C.R.S. § 18-12-303

(1) A large-capacity magazine that is manufactured in Colorado on or after July 1, 2013, must include a permanent stamp or marking indicating that the large-capacity magazine was manufactured or assembled after July 1, 2013. The stamp or marking must be legibly and conspicuously engraved or cast upon the outer surface of the large-capacity magazine. (2) The bureau may promulgate such rules as may be necessary for the implementation of this section, including but not limited to rules requiring a large-capacity magazine that is manufactured on or after July 1, 2013, to bear identifying information in addition to the identifying information described in subsection (1) of this section. (3) A person who manufactures a large-capacity magazine in Colorado in violation of subsection (1) of this section commits a class 2 misdemeanor and shall be punished in accordance with section 18-1.3-501 .