Undetectable Firearms Act of 1988
PL 100-649 (H.R.4445), enacted 11/10/1988

102 STAT. 3816 
PUBLIC LAW 100-649—NOV. 10, 1988 
Public Law 100-649 
100th Congress 
An Act 
Mov. 10, l^oo 
rp^ amend title 18, United States Code, to prohibit certain firearms especially useful 
[H.R. 4445] 
to terrorists. 
Be it enacted by the Senate and House of Representatives of the 
Undetectable 
United States of America in Congress assembled, 
Firearms Act of 
1988. 
SECTION 1. SHOFiT TITLE. 
industry 
This Act may be cited as the "Undetectable Firearms Act of 
Imports.' 
1988". 
Commerce and 
trade. 
SEC. 2. UNDETECTABLE FIREARMS. 
l^USC 921 note 
^^^ PROHIBITIONS.—Section 922 of title 18, United States Code, is 
amended by adding at the end the following: 
"(p)(l) It shall be unlawful for any person to manufacture, import, 
sell, ship, deliver, possess, transfer, or receive any firearm— 
"(A) that, after removal of grips, stocks, and magazines, is 
not as detectable as the Security Exemplar, by walk-through 
metal detectors calibrated and operated to detect the Security 
Exemplar; or 
"(B) any major component of which, when subjected to inspec-
tion by the types of x-ray machines commonly used at airports, 
does not generate an image that accurately depicts the shape of 
the component. Barium sulfate or other compounds may be used 
in the fabrication of the component. 
"(2) For purposes of this subsection— 
"(A) the term 'firearm' does not include the frame or receiver 
of any such weapon; 
"(B) the term 'major component' means, with respect to a 
firearm, 
the barrel, the slide or cylinder, or the frame or 
receiver of the firearm; and 
"(C) the term 'Security Exemplar' means an object, to be 
fabricated at the direction of the Secretary, that is— 
"(i) constructed of, during the 12-month period beginning 
on the date of the enactment of this subsection, 3.7 ounces 
of material type 17-4 PH stainless steel in a shape resem-
bling a handgun; and 
"(ii) suitable for testing and calibrating metal detectors: 
Regulations. 
Provided, however. That at the close of such 12-month period, 
and at appropriate times thereafter the Secretary shall promul-
gate regulations to permit the manufacture, importation, sale, 
shipment, delivery, possession, transfer, or receipt of firearms 
previously prohibited under this subparagraph that are as 
detectable as a 'Security Exemplar' which contains 3.7 ounces of 
material type 17-4 PH stainless steel, in a shape resembling a 
handgun, or such lesser amount as is detectable in view of 
advances in state-of-the-art developments in weapons detection 
technology. 
"(3) Under such rules and regulations as the Secretary shall 
prescribe, this subsection shall not apply to the manufacture, posses-
PUBLIC LAW 100-649—NOV. 10, 1988 
102 STAT. 3817 
sion, transfer, receipt, shipment, or delivery of a firearm by a 
licensed manufacturer or any person acting pursuant to a contract 
with a licensed manufacturer, for the purpose of examining and 
testing such firearm to determine whether paragraph (1) applies to 
such firearm. The Secretary shall ensure that rules and regulations 
adopted pursuant to this paragraph do not impair the manufacture 
of prototype firearms or the development of new technology. 
"(4) The Secretary shall permit the conditional importation of a 
firearm 
by a licensed importer or licensed manufacturer, for exam-
ination and testing to determine whether or not the unconditional 
importation of such firearm would violate this subsection. 
"(5) This subsection shall not apply to any firearm which— 
"(A) has been certified by the Secretary of Defense or the 
Director of Central Intelligence, after consultation with the 
Secretary and the Administrator of the Federal 
Aviation 
Administration, as necessary for military or intelligence ap-
plications; and 
"(B) is manufactured for and sold exclusively to military or 
intelligence agencies of the United States. 
"(6) This subsection shall not apply with respect to any firearm 
manufactured in, imported into, or possessed in the United States 
before the date of the enactment of the Undetectable Firearms Act 
of 1988.". 
(b) PENALTY.—Section 924 of title 18, United States Code, is 
amended— 
(1) in subsection (a)(1), by striking "or (c)" and inserting in 
lieu thereof ", (c), or (f)"; and 
(2) by adding at the end the following: 
"(f) In the case of a person who knowingly violates section 922(p), 
such person shall be fined under this title, or imprisoned not more 
than 5 years, or both.". 
(c) CONFORMING AMENDMENTS.—Section 925 of title 18, United 
States Code, is amended— 
(1) in subsection (a), by inserting after "chapter" the follow-
ing: ", except for provisions relating to firearms subject to the 
prohibitions of section 922(p),"; and 
(2) by adding at the end the following: 
"(f) The Secretary shall not authorize, under subsection (d), the 
importation of any firearm the importation of which is prohibited by 
section 922(p).". 
(d) RESEARCH AND DEVELOPMENT OF IMPROVED AIRPORT SECURITY 
49 u s e app. 
SYSTEMS.—The Administrator of the Federal Aviation Administra- 
^^^^ ^°^-
tion shall conduct such research and development as may be 
necessary to improve the effectiveness of airport security metal 
detectors and airport security x-ray systems in detecting 
firearms 
that, during the 10-year period beginning on the effective date of 
this Act, are subject to the prohibitions of section 922(p) of title 18, 
United States Code. 
(e) STUDIES T O IDENTIFY EQUIPMENT CAPABLE OF DISTINGUISHING 
18 USC 922 note. 
SECURITY EXEMPLAR FROM OTHER METAL OBJECTS LIKELY T O B E 
CARRIED O N O N E ' S PERSON.—The Attorney General, the Secretary of 
the Treasury, and the Secretary of Transportation shall each con-
duct studies to identify available state-of-the-art equipment capable 
of detecting the Security Exemplar (as defined in section 922(p)(2)(C) 
of title 18, United States Code) and distinguishing the Security 
Exemplar from innocuous metal objects likely to be carried on one's 
person. Such studies shall be completed within 6 months after the 
102 STAT. 3818 
PUBLIC LAW 100-649—NOV. 10, 1988 
date of the enactment of this Act and shall include a schedule 
providing for the installation of such equipment at the earliest 
practicable time at security checkpoints maintained or regulated by 
the agency conducting the study. Such equipment shall be installed 
in accordance with each schedule. In addition, such studies may 
include recommendations, where appropriate, concerning the use of 
secondary security equipment and procedures to enhance detection 
capability at security checkpoints. 
18 u s e 922 note. 
(f) EFFECTIVE D A T E AND SUNSET PROVISION.— 
(1) EFFECTIVE DATE.—This Act and the amendments made by 
this Act shall take effect on the 30th day beginning after the 
date of the enactment of this Act. 
(2) 10-YEAR SUNSET.—Effective 10 years after the effective date 
of this Act— 
(A) subsection (p) of section 922 of title 18, United States 
Code, is hereby repealed; 
(B) subsection (f) of section 924 of such title is hereby 
repealed; 
(C) subsection (f) of section 925 of such title is hereby 
repealed; 
(D) section 924(a)(1) of such title is amended by striking 
", (c), or (f)" and inserting in lieu thereof "or (c)"; and 
(E) section 925(a) of such title is amended by striking 
", except for provisions relating to firearms subject to the 
prohibitions of section 922(p),". 
Approved November 10, 1988. 
LEGISLATIVE HISTORY—H.R. 4445 (S. 2180): 
HOUSE REPORTS: No. 100-612 (Comm. on the Judiciary). 
CONGRESSIONAL RECORD, Vol. 134 (1988): 
May 10, considered and passed House. 
May 25, considered and passed Senate, eimended, in lieu of S. 2180. 
Oct. 20, House concurred in Senate amendment with an amendment. 
Oct. 21, Senate concurred in House amendment with an amendment. House 
concurred in Senate amendment.