Mass. Gen. Laws ch. 140 § 121
As used in sections 122 to 131Y, inclusive, the following words shall, unless the context clearly requires otherwise, have the following meanings:
"Ammunition", cartridges or cartridge cases, primers (igniter), bullets or propellant powder designed for use in any firearm, rifle or shotgun. The term "ammunition" shall also mean tear gas cartridges.
"Antique firearm", any firearm or replica thereof manufactured in or prior to the year 1899 if such firearm:
"Assault-style firearm", any firearm which is:
"Assemble", to fit together a firearm's component parts; provided, however, that "assemble" shall not include firearm reassembly, repair or the fitting of special barrels, stocks or trigger mechanisms to firearms.
"Automatic conversion", any modification made to a firearm, including through the use of an automatic part, that allows for the automatic discharge of more than 1 shot with 1 continuous activation of the trigger or that alters or increases the rate of fire to mimic automatic fire.
"Automatic part", any device, part or combination of parts capable of being attached to a firearm that allows for the automatic discharge of more than 1 shot with 1 continuous activation of the trigger or that increases the rate of fire of a firearm to mimic automatic fire.
"Bona fide collector of firearms", a licensed collector pursuant to 18 U.S.C. section 923(b).
"Bump stock", any device for a weapon that increases the rate of fire achievable with such weapon by using energy from the recoil of the weapon to generate a reciprocating action that facilitates repeated activation of the trigger.
"Conviction", a finding or verdict of guilt or a plea of guilty, whether or not final sentence is imposed.
"Court", as used in sections 131R to 131Y, inclusive, the division of the district court department or the Boston municipal court department of the trial court having jurisdiction in the city or town in which the respondent resides.
"Covert firearm", a firearm placed in a camouflaging firearm container, or a firearm that is not a stun gun, that is capable of discharging a bullet or shot and is constructed in a shape that does not resemble a firearm or is not immediately recognizable as a firearm, including, but not limited to, zip guns, concealed bolt guns, folding guns and any other firearm that resemble key-chains, pens, canes, wallets, flashlights, cigarette-lighters or cigarette-packages, flare guns, pellet guns and bb gun conversion kits.
"Curio or relic firearms", firearms which are of special interest to collectors because they possess some qualities not ordinarily associated with firearms intended for sporting use or as offensive or defensive firearms.
"Deceptive weapon device", any device that is intended to convey the presence of a rifle, shotgun or firearm that is used in the commission of a violent crime, as defined in this section, and which presents an objective threat of immediate death or serious bodily harm to a person of reasonable and average sensibility.
"Deceptive firearm device", any device that is intended to convey the presence of a firearm that is used in the commission of a violent crime and that presents an objective threat of immediate death or serious bodily harm to a person of reasonable and average sensibility.
"Extreme risk protection order", an order by the court that orders:
"Family or household member", a person who:
"Feeding device", any magazine, belt, strip, drum or similar device that holds ammunition for a firearm, whether fixed or detachable from a firearm.
"Firearm", a stun gun, pistol, revolver, rifle, shotgun, sawed-off shotgun, large capacity firearm, assault-style firearm and machine gun, loaded or unloaded, which is designed to or may readily be converted to expel a shot or bullet; the frame or receiver of any such firearm or the unfinished frame or receiver of any such firearm; provided, however, that "firearm" shall not include any antique firearm or permanently inoperable firearm.
"Frame", the part of a pistol or revolver that provides housing or a structure for the component designed to hold back the hammer, striker, bolt or similar primary energized component prior to initiation of the firing sequence, even if pins or other attachments are required to connect such component to the housing or structure. Any such part that is identified with an importer or manufacturer serial number shall be presumed, absent an official determination by the Bureau of Alcohol, Tobacco, Firearms and Explosives in the United States Department of Justice or other reliable evidence to the contrary, to be the frame of the firearm.
"Gunsmith", any person who engages in the business of repairing, altering, cleaning, polishing, engraving, blueing or performing any mechanical operation on any firearm.
"Imitation firearm", any firearm which is designed, manufactured or altered in such a way as to render it incapable of discharging a shot or bullet.
"Large capacity feeding device", (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:
"Large capacity firearm", any firearm that:
"Licensing authority", the chief of police or the board or officer having control of the police in a city or town, or persons authorized by them; provided, however, that should no such chief or officer exist the colonel of the state police or their designee shall act as the licensing authority.
"Machine gun", a firearm, loaded or unloaded, which may automatically discharge more than 1 shot by a continuous activation of the trigger, whether originally manufactured as such or modified by automatic conversion, including through the use of an automatic part or any firearm, loaded or unloaded, which has been modified by automatic conversion to alter or increase its rate of fire to mimic automatic fire; provided, however, that "machine gun" shall include a submachine gun.
"Manufacture", to fabricate, make, form, produce or construct, by manual labor or by machinery, a firearm; provided, however, that "manufacture" shall not include firearm reassembly, firearm repair or the making or fitting of special barrels, stocks or trigger mechanisms to firearms.
"Nonresident", a person who is temporarily in the commonwealth but legally resides in another state or territory of the United States.
"Permanently embedded", applied in such a way that cannot be easily or readily removed without destroying the part to which it is applied.
"Petition", as used in sections 131R to 131Y, inclusive, a request filed with the court by a petitioner for the issuance or renewal of an extreme risk protection order.
"Petitioner", as used in sections 131R to 131Y, inclusive, the individual that is filing the petition and is:
"Privately made firearm", a firearm manufactured or assembled by an individual who is not a licensed manufacturer; provided, however, that "privately made firearm" shall not include firearms manufactured or assembled by persons licensed under section 122 in the course of their business activities.
"Purchase" and "sale" shall include exchange; the word "purchaser" shall include exchanger; and the verbs "sell" and "purchase", in their different forms and tenses, shall include the verb exchange in its appropriate form and tense.
"Rapid-fire trigger activator", any:
"Receiver", the part of a rifle or shotgun that provides housing or a structure for the primary component designed to block or seal the breech prior to initiation of the firing sequence, even if pins or other attachments are required to connect such component to the housing or structure. Any such part that is identified with an importer or manufacturer serial number shall be presumed, absent an official determination by the Bureau of Alcohol, Tobacco, Firearms and Explosives in the United States Department of Justice or other reliable evidence to the contrary, to be the receiver of the firearm.
"Respondent", as used in sections 131R to 131Y, inclusive, the person identified as the respondent in a petition against whom an extreme risk protection order is sought.
"Rifle", a firearm having a rifled bore with a barrel length equal to or greater than 16 inches and capable of discharging a shot or bullet for each pull of the trigger.
"Sawed-off shotgun", any firearm made from a shotgun, whether by alteration, modification or otherwise, if such firearm as modified has one or more barrels less than 18 inches in length or as modified has an overall length of less than 26 inches.
"Secured in a locked container", secured in a container that is capable of being unlocked only by means of a key, combination or similar means, including in an unoccupied motor vehicle, a locked trunk not accessible from the passenger compartment, a locked console or locked glovebox and for purposes of a common carrier in the course of the regular and ordinary transport of firearms, locked access to any area containing firearms.
"Self-defense spray", chemical mace, pepper spray or any device or instrument which contains, propels or emits a liquid, gas, powder or other substance designed to incapacitate.
"Semiautomatic", capable of utilizing a portion of the energy of a firing cartridge to extract the fired cartridge case and chamber the next round, and requiring a separate pull of the trigger to fire each cartridge.
"Serialization", the process of conspicuously engraving, casting or otherwise permanently embedding a unique serial number on a firearm frame or receiver; provided, that the serial number shall be placed in a manner not susceptible to being readily obliterated, altered or removed and shall be engraved, cast or otherwise permanently embedded to a depth of not less than .003 inches and in a print size not less than 1/16 inch; and provided further, that serialization of firearms, frames and receivers made from non-metallic materials shall be accomplished by using a metal plate permanently embedded in the material of the frame or receiver.
"Shotgun", a firearm having a smooth bore with a barrel length equal to or greater than 18 inches with an overall length equal to or greater than 26 inches, and capable of discharging a shot or bullet for each pull of the trigger.
"Stun gun", a portable device or weapon, regardless of whether it passes an electrical shock by means of a dart or projectile via a wire lead, from which an electrical current, impulse, wave or beam that is designed to incapacitate temporarily, injure or kill may be directed.
"Substantive dating relationship", a relationship as determined by the court after consideration of the following factors:
"Trigger modifier", any modification that repeatedly activates the trigger of a firearm, including, but not limited to, trigger cranks, binary triggers and hellfire triggers.
"Undetectable firearm", (i) a firearm that after the 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 (ii) 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.
"Unfinished frame or receiver", a forging, casting, printing, extrusion, machined body or similar item that:
"Untraceable firearm", 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.
"Valid serial number", an identifying number that has been:
"Violent crime", shall mean any crime punishable by imprisonment for a term exceeding one year, or any act of juvenile delinquency involving the use or possession of a deadly weapon that would be punishable by imprisonment for such term if committed by an adult, that: (i) has as an element the use, attempted use or threatened use of physical force or a deadly weapon against the person of another; (ii) is burglary, extortion, arson or kidnapping; (iii) involves the use of explosives; or (iv) otherwise involves conduct that presents a serious risk of physical injury to another.
Mass. Gen. Laws ch. 140, § 140:121