§ 1. Definitions. (a) Any firearm capable of loading or firing automatically, the magazine of which is capable of holding more than twelve cartridges, shall be a machine gun within the provisions of the Act. (b) Any firearm capable of automatically reloading after each shot is fired, whether firing singly by separate trigger pressure or firing continuously by continuous trigger pressure; which said firearm shall have been changed, altered or modified to increase the magazine from the original design as manufactured by the manufacturers thereof, or by the addition thereto of extra and/or longer grips or stocks to accommodate such extra capacity, or by the addition, modification and/or attachment thereto of any other device capable of increasing the magazine capacity thereof, shall be a machine gun within the provisions of this Act. (c) A twenty-two caliber light sporting rifle, capable of firing continuously by continuous trigger pressure, shall be a machine gun within the provisions of this Act. But a twenty-two caliber light sporting rifle, capable of automatically reloading but firing separately by separate trigger pressure for each shot, shall not be a machine gun within the provisions of this Act and shall not be prohibited hereunder, whether having a magazine capacity of twelve cartridges or more. But if the same shall have been changed, altered, or modified, as prohibited in section one (b) hereof, then the same shall be a machine gun within the provisions of this Act. § 2. Application. This Act shall not apply to sheriffs, coroners, constables, policemen or other peace officers, or to any warden, superintendent or head keeper of any prison, penitentiary, county jail or other institution for retention of any person convicted or accused of crime, while engaged in the discharge of official duties, or to any public official engaged in the enforcement of law; nor to any person or association possessing a machine gun not usable as a weapon and possessed as a curiosity, ornament or keepsake; when such officers and persons and associations so excepted shall make and file with the Bureau of Criminal Apprehension of this state within 30 days after the passage of this Act, a written report showing the name and address of such person or association and the official title and position of such officers . . . § 3. Machine guns prohibited. Any person who shall own, control, use, possess, sell or transport a machine gun, as herein defined, in violation of this Act, shall be guilty of a felony.