Possession of a Large Capacity Firearm or Feeding Device in Massachusetts: G.L. c. 269, § 10(m)

A person found with a semiautomatic pistol that takes a magazine of more than ten rounds, or with the magazine itself, without a Massachusetts license to carry, is charged with possession of a large capacity firearm or large capacity feeding device under G.L. c. 269, § 10(m). The charge is added to a carrying charge under § 10(a) after a traffic stop or a street encounter. After a search of a home, it is brought on its own. Most modern semiautomatic pistols meet the definition, so the charge appears in a large share of Massachusetts gun cases.

If a defendant is convicted, the sentence is state prison. The judge must set a maximum term of at least two and one half years and no more than ten years, and a minimum term of at least one year. The defendant is not eligible for probation, parole, furlough, work release, or good conduct credit until the minimum term is served. A defendant who held a valid firearm identification card is not subject to the mandatory minimum.

The statute bars a continuance without a finding, bars placing the case on file, and bars pretrial probation for a defendant 18 or older. The case can be tried only in the Superior Court. The charge is a predicate for a dangerousness hearing.

This page explains what counts as a large capacity firearm or feeding device, what the Commonwealth must prove, and the knowledge rule that has reversed convictions. It covers the license element, the sentence, the separate ban on assault-style firearms and magazines under G.L. c. 140, § 131M, and the defenses. Attorney Joe Serpa has practiced Massachusetts criminal defense since 1995 and defends firearms charges in the Boston Municipal Court, the District Courts of Greater Boston, and the Superior Court.

What Counts as a Large Capacity Firearm or Feeding Device

G.L. c. 140, § 121 defines a large capacity feeding device as “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.” Parts from which such a device can be assembled count if one person possesses them all. The definition excludes a device permanently altered so that it cannot hold more than ten rounds, an attached tubular device that works only with .22 caliber rimfire ammunition, and a tubular magazine in a lever-action firearm or a pump shotgun.

A large capacity firearm is a firearm that is semiautomatic with a fixed large capacity feeding device, or that 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.” It also includes a firearm with a rotating cylinder that holds more than ten rounds or more than five shotgun shells, and any assault-style firearm. G.L. c. 140, § 121. A firearm that operates by manual bolt, pump, lever, or slide action, a single-shot firearm, and a firearm permanently altered so that it cannot be a large capacity firearm are excluded.

The words “when both are in the same person’s possession or under their control in a vehicle” were added by St. 2024, c. 135, effective October 2, 2024. Before that date, a semiautomatic pistol that could accept a large capacity magazine was a large capacity weapon whether or not any such magazine was present. For an offense on or after that date, the Commonwealth must prove that the defendant possessed both the firearm and the detachable device, unless the firearm falls within another clause of the definition. No appellate court has yet construed the new words.

The Elements

To convict a defendant under § 10(m), the Commonwealth must prove four elements beyond a reasonable doubt. First, the defendant knowingly possessed the object, or knowingly had it under their control in a vehicle. Second, the object met the legal definition of a large capacity firearm or a large capacity feeding device. Third, the defendant knew that the object met that definition or knew that it could hold more than ten rounds of ammunition or more than five shotgun shells. Fourth, the defendant did not have a valid license to carry firearms at the time.

Where the evidence raises a statutory exemption, the Commonwealth must also prove that the exemption does not apply. The Superior Court’s model instruction on unlawful possession of a large capacity firearm or feeding device (July 14, 2026) states the elements in that form.

The District Court has no model instruction for this offense, because it has no jurisdiction over it. Section 10(m) is punishable by up to ten years in state prison. G.L. c. 218, § 26 limits the District Court to felonies punishable by five years or less unless a statute lists the offense. Section 10(m) is not listed. The case begins with an arraignment in the District Court, but the Commonwealth must obtain an indictment and try it in the Superior Court.

The Knowledge Rule

The Commonwealth must prove that the defendant knew the firearm or magazine was large capacity. “We conclude that, to sustain a conviction under G. L. c. 269, § 10 (m), the Commonwealth must prove that a defendant either knew the firearm or feeding device met the legal definition of ‘large capacity’ or knew it was capable of holding more than ten rounds of ammunition.” Commonwealth v. Cassidy, 479 Mass. 527, 529 (2018). The Commonwealth does not have to prove that the defendant knew the law required a license. Commonwealth v. Jackson, 369 Mass. 904, 916-917 (1976).

In Cassidy, the evidence was sufficient. The defendant had owned and fired his guns for years, had bought an extended magazine separately, and testified that he never fully loaded it so as not to wear out the spring. The magazines were “noticeably larger” than a ten-round magazine. Cassidy, 479 Mass. at 537. The defendant’s familiarity with his own weapons supported the inference of knowledge. Cassidy, 479 Mass. at 537-538.

The rule has reversed convictions. In Commonwealth v. Resende, 94 Mass. App. Ct. 194 (2018), the police took a pistol from the defendant’s waistband with a 15-round magazine inside it, loaded with 14 rounds. The magazine did not protrude. The defendant said a friend had given him the gun. The Appeals Court held that the Commonwealth failed to prove knowledge, vacated the § 10(m) conviction, and entered judgment for the defendant. Resende, 94 Mass. App. Ct. at 202.

In a 2018 decision, the Appeals Court reversed a conviction based on an empty 13-round magazine wrapped in a bandanna inside a closed ammunition box. The defendant said he had gotten the gun days before and had never fired it. Commonwealth v. Cintron, No. 16-P-1698 (Mass. App. Ct. Dec. 28, 2018) (unpublished).

The rule does not require the Commonwealth to prove that the defendant counted the rounds. In Commonwealth v. Ralph R., 100 Mass. App. Ct. 150, 164 (2021), a juvenile carried a gun in an open sweatshirt pocket with a magazine loaded with eleven rounds. The Appeals Court held that the jury could infer that he had checked whether the gun was loaded and knew what the magazine held.

A 30-round rifle magazine with the defendant’s fingerprint on it, found in a bag he had told his wife to hide, was enough in Commonwealth v. Abdul-Alim, No. 24-P-178 (Mass. App. Ct. Jan. 17, 2025) (unpublished). The size of the magazine, who owned the gun, who loaded it, and what the defendant said about it decide most of these cases.

The License Element and the FID Card

Section 10(m) applies to a person “who does not possess a valid license to carry firearms issued under section 131 or 131F of chapter 140.” A license to carry is a complete defense. The Commonwealth must prove its absence. The Supreme Judicial Court held in Commonwealth v. Guardado, 491 Mass. 666 (2023), that the absence of a license is an element of the carrying and possession offenses under § 10(a) and § 10(h), but it declined to extend that constitutional holding to § 10(m). Guardado, 491 Mass. at 693-694.

On reconsideration, the court withdrew that part of its opinion and left open whether large capacity feeding devices are arms protected by the Second Amendment. Commonwealth v. Guardado, 493 Mass. 1, 4 n.2 (2023). The Superior Court’s 2026 model instruction lists the absence of a license as an element on the strength of the statute’s own words.

A firearm identification card is no defense. The statute says so. The same sentence then gives the card its one use, at sentencing. “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.” G.L. c. 269, § 10(m). A person with an FID card and a large capacity pistol at home is guilty under § 10(m), but the judge is not bound by the minimum term.

The exemption for a new resident under G.L. c. 140, § 129C does not apply to a feeding device charge. Commonwealth v. Cornelius, 78 Mass. App. Ct. 413 (2010). The statute exempts law enforcement officers, members of the military, museums and historical collections, and federally licensed gunsmiths, each within the scope of their duties. G.L. c. 269, § 10(m).

How § 10(m) Relates to the Carrying and Possession Charges

Section 10(m) applies “notwithstanding the provisions of paragraph (a) or (h).” Carrying a firearm without a license under § 10(a) and possessing one at home without a card under § 10(h) each depend on where the gun was. Section 10(m) does not. A large capacity pistol in a nightstand, in a car, or in a pocket is charged the same way. The residence exemption that answers a § 10(a) charge does not answer this one. The firm’s pages on carrying a firearm without a license and on possession without an FID card explain those charges.

Where the same large capacity firearm supports both a § 10(a) conviction and a § 10(m) conviction, the § 10(a) conviction is a lesser included offense and must be vacated. “The only difference between the two violations is the ‘capacity’ of the firearm.” Commonwealth v. Costa, 65 Mass. App. Ct. 227, 235 (2005). Where the § 10(m) conviction falls for want of proof of knowledge, the § 10(a) conviction is reinstated. Resende, 94 Mass. App. Ct. at 194.

Each weapon and each feeding device is a separate unit of prosecution, so a defendant with one gun and three large capacity magazines faces four counts. Commonwealth v. Mazzantini, 74 Mass. App. Ct. 915 (2009). Whether a defendant can be convicted separately for the firearm and for the magazine inside it has not been decided. The 2024 wording that ties the two together supports the argument that a second count is duplicative.

Penalties and the Sentence

If a defendant is convicted under § 10(m), the sentence is imprisonment in state prison “for not less than two and one-half years nor more than ten years.” The Supreme Judicial Court has read that range to mean that the maximum term of the sentence must be at least two and one half years, while the minimum term may be as low as one year. Commonwealth v. Rodriguez, 482 Mass. 366, 370-371, 373-374 (2019); Commonwealth v. Psikarakis, SJC-13792 (Mar. 20, 2026). In Psikarakis, the court vacated sentences of one year to one year and a day.

The sentence “shall not be reduced to less than one year, nor suspended.” The defendant is not “eligible for probation, parole, furlough, work release or receive any deduction from his sentence for good conduct until he shall have served such minimum term.” G.L. c. 269, § 10(m). The commissioner of correction may grant a temporary release only to attend the funeral of a spouse or next of kin, to visit a critically ill close relative or spouse, or to obtain emergency medical services.

A defendant who held a valid firearm identification card is not subject to the mandatory minimum. The Supreme Judicial Court has described the FID card holder as subject to a different sentencing scheme, with discretion that presumably ranges from probation to ten years in state prison. Rodriguez, 482 Mass. at 368-369.

The statute’s other limits do not depend on the card. “Prosecutions commenced under this subsection shall neither be continued without a finding nor placed on file.” Pretrial probation under G.L. c. 276, § 87 is unavailable to any person 18 or older charged under the section. A continuance without a finding is therefore not a possible outcome on the charge itself. Any disposition short of a conviction requires the Commonwealth to reduce or dismiss the charge.

The charge is a predicate for a dangerousness hearing under G.L. c. 276, § 58A(1), which names paragraph (m). The statute adds a limit. The Commonwealth “may not move for an order of detention under this section based on possession of a large capacity feeding device without simultaneous possession of a large capacity firearm.” A defendant charged only with a magazine cannot be held under § 58A on that charge. The firm’s page on dangerousness hearings explains the hearing.

A defendant with a prior conviction for a violent crime or a serious drug offense faces the armed career criminal enhancement under § 10G, which the firearms defense page explains. The Commonwealth must bring the charge within six years. G.L. c. 277, § 63.

Assault-Style Firearms and Magazines Under G.L. c. 140, § 131M

A licensed gun owner is not charged under § 10(m), but a licensed owner can be charged under G.L. c. 140, § 131M. Since October 2, 2024, that statute provides that “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.” A license to carry does not cover either item unless § 131M permits it. G.L. c. 140, § 131(a).

Two grandfather clauses apply. An assault-style firearm lawfully possessed in Massachusetts on August 1, 2024 by a license holder may be kept if it is registered under § 121B and serialized under § 121C. A large capacity feeding device lawfully possessed on September 13, 1994 may be kept only in five places. Those are the owner’s own property, private property with the owner’s permission, a dealer or gunsmith for repair, a licensed range or competition, and travel to those places with the device unloaded and locked. G.L. c. 140, § 131M(b), (c).

If a defendant is convicted under § 131M of a first offense, the possible penalties are a fine of $1,000 to $10,000, imprisonment for one to ten years, or both. For a second offense, the possible penalties are a fine of $5,000 to $15,000, imprisonment for five to fifteen years, or both.

Question 9 on the November 3, 2026 ballot is a referendum on St. 2024, c. 135, the act that rewrote these definitions and § 131M. A no vote would repeal the act. The rules on this page reflect the law in effect on the date it was written.

Constitutional Challenges

Before New York State Rifle & Pistol Association v. Bruen, the Supreme Judicial Court held that the Second Amendment does not protect large capacity weapons because the right “does not protect those weapons not typically possessed by law-abiding citizens for lawful purposes.” Cassidy, 479 Mass. at 540. After Bruen, the court left open whether large capacity feeding devices are protected arms. Guardado, 493 Mass. at 4 n.2.

The First Circuit has twice declined to enjoin the Massachusetts ban, first under the earlier statute, Capen v. Campbell, 134 F.4th 660 (1st Cir. 2025), and then under the 2024 act, Recchia v. Campbell, No. 25-1817 (1st Cir. July 21, 2026). No provision of § 10(m) or § 131M is enjoined. A defendant who wants to preserve the question must raise it by motion in the trial court.

Defenses

Knowledge. The Commonwealth must prove that the defendant knew the firearm or magazine was large capacity or held more than ten rounds. A magazine that sits flush inside the grip, a gun the defendant had just received, and a defendant with no history with firearms are the facts that won Resende and Cintron.

Possession. In a car with several occupants or a shared apartment, the Commonwealth must prove knowledge of the gun together with the ability and intention to control it. The constructive possession rules described on the § 10(a) page apply.

The definition. Counsel examines whether the firearm is semiautomatic and, for an offense after October 2, 2024, whether a magazine holding more than ten rounds was in the defendant’s possession along with it. Counsel also asks whether the device is one the statute excludes, such as a .22 tubular magazine or a device permanently altered to hold ten rounds.

The license. A valid license to carry at the time is a complete defense. Counsel also holds the Commonwealth to proof of the absence of a license and preserves the question the Supreme Judicial Court left open in Guardado.

Suppression. Most § 10(m) cases begin with a car stop or a search. Where the stop, the exit order, the frisk, or the entry was unlawful, the judge suppresses the gun and the magazine. The firm’s pages on illegal searches and seizures and traffic stops and exit orders cover the motions.

Duplicative counts. A § 10(a) conviction for the same firearm is a lesser included offense of § 10(m) and must be vacated. Costa, 65 Mass. App. Ct. at 235.

The FID card at sentencing. A defendant who held a valid firearm identification card is not subject to the mandatory minimum, so counsel obtains the licensing record before any plea discussion.

Firearms Rights, Immigration, and the Record After a Conviction

A conviction under § 10(m) is a felony conviction. It makes the defendant a prohibited person under G.L. c. 140, § 121F(j), which bars a license to carry and a firearm identification card with no time limit. Federal law separately prohibits possession of a firearm by a person convicted of a crime punishable by more than one year. 18 U.S.C. § 922(g)(1).

Federal immigration law imposes its own consequences on a large capacity charge. A conviction for possessing a firearm without a license is a firearms offense that makes a noncitizen deportable under 8 U.S.C. § 1227(a)(2)(C). A plea to § 10(m) is treated the same way. Whether a conviction based only on a magazine falls within the federal definition of a firearm has not been decided. An immigration lawyer should review the exact charge, the client’s immigration status, and the court record before any plea. The same review applies before the client files a petition or sits for an interview at which an officer may ask about the arrest or the police report. The firm’s immigration consequences pages describe the review.

The arraignment creates an entry in the defendant’s criminal record. A felony conviction under § 10(m) can be sealed under G.L. c. 276, § 100A seven years after the disposition and any period of incarceration, with no new conviction in that time. A dismissal can be sealed sooner under § 100C.

Attorney Serpa’s Representation in Large Capacity Cases

Attorney Joe Serpa has practiced Massachusetts criminal defense since 1995. He defends § 10(m) charges from the District Court arraignment through the Superior Court, both as companion counts to a carrying charge and as stand-alone charges after a search. In every case he reviews the stop or the entry, the evidence of possession, the size and placement of the magazine, what the client said about the gun, and the licensing record. He then advises on a motion to suppress, a motion for a required finding on the knowledge element, a trial, or a negotiated reduction of the charge.

Frequently Asked Questions About Large Capacity Firearm Charges

Related Serpa Law Office Resources

• Massachusetts Criminal Defense of Firearms Offenses
• Carrying a Firearm Without a License in Massachusetts: G.L. c. 269, § 10(a)
• Possession of a Firearm or Ammunition Without an FID Card in Massachusetts: G.L. c. 269, § 10(h)
• Improper Storage of a Firearm in Massachusetts: G.L. c. 140, § 131L
• Firearms Offenses for Massachusetts Visitors or Out-of-State Travelers
• Massachusetts Dangerousness Hearings Under G.L. c. 276, § 58A
• Massachusetts Traffic Stops, Exit Orders, and Pretext Searches
• Illegal Searches and Seizures in Massachusetts
• Indictments and Grand Juries in Massachusetts
• Felonies and Misdemeanors in Massachusetts
• Who Can See Your Massachusetts Criminal Record
• Sealing and Expunging a Massachusetts Criminal Record
• Immigration Consequences of Massachusetts Criminal Charges