1919 Colo. Sess. Laws 416–417, Foreign-Born Unnaturalized Citizens, § 1.

. . . [I]t shall be unlawful for any unnaturalized foreign-born resident to hunt for or capture or kill, in this state; any wild bird or animal, either game or otherwise, of any description, excepting in defense of persons or property; and to that end it shall be unlawful for any unnaturalized foreign-born resident, within this state, to either own or be possessed of a shotgun or rifle of any make, or a pistol or firearm of any kind. Each and every person violating any provisions of this section shall be guilty of a misdemeanor, and, upon conviction thereof, shall be punished by a fine of not less than twenty five dollars ($25) nor more than two hundred and fifty dollars ($250), or by imprisonment in the county jail not less than ten (10) days or more than three months (3), or by both such fine and imprisonment. Provided, that in addition the before-named penalty all guns of the above mentioned kinds found in possession or under control of an unnaturalized foreign-born resident shall, upon conviction of such person, be declared forfeited to the State of Colorado . . . .