Massachusetts Restricted Weapon Categories and Federal NFA Items

Massachusetts Restricted Weapon Categories and Federal NFA Items

Two bodies of law reach the weapons commonly grouped under the National Firearms Act. Federal law imposes registration, tax and transfer duties through Titles 26 and 18 of the United States Code. Massachusetts defines its own weapon categories in MGL c. 140, s. 121 and sets its own licensing conditions and penalties. A federal registration answers a federal duty. It is not among the exempted statuses in any of the state offense statutes set out below.

St. 2024, c. 135, approved July 25, 2024, restructured s. 131, which now runs from subsection (a) through subsection (h). Eligibility, denial, suitability, appeals, fees and renewal moved to MGL c. 140, s. 121F.

The section 121 definitions that control

Section 121 supplies the vocabulary for ss. 122 to 131Y of c. 140.

Section 121 separately defines "Automatic conversion," "Bump stock," "Trigger modifier" (including "trigger cranks, binary triggers and hellfire triggers") and "Rapid-fire trigger activator," each turning on a device or modification that increases a firearm's rate of fire. Bump stock, trigger modifier and rapid-fire trigger activator, along with automatic part and sawed-off shotgun, are the articles c. 269, s. 10(c) reaches. Automatic conversion is defined as "any modification made to a firearm" rather than as an article, and it does its work inside the machine gun definition rather than in the s. 10(c) list.

Large capacity firearm: the clause that turns on a vehicle

Section 121 defines a "Large capacity firearm" as "any firearm that: (i) is semiautomatic with a fixed large capacity feeding device; (ii) is semiautomatic and capable of accepting, or readily modifiable to accept, any detachable large capacity feeding device when both are in the same person's possession or under their control in a vehicle; (iii) employs a rotating cylinder capable of accepting more than 10 rounds of ammunition or more than 5 shotgun shells; or (iv) is an assault-style firearm."

Clause (ii) carries a predicate and a trigger, and both do work. The predicate is that the firearm be "semiautomatic and capable of accepting, or readily modifiable to accept, any detachable large capacity feeding device." The trigger is "when both are in the same person's possession or under their control in a vehicle."

The definition continues: "provided, however, that ''large capacity firearm'' shall be a secondary designation and shall apply to a firearm in addition to its primary designation as a firearm, and shall not include, any firearm that: (a) operates by manual bolt, pump, lever or slide action; (b) is a single-shot firearm; (c) has been modified so as to render it permanently inoperable or otherwise rendered permanently unable to be designated a large capacity firearm; or (d) is an antique or relic, theatrical prop or other firearm that is not capable of firing a projectile and which is not intended for use as a functional firearm and cannot be readily modified through a combination of available parts into an operable large capacity firearm."

A "Large capacity feeding device" is "(i) a fixed or detachable magazine, belt, drum, feed strip or similar device that has a capacity of, or that can be readily converted to accept, more than 10 rounds of ammunition or more than 5 shotgun shells; or (ii) any part or combination of parts from which a device can be assembled if those parts are in the possession or control of the same person; provided, however, that ''large capacity feeding device'' shall not include: (a) any device that has been permanently altered so that it cannot accommodate more than 10 rounds of ammunition or more than 5 shotgun shells; (b) an attached tubular device designed to accept and capable of operating only with.22 caliber rimfire ammunition; or (c) a tubular magazine that is contained in a lever-action firearm or on a pump shotgun."

Machine guns under Massachusetts law

MGL c. 140, s. 131(a) entitles a license holder "to purchase, rent, lease, borrow, possess and carry firearms, including large capacity firearms and ammunition therefor," but not "to transfer, possess or carry large capacity feeding devices or assault-style firearms unless such transfer, possession or carry is permitted under section 131M."

Machine gun authority is separate, in s. 131(f): "No person shall be issued a license to carry a machine gun in the commonwealth, except that a licensing authority may issue a machine gun license to: (i) a firearm instructor certified by the municipal police training committee for the sole purpose of firearm instruction to police personnel; or (ii) a bona fide collector of firearms as defined in section 121 upon application or upon application for renewal of such license. Clauses (i) and (ii) of this paragraph shall not apply to automatic devices or automatic parts."

A "Bona fide collector of firearms" is "a licensed collector pursuant to 18 U.S.C. section 923(b)."

The offense is MGL c. 269, s. 10(c): "Whoever, except as provided by law, possesses a machine gun, as defined in section one hundred and twenty-one of chapter one hundred and forty, without permission under section one hundred and thirty-one of said chapter one hundred and forty; or whoever owns, possesses or carries on his person, or carries on his person or under his control in a vehicle, a sawed-off shotgun, automatic part, bump stock, rapid-fire trigger activator or trigger modifier, as those terms are defined in said section one hundred and twenty-one of said chapter one hundred and forty, shall be punished by imprisonment in the state prison for life, or for any term of years provided that any sentence imposed under the provisions of this paragraph shall be subject to the minimum requirements of paragraph (a)."

The parallel enumerations in section 10(a)

Section 10(a) contains parallel enumerations, one for a firearm and one for a rifle or shotgun, and their clause (4) is not the same. On the firearm branch it is "having complied with the provisions of sections one hundred and twenty-nine C and one hundred and thirty-one G." St. 2024, c. 135, SECTION 64 repealed MGL c. 140, s. 131G, so the second half of that cross-reference no longer points to a live section. On the rifle or shotgun branch it is "having in effect a firearms identification card issued under section one hundred and twenty-nine B." Clause (1) on each branch, "being present in or on his residence or place of business," defeats liability on its own, and no holder of a license under s. 131 or s. 131F "shall be deemed to be in violation of this section." Conviction carries 2 1/2 to 5 years in state prison, or 18 months to 2 1/2 years "in a jail or house of correction," with an 18 month floor that cannot be suspended and no eligibility for "probation, parole, work release, or furlough or receive any deduction from his sentence for good conduct" until 18 months are served.

Silencers and suppressors

MGL c. 269, s. 10A reaches any person who "sells or keeps for sale, or offers, or gives or disposes of by any means other than submitting to an authorized law enforcement agency, or uses or possesses any instrument, attachment, weapon or appliance for causing the firing of any gun, revolver, pistol or other firearm to be silent or intended to lessen or muffle the noise of the firing," and reaching "any combination of parts designed or redesigned and intended for use in assembling or fabricating" such a device. It excepts, by its own terms, a federally licensed firearms manufacturer, an authorized agent of the municipal police training committee, a duly authorized sworn officer acting within the scope of official duties under the direct authorization of the police chief or a designee, and the colonel of the state police, and it preserves federally licensed manufacturer sales "to authorized law enforcement agencies for law enforcement purposes or to the municipal police training committee for law enforcement training." On conviction, the article "shall be confiscated by the commonwealth and forwarded, by the authority of the written order of the court, to the colonel of the state police, who shall destroy said article."

The exceptions are only those the section names. An approved federal registration is not among them. Federal law calls the same hardware a "firearm silencer" in 18 U.S.C. 921, where the terms "firearm silencer" and "firearm muffler" mean "any device for silencing, muffling, or diminishing the report of a portable firearm, including any combination of parts, designed or redesigned, and intended for use in assembling or fabricating a firearm silencer or firearm muffler, and any part intended only for use in such assembly or fabrication." That parts language runs close to the parts language in s. 10A. Federal tax law then borrows the term: 26 U.S.C. 5845(a)(7) brings "any silencer (as defined in section 921 of title 18, United States Code)" into the National Firearms Act by reference.

Assault-style firearms and large capacity feeding devices under section 131M

MGL c. 140, s. 131M(a): "No person shall possess, own, offer for sale, sell or otherwise transfer in the commonwealth or import into the commonwealth an assault-style firearm, or a large capacity feeding device."

Subsection (b) sets the August 1, 2024 carve-out: subsection (a) "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."

Subsection (c) sets the September 13, 1994 carve-out. It applies "to large capacity feeding devices lawfully possessed on September 13, 1994 only if such possession is: (i) on private property owned or legally controlled by the person in possession of the large capacity feeding device; (ii) 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; (iii) while on the premises of a licensed firearms dealer or gunsmith for the purpose of lawful repair; (iv) at a licensed firing range or sports shooting competition venue; or (v) while traveling to and from these locations; provided, that the large capacity feeding device is stored unloaded and secured in a locked container in accordance with sections 131C and 131L." Such a person "may only transfer the device to an heir or devisee, a person residing outside the commonwealth, or a licensed dealer."

Subsection (e) was amended by St. 2025, c. 14, s. 45, effective August 5, 2025. The amended text is the operative one. Under it, s. 131M "shall not apply to transfer or possession by: (i) a qualified law enforcement officer or a qualified retired law enforcement officer, as defined in the Law Enforcement Officers Safety Act of 2004, 18 U.S.C. sections 926B and 926C, respectively, as amended; (ii) a law enforcement officer as defined in section 1 of chapter 6E who is currently certified pursuant to section 4 of said chapter 6E; provided, however, that to qualify for the exemption under this subsection, the certification of a law enforcement officer as defined in section 1 of chapter 6E shall not be suspended, limited, or restricted and the officer shall be permitted to perform police duties and functions involving firearms in accordance with chapter 6E and the regulations promulgated thereunder; (iii) a federal, state or local law enforcement agency; or (iv) a federally licensed manufacturer solely for sale or transfer in another state or for export."

The s. 121 definition of "Assault-style firearm" applies a feature test to semiautomatic centerfire rifles, and to semiautomatic pistols and shotguns, and also captures the s. 131 3/4 roster, an enumerated model list, and copies. Its exclusion clause provides that the term "shall not include any: (i) firearm that is operated by manual bolt, pump, lever or slide action; (ii) firearm that has been rendered permanently inoperable or otherwise rendered permanently unable to be designated as a semiautomatic assault-style firearm; (iii) firearm that is an antique or relic, theatrical prop or other firearm that is not capable of firing a projectile and which is not intended for use as a functional firearm and cannot be readily modified through a combination of available parts into an assault-style firearm; (iv) any of the firearms, or replicas or duplicates of such firearms, specified in appendix A to 18 U.S.C. section 922 as appearing in such appendix on September 13, 1994, as such firearms were manufactured on October 1, 1993; or (v) semiautomatic shotgun that cannot hold more than 5 rounds of ammunition in a fixed or detachable feeding device."

The large capacity possession offense

MGL c. 269, s. 10(m) applies to "any person not exempted by statute who knowingly has in his possession, or knowingly has under his control in a vehicle, a large capacity firearm or large capacity feeding device therefor who does not possess a valid license to carry firearms issued under section 131 or 131F of chapter 140, except as permitted or otherwise provided under this section or chapter 140."

The penalty is "imprisonment in a state prison for not less than two and one-half years nor more than ten years," and the sentence "shall not be reduced to less than one year, nor suspended," with no probation or parole until the minimum is served. The subsection addresses the FID card directly: "The possession of a valid firearm identification card issued under section 129B shall not be a defense for a violation of this subsection; provided, however, that any such person charged with violating this paragraph and holding a valid firearm identification card shall not be subject to any mandatory minimum sentence imposed by this paragraph."

The paragraph then supplies its own exemptions. It "shall not apply to the possession of a large capacity firearm or large capacity feeding device by (i) any officer, agent or employee of the commonwealth or any other state or the United States, including any federal, state or local law enforcement personnel; (ii) any member of the military or other service of any state or the United States; (iii) any duly authorized law enforcement officer, agent or employee of any municipality of the commonwealth; (iv) any federal, state or local historical society, museum or institutional collection open to the public; provided, however, that any such person described in clauses (i) to (iii), inclusive, is authorized by a competent authority to acquire, possess or carry a large capacity semiautomatic weapon and is acting within the scope of his duties; or (v) any gunsmith duly licensed under the applicable federal law."

Covert and undetectable firearms

MGL c. 140, s. 131N: "No person shall knowingly possess, own, sell, offer for sale, transfer, manufacture, assemble, repair or import any firearm capable of discharging a bullet or shot that is a covert firearm or an undetectable firearm all as defined in section 121."

A "Covert firearm" is one "placed in a camouflaging firearm container, or a firearm that is not a stun gun," capable of discharging a bullet or shot and "constructed in a shape that does not resemble a firearm or is not immediately recognizable as a firearm," such as a zip gun or folding gun. An "Undetectable firearm" is one that, after removal of grips, stocks and magazines, "is not detectable by walk-through metal detectors calibrated and operated to detect the security exemplar as defined in 18 U.S.C. Section 922(p)(2)(C)," or "a major component of a firearm as defined in 18 U.S.C. Section 922(p)(2)(B) that, when inspected by detection devices commonly used at secure public buildings and transit stations, does not generate an image that accurately depicts the shape of the component."

The federal layer

What the National Firearms Act defines as a firearm

26 U.S.C. 5845(a) supplies the federal vocabulary. The term "firearm" means "(1) a shotgun having a barrel or barrels of less than 18 inches in length; (2) a weapon made from a shotgun if such weapon as modified has an overall length of less than 26 inches or a barrel or barrels of less than 18 inches in length; (3) a rifle having a barrel or barrels of less than 16 inches in length; (4) a weapon made from a rifle if such weapon as modified has an overall length of less than 26 inches or a barrel or barrels of less than 16 inches in length; (5) any other weapon, as defined in subsection (e); (6) a machinegun; (7) any silencer (as defined in section 921 of title 18, United States Code); and (8) a destructive device." The same subsection carves out antiques and collector's items: the term "shall not include an antique firearm or any device (other than a machinegun or destructive device) which, although designed as a weapon, the Secretary finds by reason of the date of its manufacture, value, design, and other characteristics is primarily a collector's item and is not likely to be used as a weapon."

Subsection (b) defines "machinegun" as "any weapon which shoots, is designed to shoot, or can be readily restored to shoot, automatically more than one shot, without manual reloading, by a single function of the trigger," and adds that the term "shall also include the frame or receiver of any such weapon, any part designed and intended solely and exclusively, or combination of parts designed and intended, for use in converting a weapon into a machinegun, and any combination of parts from which a machinegun can be assembled if such parts are in the possession or under the control of a person."

Subsection (e) defines "any other weapon" as "any weapon or device capable of being concealed on the person from which a shot can be discharged through the energy of an explosive, a pistol or revolver having a barrel with a smooth bore designed or redesigned to fire a fixed shotgun shell, weapons with combination shotgun and rifle barrels 12 inches or more, less than 18 inches in length, from which only a single discharge can be made from either barrel without manual reloading," including "any such weapon which may be readily restored to fire." It does not include "a pistol or a revolver having a rifled bore, or rifled bores, or weapons designed, made, or intended to be fired from the shoulder and not capable of firing fixed ammunition."

Subsection (f) defines "destructive device" as "(1) any explosive, incendiary, or poison gas (A) bomb, (B) grenade, (C) rocket having a propellent charge of more than four ounces, (D) missile having an explosive or incendiary charge of more than one-quarter ounce, (E) mine, or (F) similar device; (2) any type of weapon by whatever name known which will, or which may be readily converted to, expel a projectile by the action of an explosive or other propellant, the barrel or barrels of which have a bore of more than one-half inch in diameter, except a shotgun or shotgun shell which the Secretary finds is generally recognized as particularly suitable for sporting purposes; and (3) any combination of parts either designed or intended for use in converting any device into a destructive device as defined in subparagraphs (1) and (2) and from which a destructive device may be readily assembled." The same subsection closes with an exclusion: the term "shall not include any device which is neither designed nor redesigned for use as a weapon; any device, although originally designed for use as a weapon, which is redesigned for use as a signaling, pyrotechnic, line throwing, safety, or similar device", along with surplus ordnance sold, loaned or given by the Secretary of the Army under the cited provisions, and any other device the Secretary finds is not likely to be used as a weapon. That exclusion matters here because destructive device is one of the two categories still carrying the $200 transfer tax.

Set beside s. 121, the federal machinegun definition differs in ways the two texts make explicit. The federal test is "a single function of the trigger," while the s. 121 test is "a continuous activation of the trigger" and carries a second branch, for a firearm "modified by automatic conversion to alter or increase its rate of fire to mimic automatic fire," that has no counterpart in 5845(b). And the federal machinegun definition reaches "any combination of parts from which a machinegun can be assembled if such parts are in the possession or under the control of a person," which is the same possession-of-parts structure s. 121 uses in clause (ii) of "Large capacity feeding device," "any part or combination of parts from which a device can be assembled if those parts are in the possession or control of the same person."

The transfer tax and the transfer conditions

26 U.S.C. 5811(a) is the transfer tax, and its rate now turns on what is being transferred. There "shall be levied, collected, and paid on firearms transferred a tax," set by paragraph (1) at "$200 for each firearm transferred in the case of a machinegun or a destructive device" and by paragraph (2) at "$0 for any firearm transferred which is not described in paragraph (1)." The tax "shall be paid by the transferor" and "shall be payable by the appropriate stamps prescribed for payment by the Secretary."

That structure is new. Subsection (a) was amended generally by Pub. L. 119-21, title VII, s. 70436(a), July 4, 2025, and the amendment is "applicable to calendar quarters beginning more than 90 days after July 4, 2025." The text it replaced levied "$200 for each firearm transferred," excepting a firearm "classified as any other weapon under section 5845(e)," which was taxed "at the rate of $5 for each such firearm transferred." Under the operative text a silencer, a short-barreled rifle, a short-barreled shotgun and a weapon classified as any other weapon all fall in paragraph (2) and are taxed at $0. The $200 figure survives only for a machinegun or a destructive device.

26 U.S.C. 5812(a) sets the conditions. A firearm "shall not be transferred unless" the transferor "has filed with the Secretary a written application, in duplicate, for the transfer and registration of the firearm to the transferee on the application form prescribed by the Secretary"; "any tax payable on the transfer is paid as evidenced by the proper stamp affixed to the original application form"; the transferee is identified in the application form, "except that, if such person is an individual, the identification must include his fingerprints and his photograph"; the transferor is identified in the application form; the firearm is identified in the application form; and "the application form shows that the Secretary has approved the transfer and the registration of the firearm to the transferee." Subsection (b) adds that "the transferee of a firearm shall not take possession of the firearm unless the Secretary has approved the transfer and registration of the firearm to the transferee as required by subsection (a) of this section."

The closing line of 5812(a) is where the federal scheme points back at state law: "Applications shall be denied if the transfer, receipt, or possession of the firearm would place the transferee in violation of law." Approval is conditioned on the transferee's lawfulness, so the Massachusetts offenses set out above bear on the federal application rather than being answered by it.

Federal offenses and penalties

The exceptions in 18 U.S.C. 922(o)(2) are narrow: possession under government authority, and "any lawful transfer or lawful possession of a machinegun that was lawfully possessed before the date this subsection takes effect." The 922(p) row is graded by 18 U.S.C. 924(f) rather than by the residual clause in 924(a)(1)(D). Subsection (f) names 922(p) expressly, and 924(a)(1) opens "Except as otherwise provided in this subsection, subsection (b), (c), (f), or (p) of this section, or in section 929," so it yields to subsection (f) on its own terms. The difference is the mental state, not the ceiling: 924(f) reaches a person who "knowingly violates section 922(p)," while the residual clause requires a willful violation.

Section 921 defines a "short-barreled shotgun" as "a shotgun having one or more barrels less than eighteen inches in length and any weapon made from a shotgun (whether by alteration, modification or otherwise) if such a weapon as modified has an overall length of less than twenty-six inches," and a "short-barreled rifle" as "a rifle having one or more barrels less than sixteen inches in length and any weapon made from a rifle (whether by alteration, modification, or otherwise) if such weapon, as modified, has an overall length of less than twenty-six inches." Each of those definitions carries an overall-length branch that operates independently of the barrel figure. The s. 121 definitions quoted above, not these, drive MGL c. 269, s. 10(c).

The rifle side and the shotgun side do not line up. Federally, 26 U.S.C. 5845(a) reaches "a rifle having a barrel or barrels of less than 16 inches in length" and "a weapon made from a rifle if such weapon as modified has an overall length of less than 26 inches or a barrel or barrels of less than 16 inches in length," so the registration duty in 26 U.S.C. 5861(d) attaches to such a weapon. The s. 121 "Rifle" definition uses the same 16 inch figure as its floor, so a rifled-bore firearm below it is not a "Rifle" for Massachusetts purposes. That is a definitional consequence and nothing more. On the shotgun side there is a Massachusetts counterpart: "Sawed-off shotgun" is defined in s. 121 and named as an offense object in c. 269, s. 10(c). No Massachusetts provision cited on this page names a short-barreled rifle; the term appears here only in the federal definitions quoted above.

Licenses in force when the 2024 act took effect

St. 2024, c. 135, SECTION 153: "A valid license to carry a firearm issued under sections 131 or 131F of chapter 140 of the General Laws, a valid firearm identification card under section 129B of said chapter 140 or a valid license to sell under section 122 of said chapter 140, shall remain valid until the expiration, suspension or revocation of said license and shall entitle the holder to possess the firearms authorized by the license at the time it was last issued or renewed."

Penalty summary

How the pieces fit

A license to carry does what s. 131(a) says it does. It does not by itself reach large capacity feeding devices or assault-style firearms, which run through s. 131M, and it does not reach machine guns, which run through the separate license in s. 131(f).

Registration in the National Firearms Registration and Transfer Record answers 26 U.S.C. 5861(d). It does not answer MGL c. 269, s. 10(c), s. 10(m) or s. 10A, or MGL c. 140, s. 131M or s. 131N, each with its own exemptions where the statute provides any, and s. 131N provides none at all. Work through the s. 121 definitions first, then the matching state offense statute, then the federal duties, and consult a Massachusetts attorney.