C.R.S. § 18-12-118: Unlawful three-dimensional printing of a firearm or firearm component - penalties - definitions.

(1) (a) A person shall not knowingly manufacture or produce a firearm or firearm component by means of three-dimensional printing using a three-dimensional printer, CNC milling machine, or similar device.

(b) A person who violates this subsection (1) commits unlawful three-dimensional printing of a firearm or firearm component. Unlawful three-dimensional printing of a firearm or firearm component is a class 1 misdemeanor; except that a second or subsequent offense is a class 5 felony.

(c) This subsection (1) does not apply to:

(I) A federally licensed firearm manufacturer;

(II) An instructor or student of an accredited gunsmithing program, or an institution that operates an accredited gunsmithing program, when the manufacture is solely for purposes of educational instruction within the accredited gunsmithing program.

(2) This section only applies to potentially functional firearms and firearm components and does not apply to the three-dimensional printing of any other components or components that could be used to make a non-functioning or prop firearm.

(3) As used in this section, unless the context otherwise requires:

(a) "CNC milling machine" means a computer numerical control milling machine.

(b) "Firearm component" means an unfinished frame or receiver, large-capacity magazine, or rapid-fire device.

(c) "Gunsmithing program" means a gunsmithing program operated by an institution.

(d) "Institution" means a state-authorized institution of higher education or institution regulated by the Colorado division of private occupational schools.

(e) "Large-capacity magazine" has the same meaning set forth in section 18-12-301.

(f) "Three-dimensional printing" or "3-D printing" means additive manufacturing that builds three-dimensional objects by use of a three-dimensional printer or similar device and subtractive manufacturing that creates objects by removing material from a workpiece by use of a CNC milling machine or similar device.