Assemble. To fit together a firearm's component parts; provided, however, that "assemble" shall not include firearms reassembly, repair of the fitting of special barrels, stocks, or trigger mechanisms to firearms, as defined in M.G.L. c. 140, § 121.

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 firearms defined in M.G.L. c. 140, § 121.

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, as defined in M.G.L. c. 140, § 121.

Individual: A natural person.

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, as defined in M.G.L. c. 140, § 121.

Massachusetts Instant Record Check System (MIRCS). The automated system operated and maintained by the DCJIS that provides on-line firearms licensing by licensing authorities and on-line reporting of gun transactions by gun dealers and private parties.

MIRCS Firearms Licensing Portal (MIRCS portal). The web-based system that allows users to electronically submit information to and/or request information from the DCJIS via the MIRCS. The MIRCS portal may be used to submit a firearms license application, check the status of a firearms license application, report a name or address change, obtain a firearms license PIN, request a unique firearms serial number, and register a firearm.

Nonresident. A person who is temporarily in the commonwealth but legally resides in another state or territory of the United States, as defined in M.G.L. c. 140, § 121.

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 person licensed under M.G.L. c. 140, § 122 in the course of their business activities, as defined in M.G.L. c. 140, § 121.

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, as defined in M.G.L. c. 140, § 121.

Requestor. Individual, entity, or manufacturer requesting a unique serial number from DCJIS via the MIRCS portal.

Unfinished Frame or Receiver. A forging, casting, printing, extrusion, machined body or similar item that:

1. (a) has reached a stage in manufacture when it may readily be completed or assembled to function as a frame or receiver; or
2. (b) is marketed or sold to the public to become or be used as the frame or receiver of a functional firearm once completed or assembled; provided, however, that "unfinished frame or receiver" shall not include a component designed and intended for use in an antique firearm.

Valid Serial Number. An identifying number that has been:

1. (a) placed on a firearm by a federally licensee authorized to serialize firearms or pursuant to the laws of any state or 26 U.S.C. 5842 and the regulations promulgated thereunder; or
2. (b) a serial number issued by the director of the Bureau of Alcohol, Tobacco, Firearms and Explosives in the United States Department of Justice or the department of criminal justice information services.

Unique Serial Number. A serial number issued by DCJIS via the MIRCS portal in compliance with 501 CMR 19.00.