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 holding more than ten rounds, or with the magazine itself, without a Massachusetts license to carry, is charged under G.L. c. 269, § 10(m). The charge is possession of a large capacity firearm or large capacity feeding device. After a traffic stop or a street encounter, the police usually add a § 10(m) charge to a charge of carrying a firearm without a license under § 10(a).

After a search of a home, the police may bring the § 10(m) charge by itself. Most modern semiautomatic pistols meet the definition of a large capacity firearm. The police therefore bring a § 10(m) charge in many Massachusetts gun cases.

The judge must impose a state prison sentence on a convicted defendant who did not hold a valid firearm identification card. 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 defendant has served the minimum term. A defendant who held a valid firearm identification card is not subject to the mandatory minimum.

Under § 10(m), a judge cannot continue the case without a finding, cannot place the case on file, and cannot order pretrial probation for a defendant 18 or older. Placing a case on file means that, after a guilty finding, the judge imposes no sentence and leaves the case open. The case can be tried only in the Superior Court. The Commonwealth can ask a judge to hold the defendant without bail as dangerous on a § 10(m) charge.

This page explains what counts as a large capacity firearm or feeding device and what the Commonwealth must prove, including the defendant’s knowledge of the capacity. This page also covers the proof that the defendant had no license, 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. Attorney Serpa 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.” The definition also covers a set of parts from which a large capacity feeding device can be assembled, if one person possesses all of the parts. 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 semiautomatic firearm with a fixed large capacity feeding device. A large capacity firearm is also a semiautomatic firearm “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.” The definition 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. The definition excludes 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.

In St. 2024, c. 135, the Legislature added the words “when both are in the same person’s possession or under their control in a vehicle” to the definition of a large capacity firearm, effective October 2, 2024. Before October 2, 2024, a semiautomatic pistol that could accept a large capacity magazine was a large capacity weapon whether or not a large capacity magazine was present. For an offense on or after October 2, 2024, the Commonwealth must prove that the defendant possessed both the firearm and the detachable magazine, unless another part of the definition covers the firearm. No appellate court has yet interpreted 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 the object 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 the legal definition of a large capacity firearm or feeding device, or knew that the object 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.

The Commonwealth must also prove that a statutory exemption does not apply if the defendant offers some evidence that the exemption applies. The Superior Court’s model instruction on unlawful possession of a large capacity firearm or feeding device (July 14, 2026) lists the same elements.

The District Court has no model instruction for § 10(m), because the District Court cannot try a § 10(m) case. A violation of § 10(m) is punishable by up to ten years in state prison. Under G.L. c. 218, § 26, the District Court may try a felony punishable by more than five years only if § 26 lists the offense. Section 26 does not list § 10(m). The case begins with an arraignment in the District Court, but the Commonwealth must obtain an indictment and try the case 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 Supreme Judicial Court held that the evidence of knowledge 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 the magazine so as not to wear out the spring. The magazines were “noticeably larger” than a ten-round magazine. Cassidy, 479 Mass. at 537. The court held that the jury could infer knowledge from the defendant’s familiarity with his own weapons. Cassidy, 479 Mass. at 537-538.

The Appeals Court has reversed convictions because the Commonwealth did not prove knowledge. 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 the pistol, loaded with 14 rounds. The magazine did not stick out of the grip. The defendant said a friend had given him the gun. The Appeals Court held that the Commonwealth failed to prove knowledge. The court set aside the § 10(m) conviction and entered judgment for the defendant. Resende, 94 Mass. App. Ct. at 202-203.

In Commonwealth v. Cintron, No. 16-P-1698 (Mass. App. Ct. Dec. 28, 2018) (unpublished), the § 10(m) charge was 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 the gun. The Appeals Court reversed the § 10(m) conviction and entered judgment for the defendant, because the Commonwealth did not prove that the defendant knew the magazine could hold more than ten rounds.

The Commonwealth does not have 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 the juvenile had checked whether the gun was loaded and knew what the magazine held.

In Commonwealth v. Abdul-Alim, No. 24-P-178 (Mass. App. Ct. Jan. 17, 2025) (unpublished), the police found a 30-round rifle magazine with the defendant’s fingerprint on it in a bag he had told his wife to hide. The Appeals Court held that the evidence of knowledge was sufficient. In most § 10(m) cases, the jury decides whether to infer knowledge from the size of the magazine, who owned the gun, who loaded the gun, and what the defendant said about the gun.

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 that the defendant had no license. In Commonwealth v. Guardado, 491 Mass. 666 (2023), the Supreme Judicial Court held that the absence of a license is an element of the carrying and possession offenses under § 10(a) and § 10(h). The court declined to rule that the Second Amendment requires the same proof under § 10(m). Guardado, 491 Mass. at 693-694.

On reconsideration, the Supreme Judicial Court withdrew the part of its opinion about § 10(m). The court did not decide 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, because the statute itself applies only to a person without a license.

Under the statute, a firearm identification card is not a defense. The provision of § 10(m) that says an FID card is not a defense also says that a person who holds an FID card is not subject to the mandatory minimum sentence. “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 does not have to impose 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). Section 10(m) 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).” Under § 10(a) and § 10(h), the charge depends on whether the gun was inside or outside the home or business. Under § 10(m), the location of the gun makes no difference. A person with a large capacity pistol in a nightstand, in a car, or in a pocket faces the same § 10(m) charge. The residence exemption is a defense to a § 10(a) charge but not to a § 10(m) charge. The firm’s pages on carrying a firearm without a license and on possession without an FID card explain the § 10(a) and § 10(h) charges.

The court must set aside the § 10(a) conviction of a defendant who is convicted under both § 10(a) and § 10(m) for the same large capacity firearm. The § 10(a) crime is a lesser included offense of the § 10(m) crime, which means that the § 10(a) crime is part of the § 10(m) crime.

“The only difference between the two violations is the ‘capacity’ of the firearm.” Commonwealth v. Costa, 65 Mass. App. Ct. 227, 235 (2005). An appellate court reinstates the § 10(a) conviction if the court reverses the § 10(m) conviction because the Commonwealth did not prove that the defendant knew the gun or magazine could hold more than ten rounds. Resende, 94 Mass. App. Ct. at 202.

The Commonwealth may charge a separate count for each weapon and each feeding device. A defendant with one gun and three large capacity magazines faces four counts. Commonwealth v. Mazzantini, 74 Mass. App. Ct. 915 (2009). No appellate court has decided whether a defendant can be convicted separately for the firearm and for the magazine inside the firearm. Since October 2, 2024, the definition of a large capacity firearm has included the magazine in the same person’s possession. The defendant can therefore argue that a second count for the same magazine punishes the defendant twice for one magazine.

Penalties and the Sentence

The judge must sentence a defendant convicted under § 10(m) who did not hold a valid firearm identification card to state prison “for not less than two and one-half years nor more than ten years.” The Supreme Judicial Court has held that the maximum term must be at least two and one half years. 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 set aside sentences of one year to one year and a day.

The statute provides that 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. For an FID card holder, the Supreme Judicial Court has written that the judge’s sentencing choices presumably range from probation to ten years in state prison. Rodriguez, 482 Mass. at 368-369.

A judge cannot continue a § 10(m) case without a finding and cannot place the case on file, whether or not the defendant held an FID card. The statute states, “Prosecutions commenced under this subsection shall neither be continued without a finding nor placed on file.” A judge also may not order pretrial probation under G.L. c. 276, § 87 for any person 18 or older charged under § 10(m). Without a trial, a defendant can avoid a § 10(m) conviction only if the Commonwealth reduces or dismisses the charge.

The Commonwealth can ask a judge to hold the defendant without bail as dangerous on a § 10(m) charge, because G.L. c. 276, § 58A(1) names paragraph (m). Section 58A(1) also provides that 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.” The Commonwealth cannot ask a judge to hold a defendant without bail as dangerous on a charge involving only a magazine. 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 a longer sentence under the armed career criminal statute, § 10G. The firm’s firearms defense page explains § 10G. 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, § 131M has provided 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 possession of that item. G.L. c. 140, § 131(a).

Section 131M contains two exceptions for items that owners already had. A license holder who lawfully possessed an assault-style firearm in Massachusetts on August 1, 2024 may keep the firearm if it is registered under § 121B and serialized under § 121C. A person who lawfully possessed a large capacity feeding device on September 13, 1994 may keep the device only in five places. The owner may keep the device on the owner’s own property, on private property with the owner’s permission, at a dealer or gunsmith for repair, or at a licensed range or competition. The owner may also have the device while traveling to or from any place where the owner may keep the device, if the device is unloaded and locked. G.L. c. 140, § 131M(b), (c).

The possible penalties for a defendant convicted under § 131M of a first offense 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 the definitions of a large capacity firearm and a large capacity feeding device, and § 131M. A no vote would repeal the act. This page states the law in effect on the date the page 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. The court reasoned that 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 did not decide whether large capacity feeding devices are protected arms. Guardado, 493 Mass. at 4 n.2.

In Capen v. Campbell, 134 F.4th 660 (1st Cir. 2025), the United States Court of Appeals for the First Circuit refused to stop Massachusetts officials from enforcing the ban under the earlier statute. In Recchia v. Campbell, No. 25-1817 (1st Cir. July 21, 2026), the First Circuit again refused to stop Massachusetts officials from enforcing the ban under the 2024 act. No court has ordered Massachusetts officials to stop enforcing any provision of § 10(m) or § 131M. A defendant who wants to argue on appeal that § 10(m) violates the Second Amendment must first raise the Second Amendment argument in a 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. In Resende, the magazine sat flush inside the grip. In Cintron, the defendant had received the gun only days before and had never fired the gun.

Possession. In a car with several people in it or a shared apartment, the Commonwealth must prove that the defendant knew the gun was there and had both the ability and the intention to control the gun. The constructive possession rules described on the § 10(a) page apply.

The definition. Defense counsel examines whether the firearm is semiautomatic. For an offense on or after October 2, 2024, counsel also examines whether a magazine holding more than ten rounds was in the defendant’s possession along with the firearm. Counsel then considers whether the statute excludes the device. The statute excludes, for example, 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. Defense counsel also insists that the Commonwealth prove that the defendant had no license. The Supreme Judicial Court did not decide in Guardado whether the Second Amendment protects large capacity feeding devices. Defense counsel argues in the trial court that the Second Amendment protects large capacity feeding devices, so that the defendant can raise the argument on appeal.

Suppression. Most § 10(m) cases begin with a car stop or a search. The judge suppresses the gun and the magazine if the stop, the exit order, the frisk, or the entry was unlawful. The Commonwealth cannot use a suppressed gun or magazine as evidence. The firm’s pages on illegal searches and seizures, and on traffic stops and exit orders, explain the motions.

Two convictions for the same gun. The court must set aside the § 10(a) conviction of a defendant convicted under § 10(a) and § 10(m) for the same firearm, because the § 10(a) crime is part of the § 10(m) crime. 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. Defense counsel therefore 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. Under G.L. c. 140, § 121F(j), a person convicted under § 10(m) can never hold a license to carry or a firearm identification card. 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 noncitizen convicted under § 10(m) of possessing a large capacity firearm is also deportable under 8 U.S.C. § 1227(a)(2)(C), because possessing a large capacity firearm is a firearms offense. No court has decided whether a conviction based only on a magazine makes a noncitizen deportable under § 1227(a)(2)(C). An immigration lawyer should review the exact charge, the client’s immigration status, and the court record before any plea. The immigration lawyer should also review the record before the client files a petition or sits for an interview, where an officer may ask about the arrest or the police report. The firm’s immigration consequences pages explain how an immigration lawyer reviews a criminal case.

After arraignment, the charge appears on the defendant’s criminal record. The Commissioner of Probation can seal a § 10(m) conviction under G.L. c. 276, § 100A, seven years after the case ends and after any time in custody, if the person has no new conviction during the seven-year waiting period. A judge can seal a dismissal under § 100C with no waiting period.

Attorney Serpa’s Representation in Large Capacity Cases

Attorney Joe Serpa has practiced Massachusetts criminal defense since 1995. Attorney Serpa defends § 10(m) charges from the District Court arraignment through the Superior Court. In some cases, the police bring a § 10(m) charge together with a charge of carrying a firearm without a license. In other cases, the police bring a § 10(m) charge by itself after a search of a home. In every § 10(m) case, Attorney Serpa 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.

Attorney Serpa then advises the client on a motion to suppress, a motion asking the judge to find the client not guilty, a trial, or a negotiated reduction of the charge. In the motion asking the judge to find the client not guilty, Attorney Serpa argues that the Commonwealth did not prove that the client knew the magazine could hold more than ten rounds.

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
• Carrying a Loaded Gun During an OUI Stop or While Drunk in Massachusetts Under G.L. c. 269, § 10H
• Untraceable Firearms, Ghost Guns, and Defaced Serial Numbers in Massachusetts: G.L. c. 269, § 11C
• 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