In sections one hundred and twenty-two to one hundred and twenty-nine, inclusive, “firearms” includes a pistol, revolver or other weapon of any description, loaded or unloaded, from which a shot or bullet can be discharged and of which the length of barrel, not including any revolving, detachable or magazine breach, does not exceed twelve inches, and a machine gun, irrespective of the length of the barrel. Any gun of small arm calibre designed for rapid fire and operated by a mechanism, or any gun which operates automatically after the first shot has been fired, either by gas action or recoil action, shall be deemed to be a machine gun for the purposes of said sections, and of sections one hundred and thirty–one and one hundred and thirty one B. . . § 2. . . Eighth, That no pistol or revolver shall be sold, rented or leased to a person who has not a permit, then in force, to purchase, rent or lease the same issued under section one hundred and thirty-one A, and that no machine gun shall be sold, rented or leased to a person who has not a license to possess the same issued under section one hundred and thirty-one. . .