This Act may be cited as the “Age 21 Act”.

(a) Definitions.—Section 921(a) of title 18, United States Code, is amended—

(1) by inserting after paragraph (29) the following:

“(30) The term ‘semiautomatic pistol’ means any repeating pistol that—

“(A) utilizes a portion of the energy of a firing cartridge to extract the fired cartridge case and chamber the next round; and

“(B) requires a separate pull of the trigger to fire each cartridge.

“(31) The term ‘semiautomatic shotgun’ means any repeating shotgun that—

“(A) utilizes a portion of the energy of a firing cartridge to extract the fired cartridge case and chamber the next round; and

“(B) requires a separate pull of the trigger to fire each cartridge.”; and

(2) by adding at the end the following:

“(36) 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 magazine and any one of the following:

“(i) A pistol grip.

“(ii) A forward grip.

“(iii) A folding, telescoping, or detachable stock.

“(iv) A grenade launcher or rocket launcher.

“(v) A barrel shroud.

“(vi) A threaded barrel.

“(B) A semiautomatic rifle that has a fixed magazine with the capacity to accept more than 10 rounds, except for an attached tubular device designed to accept, and is 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 magazine 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 magazine at some location outside of the pistol grip.

“(E) A semiautomatic version of an automatic firearm.

“(F) A semiautomatic pistol with a fixed magazine that has the capacity to accept more than 10 rounds.

“(G) A semiautomatic shotgun that has any one of the following:

“(i) A folding, telescoping, or detachable stock.

“(ii) A pistol grip.

“(iii) A fixed magazine with the capacity to accept more than 5 rounds.

“(iv) The ability to accept a detachable magazine.

“(v) A forward grip.

“(vi) A grenade launcher or rocket launcher.

“(H) Any shotgun with a revolving cylinder.

“(I) All belt-fed semiautomatic firearms.

“(J) Any combination of parts from which a firearm described in subparagraphs (A) through (I) can be assembled.

“(K) The frame or receiver of a rifle or shotgun described in subparagraph (A), (B), (C), (E), (G), (H), or (I).

“(37) The term ‘large capacity ammunition feeding device’—

“(A) means a magazine, belt, drum, feed strip, or similar device, including any such device joined or coupled with another in any manner, that has an overall capacity of, or that can be readily restored, changed, or converted to accept, more than 10 rounds of ammunition; and

“(B) does not include an attached tubular device designed to accept, and be capable of operating only with, .22 caliber rimfire ammunition.

“(38) The term ‘barrel shroud’—

“(A) means a shroud that is attached to, or partially or completely encircles, the barrel of a firearm so that the shroud protects the user of the firearm from heat generated by the barrel; and

“(B) does not include—

“(i) a slide that partially or completely encloses the barrel; or

“(ii) an extension of the stock along the bottom of the barrel which does not encircle or substantially encircle the barrel.

“(39) The term ‘detachable magazine’ means an ammunition feeding device that can be removed from a firearm without disassembly of the firearm action.

“(40) The term ‘fixed magazine’ means an ammunition feeding device that is permanently fixed to the firearm in such a manner that it cannot be removed without disassembly of the firearm.

“(41) The term ‘folding, telescoping, or detachable stock’ means a stock that folds, telescopes, detaches or otherwise operates to reduce the length, size, or any other dimension, or otherwise enhances the concealability, of a firearm.

“(42) The term ‘forward grip’ means a grip located forward of the trigger that functions as a pistol grip.

“(43) The term ‘rocket’ means any simple or complex tubelike device containing combustibles that on being ignited liberate gases whose action propels the tube through the air and has a propellant charge of not more than 4 ounces.

“(44) The term ‘grenade launcher or rocket launcher’ means an attachment for use on a firearm that is designed to propel a grenade, rocket, or other similar destructive device.

“(45) The term ‘pistol grip’ means, with respect to a shotgun or rifle, a pistol style grip, including a thumbhole stock or any other characteristic that can function as a pistol style grip.

“(46) The term ‘threaded barrel’ means a feature or characteristic that is designed in such a manner to allow for the attachment of a device such as a firearm silencer or a flash suppressor.

“(47) The term ‘belt-fed semiautomatic firearm’ means any repeating firearm that—

“(A) utilizes a portion of the energy of a firing cartridge to extract the fired cartridge case and chamber the next round;

“(B) requires a separate pull of the trigger to fire each cartridge; and

“(C) has the capacity to accept a belt ammunition feeding device.”.

(b) Prohibition.—Chapter 44 of title 18, United States Code, is amended—

(1) in section 922—

(A) in subsection (b)—

(i) in paragraph (1)—

(I) by inserting “(A)” after “(1)”; and

(II) by inserting “or” after the semicolon; and

(ii) by adding at the end the following:

“(B) any large capacity ammunition feeding device to any individual who the licensee knows or has reasonable cause to believe is less than 21 years of age;”;

(B) in subsection (c)(1), by inserting “a large capacity ammunition feeding device or” before “any firearm other than”; and

(C) in subsection (x)—

(i) in paragraph (1), by striking “a juvenile—” and all that follows through “handgun.” and inserting the following: “less than 21 years of age—

“(A) a handgun;

“(B) a semiautomatic assault weapon;

“(C) a large capacity ammunition feeding device; or

“(D) ammunition that is suitable for use only in a handgun or semiautomatic assault weapon.”;

(ii) in paragraph (2), by striking “a juvenile” and all that follows through “handgun.” and inserting the following: “less than 21 years of age to knowingly possess—

“(A) a handgun;

“(B) a semiautomatic assault weapon;

“(C) a large capacity ammunition feeding device; or

“(D) ammunition that is suitable for use only in a handgun or semiautomatic assault weapon.”;

(iii) by striking paragraphs (3), (4), and (5) and inserting the following:

“(3) This subsection does not apply to—

“(A) a temporary transfer of a covered firearm or covered ammunition to a person who is less than 21 years of age or to the possession or use of a covered firearm or covered ammunition by a person who is less than 21 years of age if the covered firearm or covered ammunition is possessed and used by the person—

“(i) in the course of employment, in the course of ranching or farming related to activities at the residence of the person (or on property used for ranching or farming at which the person, with the permission of the property owner or lessee, is performing activities related to the operation of the farm or ranch), target practice, hunting, or a course of instruction in the safe and lawful use of a covered firearm;

“(ii) with the prior written consent of the person's parent or guardian who is not prohibited by Federal, State, or local law from possessing a firearm, except—

“(I) during transportation by the person of an unloaded covered firearm in a locked container directly from the place of transfer to a place at which an activity described in clause (i) is to take place and transportation by the person of that covered firearm, unloaded and in a locked container, directly from the place at which such an activity took place to the transferor; or

“(II) with respect to ranching or farming activities as described in clause (i), a person who is less than 21 years of age may possess and use a covered firearm or covered ammunition with the prior written approval of the person's parent or legal guardian and at the direction of an adult who is not prohibited by Federal, State or local law from possessing a firearm;

“(iii) the person has the prior written consent in the person's possession at all times when a covered firearm or covered ammunition is in the possession of the person; and

“(iv) in accordance with State and local law;

“(B) a person who is less than 21 years of age who is a member of the Armed Forces of the United States or the National Guard who possesses or is armed with a covered firearm or covered ammunition in the line of duty;

“(C) a transfer by inheritance of title (but not possession) of a covered firearm or covered ammunition to a person who is less than 21 years of age; or

“(D) the possession of a covered firearm or covered ammunition by a person who is less than 21 years of age taken in defense of the person or other individuals against an intruder into the residence of the person or a residence in which the person is an invited guest.

“(4) A covered firearm or covered ammunition, the possession of which is transferred to a person who is less than 21 years of age in circumstances in which the transferor is not in violation of this subsection shall not be subject to permanent confiscation by the Government if its possession by the person who is less than 21 years of age subsequently becomes unlawful because of the conduct of the person who is less than 21 years of age, but shall be returned to the lawful owner when such covered firearm or covered ammunition is no longer required by the Government for the purposes of investigation or prosecution.

“(5) For purposes of this subsection—

“(A) the term ‘covered ammunition’ means ammunition that is suitable for use only in a handgun or a semiautomatic assault weapon; and

“(B) the term ‘covered firearm’ means—

“(i) a handgun;

“(ii) a semiautomatic assault weapon; or

“(iii) a large capacity ammunition feeding device.”; and

(iv) in paragraph (6)—

(I) in subparagraph (A), by striking “a juvenile defendant's parent or legal guardian” and inserting “the parent or legal guardian of a defendant who is less than 21 years of age”; and

(II) in subparagraph (C), by striking “a juvenile defendant” and inserting “a defendant who is less than 21 years of age”; and

(2) in section 924(a)(6)—

(A) in subparagraph (A)—

(i) in clause (i), by striking “juvenile” each place the term appears and inserting “person who is less than 21 years of age”; and

(ii) in clause (ii)—

(I) in the matter preceding subclause (I), by striking “juvenile” and inserting “person who is less than 21 years of age”;

(II) in subclause (I)—

(aa) by striking “juvenile” and inserting “person who is less than 21 years of age”; and

(bb) by striking “handgun or ammunition” and inserting “covered firearm or covered ammunition”; and

(III) in subclause (II), by striking “juvenile has” and inserting “person who is less than 21 years of age has”; and

(B) in subparagraph (B)—

(i) by striking “juvenile” each place the term appears and inserting “person who is less than 21 years of age”; and

(ii) by striking “handgun or ammunition” each place the term appears and inserting “covered firearm or covered ammunition”.