Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 140, § 121D

(a) 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 under section 131.

(b) No person shall sell, offer to sell or transfer a 3-dimensional printer or computer numerical control milling machine that has the primary or intended function of manufacturing or assembling firearms to any person in the commonwealth. A 3-dimensional printer or computer numerical milling machine has the primary or intended function of manufacturing or assembling firearms if the printer or machine is advertised, marketed or promoted to manufacture or assemble firearms, regardless of whether the printer or machine is otherwise described or classified as having other functions or as a general-purpose printer or machine.

(c) This section shall not apply to 3-dimensional printers or computer numerical control milling machines that are: (i) possessed by a forensic laboratory; (ii) being delivered to law enforcement for the sole purpose of their destruction; (iii) possessed by common carriers and their duly authorized employees and agents while performing the regular and ordinary transport of firearms as merchandise for customers licensed to permit such transport; (iv) possessed by or sold to a federally licensed manufacturer of firearms; or (v) the property of the government of the United States.

(d) A violation of this section shall be punishable by imprisonment for not more than 1 year or by a fine of not more than $5,000 per firearm per violation or both such fine and imprisonment.