Dennis police went to a home on Cape Cod last week looking into a report that a juvenile had pointed a handgun at someone. With a search warrant, detectives found something bigger: multiple unfinished or partially assembled handguns with homemade frames and slides, magazines, triggers, springs, firearm assembly tools, laptops, and a 3D printer with numerous rolls of filament, according to the Dennis Police Department, as reported by the Fall River Reporter. Boston 25 News also reported that ghost gun materials were found in the home.
“This case shows how quickly and quietly these tools can make their way into a home,” Dennis Police Chief Brady said, urging parents to pay attention to what packages arrive and “what equipment, like 3D printers, is being used behind closed doors.” Charges will be sought with the Cape and Islands District Attorney’s Office, police said, and because of the person’s age no identifying information was released. The juvenile is presumed innocent.
Several of the Massachusetts laws that apply to homemade and 3D-printed guns are new. They were added by Chapter 135 of the Acts of 2024, the gun law that is on the November 3 ballot as Question 9. Here is what those laws say.
Using a 3D printer to make a gun: G.L. c. 140, § 121D
Chapter 135 created a specific crime for 3D-printed and machined guns:
- “No person shall use a 3-dimensional printer or computer numerical control milling machine to manufacture or assemble any firearm within the commonwealth without a valid license to carry firearms.” § 121D(a).
- It is also illegal to sell or transfer a 3D printer or CNC milling machine “that has the primary or intended function of manufacturing or assembling firearms” to anyone in Massachusetts. A machine counts if it is “advertised, marketed or promoted” for making guns, even if it is described as general-purpose. § 121D(b).
- The penalty is up to one year in jail, a fine of up to $5,000 per firearm per violation, or both. § 121D(d).
Owning an ordinary 3D printer is not a crime. The offense is using one to make a firearm without a license to carry, or selling one marketed for that purpose.
Untraceable firearms: G.L. c. 269, § 11C
Chapter 135 also rewrote the state’s untraceable firearm statute. Under the current § 11C, anyone who “knowingly manufactures, assembles, imports, sells or transfers ownership of an untraceable firearm,” or knowingly participates in doing so, or “purchases or receives a firearm with knowledge that it is untraceable,” faces imprisonment for not less than 12 months and not more than two and a half years.
The statute adds a presumption: “Possession or control of a firearm that is untraceable shall be prima facie evidence” of a violation, though the defendant may rebut it with evidence that they “had no knowledge that the firearm was untraceable.”
State law defines an “untraceable firearm” as “a firearm that has not been serialized or a firearm whose serial or other identification number has been removed, defaced, altered, obliterated or mutilated in any manner.” G.L. c. 140, § 121.
Homemade guns must be serialized and registered
Massachusetts now requires every gun in the state to be registered in an electronic system run by the Department of Criminal Justice Information Services. G.L. c. 140, § 121B. A privately made firearm must be registered “within 7 days if manufactured or assembled.” Failing to register is punishable by a fine of up to $1,000 for a first offense, rising to up to $10,000 or one to five years in prison, or both, for a third or later offense.
What happens with a juvenile
Police have not released the juvenile’s name or age. What specific charges will be brought has not been announced. The report that the juvenile pointed a handgun at someone is a separate allegation from the gun-making materials, and could support its own charges.
Question 9 and these laws
Question 9 asks voters whether to keep Chapter 135. A yes vote keeps the law in effect; a no vote repeals it. The 3D-printer crime in § 121D and the current text of the untraceable-firearm statute in § 11C were both enacted by Chapter 135. Our Question 9 explainer covers what else the law does and the arguments on each side.
Frequently asked questions
Is it illegal to 3D print a gun in Massachusetts?
Yes, without a valid license to carry. G.L. c. 140, section 121D makes it a crime to use a 3D printer or CNC milling machine to manufacture or assemble a firearm without one, punishable by up to one year in jail and a fine of up to $5,000 per firearm.
What is the penalty for an untraceable firearm in Massachusetts?
Under G.L. c. 269, section 11C, knowingly making, assembling, selling, transferring or receiving an untraceable firearm is punishable by 12 months to two and a half years in jail.
Do homemade guns have to be registered in Massachusetts?
Yes. A privately made firearm must be registered in the state’s electronic firearms registration system within 7 days of being manufactured or assembled. G.L. c. 140, section 121B.
Would Question 9 repeal the 3D-printed gun law?
Section 121D was created by Chapter 135 of the Acts of 2024, the law on the ballot as Question 9. A no vote on Question 9 repeals Chapter 135; a yes vote keeps it.
Sources: Fall River Reporter, October 2026, reporting a Dennis Police Department statement; Boston 25 News, October 8, 2026. G.L. c. 140, sections 121, 121B and 121D, and G.L. c. 269, section 11C, read at malegislature.gov; Chapter 135 of the Acts of 2024 read at malegislature.gov. The juvenile has not been charged and is presumed innocent. General information about Massachusetts law, not legal advice.