1. Short title This Act may be cited as the Protecting the Second Amendment through Responsible Gun Ownership Act . 2. Prohibition on purchase of a semiautomatic assault weapon by, and sale of such a weapon to, individuals under 25 years of age (a) Definitions Section 921(a) of title 18, United States Code, is amended— (1) by inserting after paragraph (30) the following: (31) The term semiautomatic assault weapon means any of the following, regardless of country of manufacture or caliber of ammunition accepted: (A) A semiautomatic rifle that has the capacity to accept a detachable ammunition feeding device and any one of the following: (i) A pistol grip. (ii) A forward grip. (iii) A folding, telescoping, or detachable stock, or is otherwise foldable or adjustable in a manner that operates to reduce the length, size, or any other dimension, or otherwise enhances the concealability, of the weapon. (iv) A grenade launcher. (v) A barrel shroud. (vi) A threaded barrel. (B) A semiautomatic rifle that has a fixed ammunition feeding device with the capacity to accept more than 10 rounds, except for an attached tubular device designed to accept, and capable of operating only with, .22 caliber rimfire ammunition. (C) Any part, combination of parts, component, device, attachment, or accessory that is designed or functions to accelerate the rate of fire of a semiautomatic rifle but not convert the semiautomatic rifle into a machinegun. (D) A semiautomatic pistol that has the capacity to accept a detachable ammunition feeding device and any one of the following: (i) A threaded barrel. (ii) A second pistol grip. (iii) A barrel shroud. (iv) The capacity to accept a detachable ammunition feeding device at some location outside of the pistol grip. (v) A semiautomatic version of an automatic firearm. (vi) A manufactured weight of 50 ounces or more when unloaded. (vii) A stabilizing brace or similar component. (E) A semiautomatic pistol with a fixed ammunition feeding device that has the capacity to accept more than 10 rounds. (F)