Brookline gun owners must register their firearms through a state online portal by Wednesday, Oct. 28, or face penalties that range from a $1,000 fine to prison time.
The Brookline Police Department posted the warning on X on Thursday, Sept. 24, citing Chapter 135 of the Acts of 2024, the Act Modernizing Firearm Laws. The department said the state law significantly expanded registration requirements for gun owners.
Governor Maura Healey signed an emergency preamble on Oct. 2, 2024, putting the law into immediate effect, according to the Congressional Sportsmen's Foundation. The law broadened the legal definition of "firearm" to include frames, receivers and unfinished frames or receivers.
What gun owners need to do
The state's FAQ page confirms Oct. 28 as the deadline to register and serialize firearms through the MIRCS Unified Gun Portal, the state's electronic registration system. Gun owners need a MyMassGov account to access the portal.
One exception: firearms purchased from a licensed Massachusetts dealer do not need to be re-registered. The dealer reports those transactions. Any firearm previously recorded through the old FA-10 transaction system also does not need a new entry.
Owners of firearms without serial numbers face an additional step. They must request a unique serial number from the Department of Criminal Justice Information Services (DCJIS) through the portal, then have it permanently engraved to a depth of at least .003 inches and a print size of at least one-sixteenth of an inch, according to attorney Joe Serpa's legal analysis of the implementing regulations.
Serpa's analysis flags a possible earlier deadline. The regulation implementing the serialization requirement, 501 CMR 20.00, may set Friday, Oct. 2, as the cutoff for unserialized firearms. The state's own guidance documents are inconsistent on this point. Gun owners with unserialized firearms should contact DCJIS or a firearms attorney to confirm their deadline.
Penalties
Missing the deadline carries escalating penalties under state law. A first registration violation carries a fine of up to $1,000, according to Serpa's analysis. A second offense can mean up to $7,500 in fines or up to six months in jail. A third or subsequent offense is punishable by a fine of up to $10,000 and one to five years in prison. The state can also suspend or permanently revoke a violator's firearms license.
Ballot question on repeal
Voters will decide whether to repeal Chapter 135 on Nov. 3 as Question 9 on the ballot. But both compliance deadlines fall before Election Day.
"Waiting for November is not a compliance strategy, because both deadlines fall before the election," Serpa wrote in a May 2026 analysis of the law.
Brookline residents who need a new license to carry or firearms identification card apply through the Brookline Police Department, according to the state FAQ.
