designed to increase the rate of fire of a semi-automatic firearm; or any other device, part or combination of parts designed to substantially increase rate of fire above the standard rate. Adjusting trigger pull weight or replacing a magazine spring is not included.

Self-defense spray. Defined in §121 as a chemical or chemical compound — including oleoresin capsicum (OC, "pepper spray") — that is intended for self-defense.

The ban "shall not apply to an assault-style firearm lawfully possessed within the commonwealth on August 1, 2024, by an owner in possession of a license to carry issued under section 131 or by a holder of a license to sell under section 122; provided, that the assault-style firearm shall be registered in accordance with section 121B and serialized in accordance with section 121C."

For large capacity feeding devices, §131M(c) preserves possession of LCFDs lawfully possessed on September 13, 1994 only on private property the possessor owns or controls, on private property not open to the public with the owner's express permission, or at a licensed shooting range or club.

• A frame or receiver, finished or unfinished, is a firearm and may not be possessed without the appropriate license.
• A part identified with an importer or manufacturer serial number is presumed to be the frame or receiver, absent an official ATF determination otherwise.
• If a frame or receiver would make the resulting firearm an enumerated ASF or a copy/duplicate of one, §131M's prohibition applies; the §121(f) "Mass Compliant" exemption is only available if the firearm was lawfully possessed, registered, and serialized in MA prior to July 20, 2016 with fewer than two listed features.
• If a frame or receiver would meet the §121 features test, the resulting firearm is an ASF and falls under §131M unless covered by the §131M(b) August 1, 2024 grandfather (lawfully possessed, registered under §121B, serialized under §121C, and held by a §131 LTC holder or §122 dealer).

An LCFD is a fixed or detachable magazine, belt, drum, feed strip or similar device that holds, or can be readily converted to hold, more than 10 rounds of ammunition or more than 5 shotgun shells; or any combination of parts from which such a device can be assembled if those parts are in the possession or control of the same person.

Excludes: devices permanently altered so they cannot accommodate more than 10 rounds (or 5 shells); attached tubular devices designed only for .22 rimfire; tubular magazines in lever-action firearms or pump shotguns.

§131M(a) bans possession, ownership, sale, transfer, and importation of any LCFD in the Commonwealth.

§131M(c) preserves possession of LCFDs lawfully possessed on September 13, 1994 only if the possession is (i) on private property the possessor owns or legally controls, (ii) on private property not open to the public with the owner's express permission, or (iii) at a licensed shooting range or club. There is no general §131M grandfather for LCFDs based on August 1, 2024 possession — the cutoff is the 1994 federal date.

Machine guns are prohibited under M.G.L. c. 140 §131 except for licensed dealers and law enforcement; Chapter 135 added MCDs and rapid-fire trigger activators as separate prohibited categories. Possession of an MCD is treated like possession of an unregistered machine gun.

Rapid-fire trigger activator — any device, manual, power-driven, or electronic, designed to increase the rate of fire of a semi-automatic firearm above its standard rate — is also prohibited. Adjusting trigger pull weight or replacing a magazine spring is expressly excluded.

• Every firearm in the Commonwealth must bear a serial number traceable through ATF or, for privately made firearms, a serial number obtained from the Department of Criminal Justice Information Services (DCJIS).
• A privately made firearm must be serialized within the time the statute prescribes from the date of manufacture or assembly.
• All firearms transferred or possessed must be registered with the Commonwealth through the DCJIS Massachusetts Instant Records Check System (MIRCS) or its successor portal.
• Newly acquired firearms must be reported to DCJIS within seven days of transfer under §128A and §129C.
• Privately made firearms (frames, receivers, completed builds) must be serialized and registered before they may be lawfully possessed.

• The basic firearms safety course must include classroom instruction and a live-fire component, on a curriculum approved by the Colonel of the State Police.
• A hunter education certificate issued under M.G.L. c. 131 §14 satisfies the requirement for an FID, but not for an LTC.
• Persons who lawfully held an FID or LTC on August 1, 2024 are exempt from the new certificate requirement at renewal — with a proviso that those licensed before live-fire was actually implemented may be subject to additional requirements at renewal.
• Instructors must be certified by the Colonel and meet the §131P training and recordkeeping requirements.

• FID = non-large-capacity, non-semi-automatic rifles and shotguns, plus their ammunition.
• An FID does not entitle the holder to transfer, possess, or carry any large capacity firearm, any large capacity or semi-automatic rifle, or any large capacity or semi-automatic shotgun — except "under the direct supervision of a holder of a license to carry firearms at an incorporated shooting club or a licensed shooting range."
• An FID is also valid for self-defense spray (§122D), which an LTC also covers.
• Handguns of any kind require an LTC under §131. An FID never authorizes possession of a handgun outside the limited §130½ FID-for-handgun-at-home framework where applicable.

• An FID is required to possess any rifle or shotgun, including those used solely for hunting.
• A semi-automatic hunting rifle or shotgun requires an LTC under §129B(c) — an FID alone is not sufficient.
• A hunter education certificate under c. 131 §14 may serve in place of the basic firearms safety certificate when applying for an FID under §131P, but not when applying for an LTC.
• The black powder firearm exemption is governed by the antique-firearm and muzzle-loader provisions of §121 (see Section 10).

• An antique firearm meeting the §121 definition is excluded from the §121 definition of "firearm," meaning the FID/LTC requirements applicable to firearms do not apply to it as a matter of statute.
• The antique exemption requires that the firearm cannot use fixed ammunition. A muzzle-loader converted or readily convertible to fire fixed ammunition is treated as a firearm.
• Possession of black powder propellant and components is regulated separately under M.G.L. c. 148 (storage) and federal law; Chapter 135 did not add a separate state-license requirement for the propellant itself.

• A non-resident may apply to the Colonel of the State Police for a temporary license to carry under §131F. The license is good for one year and may be limited by purpose (e.g., hunting, sporting, employment).
• A non-resident's firearm brought into the Commonwealth must be registered consistent with §129C, except where the firearm is being transported in compliance with the federal Firearm Owners Protection Act (FOPA, 18 U.S.C. §926A).
• An assault-style firearm or large capacity feeding device may not be brought into the Commonwealth by a non-resident even with a temporary license, because §131M's prohibition is not limited to residents.

• If an FID or LTC is suspended or revoked, the holder must, without delay, surrender all firearms, ammunition, feeding devices, and the license itself to the licensing authority that issued it.
• The holder may, with the licensing authority's written approval, transfer surrendered firearms to a licensed dealer or to a person legally permitted to possess them.
• Failure to surrender is itself a criminal offense and may result in additional charges.

• A family or household member, or a law enforcement officer, may petition for an ERPO if a person poses a risk of causing bodily injury to self or others.
• An ERPO suspends the respondent's FID or LTC and requires surrender of all firearms, ammunition, and LCFDs while the order is in effect.
• The respondent has the right to a hearing within ten days; the order may be extended for up to one year and renewed.

• A §122 dealer may sell, transfer, repair, or store firearms at the licensed premises only, subject to the conditions in §123.
• Every transfer must be recorded electronically through the DCJIS portal at the time of sale and reported in real time.
• Dealers must inspect each firearm before sale to confirm the serial number is legible and traceable; sale of a firearm with an obliterated or unserialized frame or receiver (other than as authorized for §122F gunsmith repair) is prohibited.
• A §122 license does not exempt a dealer from §131M; a licensed dealer may not sell, transfer, or possess an assault-style firearm or LCFD except where covered by the §131M(b)/(c) statutory carve-outs.
• Background checks must be completed through MIRCS or NICS for every transfer, including private transfers facilitated by a dealer.

• A person 18 years of age or older may purchase and possess self-defense spray without an FID or LTC, provided the spray is purchased from a licensed dealer in the Commonwealth.
• A person at least 15 but under 18 may purchase and possess self-defense spray with parental consent and an FID restricted under §129B for that purpose.
• Sale of self-defense spray is restricted to dealers licensed under §122 or §122B.
• Possession by a person prohibited from possessing a firearm (e.g., due to a disqualifying conviction or restraining order) is itself a criminal offense.