1929 Pa. Laws 777, An Act prohibiting the sale, giving away, transfer, purchasing, owning, possession and use of machine guns: § 3.

§ 3. Any person who shall commit, or attempt to commit, any crime within this Commonwealth, when armed with a machine gun, shall upon conviction of such crime or attempt to commit such crime, in addition to the punishment for the crime for which he has been convicted, be sentenced to separate and solitary confinement at labor for a term not exceeding ten years. Such additional penalty of imprisonment shall commence upon the expiration or termination of the sentence imposed for the crime of which he stands convicted, and shall not run concurrently with such sentence.