I 
115TH CONGRESS 
1ST SESSION H. R. 3999 
To amend title 18, United States Code, to prohibit the manufacture, posses-
sion, or transfer of any part or combination of parts that is designed 
and functions to increase the rate of fire of a semiautomatic rifle but 
does not convert the semiautomatic rifle into a machinegun, and for 
other purposes. 
IN THE HOUSE OF REPRESENTATIVES 
OCTOBER 10, 2017 
Mr. CURBELO of Florida (for himself, Mr. MOULTON, Mr. KING of New York, 
Mr. POLIS, Mr. LANCE, Ms. KELLY of Illinois, Mr. MEEHAN, Ms. ROSEN, 
Mr. ROYCE of California, Mr. O’ROURKE, Mr. SMITH of New Jersey, Mr. 
CARTWRIGHT, Mr. PAULSEN, Ms. GABBARD, Mr. COSTELLO of Pennsyl-
vania, Mr. KIHUEN, Ms. ROS-LEHTINEN, Mr. DELANEY, Mr. DENT, Mr. 
GENE GREEN of Texas, Ms. STEFANIK, and Mr. PERLMUTTER) intro-
duced the following bill; which was referred to the Committee on the Ju-
diciary 
A BILL 
To amend title 18, United States Code, to prohibit the manu-
facture, possession, or transfer of any part or combina-
tion of parts that is designed and functions to increase 
the rate of fire of a semiautomatic rifle but does not 
convert the semiautomatic rifle into a machinegun, and 
for other purposes. 
Be it enacted by the Senate and House of Representa-
tives of the United States of America in Congress assembled, 
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SECTION 1. PROHIBITION ON MANUFACTURE, POSSESSION, 
OR TRANSFER OF ANY PART OR COMBINA-
TION OF PARTS THAT IS DESIGNED AND 
FUNCTIONS TO INCREASE THE RATE OF FIRE 
OF A SEMIAUTOMATIC RIFLE BUT DOES NOT 
CONVERT THE SEMIAUTOMATIC RIFLE INTO 
A MACHINEGUN. 
(a) PROHIBITION.—Section 922 of title 18, United 
States Code, is amended by adding at the end the fol-
lowing: 
‘‘(aa) It shall be unlawful for any person— 
‘‘(1) in or affecting interstate or foreign com-
merce, to manufacture, possess, or transfer any part 
or combination of parts that is designed and func-
tions to increase the rate of fire of a semiautomatic 
rifle but does not convert the semiautomatic rifle 
into a machinegun; or 
‘‘(2) to manufacture, possess, or transfer any 
such part or combination of parts that have been 
shipped or transported in interstate or foreign com-
merce.’’. 
(b) PENALTIES.—Section 924(a)(1)(B) of such title 
is amended by striking ‘‘or (q)’’ and inserting ‘‘(q), or 
(aa)’’. 
(c) SENTENCING GUIDELINES.—Pursuant to its au-
thority under section 994 of title 28, United States Code, 
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and in accordance with this subsection, the United States 
Sentencing Commission shall amend and review the Fed-
eral sentencing guidelines and policy statements to ensure 
that the guidelines provide for a penalty enhancement of 
not less than 2 offense levels for a violation of section 
922(aa) of title 18 of such Code if the device described 
in such section 922(aa) has been— 
(1) used, carried, or possessed during or in re-
lation to a crime of violence or drug trafficking 
crime (as such terms are defined in section 
924(c)(3) of such title 18); or 
(2) smuggled unlawfully into or from the 
United States. 
(d) EFFECTIVE DATE.—This section and the amend-
ments made by this section shall apply with respect to con-
duct engaged in after the 90-day period that begins with 
the date of the enactment of this Act. 
Æ 
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