Garland v. Cargill

P R E L I M I N A R Y P R I N T
Volume 602 U. S. Part 1
Pages 406–446
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OF
T H E S U P R E M E C O U R T
June 14, 2024
REBECCA A. WOMELDORF
reporter of decisions
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406 OCTOBER
TERM, 2023
Syllabus
GARLAND, ATTORNEY GENERAL, et al. v.
CARGIL
L
certiorari to the united states court of appeals for
the fth circuit
No. 22–976. Argued February 28, 2024—Decided June 14, 2024
The National Firearms Act of 1934 defnes a “machinegun” as “any weapon
which shoots, is designed to shoot, or can be readily restored to shoot,
automatically more than one shot, without manual reloading, by a single
function of the trigger.” 26 U. S. C. § 5845(b). With a machinegun, a
shooter can fre multiple times, or even continuously, by engaging the
trigger only once. This capability distinguishes a machinegun from a
semiautomatic frearm. With a semiautomatic frearm, the shooter can
fre only one time by engaging the trigger. Using a technique called
bump fring, shooters can fre semiautomatic frearms at rates approach-
ing those of some machineguns. A shooter who bump fres a rife uses
the frearm's recoil to help rapidly manipulate the trigger. Although
bump fring does not require any additional equipment, a “bump stock”
is an accessory designed to make the technique easier. A bump stock
does not alter the basic mechanics of bump fring, and the trigger still
must be released and reengaged to fre each additional shot.
For many years, the Bureau of Alcohol, Tobacco, Firearms and Explo-
sives (ATF) consistently took the position that semiautomatic rifes
equipped with bump stocks were not machineguns under § 5845(b).
ATF abruptly changed course when a gunman using semiautomatic ri-
fes equipped with bump stocks fred hundreds of rounds into a crowd
in Las Vegas, Nevada, killing 58 people and wounding over 500 more.
ATF subsequently proposed a rule that would repudiate its previous
guidance and amend its regulations to “clarify” that bump stocks are
machineguns. 83 Fed. Reg. 13442. ATF's Rule ordered owners of
bump stocks either to destroy or surrender them to ATF to avoid crimi-
nal prosecution.
Michael Cargill surrendered two bump stocks to ATF under protest,
then fled suit to challenge the Rule under the Administrative Procedure
Act. As relevant, Cargill alleged that ATF lacked statutory authority
to promulgate the Rule because bump stocks are not “machinegun[s]”
as defned in § 5845(b). After a bench trial, the District Court entered
judgment for ATF. The Fifth Circuit initially affrmed, but reversed
after rehearing en banc. A majority agreed that § 5845(b) is ambiguous
as to whether a semiautomatic rife equipped with a bump stock fts

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407
Syllabus
the statutory defnition of a machinegun and resolved that ambiguity in
Carg
ill's favor.
Held: ATF exceeded its statutory authority by issuing a Rule that classi-
fes a bump stock as a “machinegun” under § 5845(b). Pp. 415–429.
(a) A semiautomatic rife equipped with a bump stock is not a “ma-
chinegun” as defned by § 5845(b) because: (1) it cannot fre more than
one shot “by a single function of the trigger” and (2) even if it could, it
would not do so “automatically.” ATF therefore exceeded its statutory
authority by issuing a Rule that classifes bump stocks as machine-
guns. P. 415.
(b) A semiautomatic rife equipped with a bump stock does not fre
more than one shot “by a single function of the trigger.” The phrase
“function of the trigger” refers to the mode of action by which the trig-
ger activates the fring mechanism. No one disputes that a semiauto-
matic rife without a bump stock is not a machinegun because a shooter
must release and reset the trigger between every shot. And, any sub-
sequent shot fred after the trigger has been released and reset is the
result of a separate and distinct “function of the trigger.” Nothing
changes when a semiautomatic rife is equipped with a bump stock. Be-
tween every shot, the shooter must release pressure from the trigger
and allow it to reset before reengaging the trigger for another shot. A
bump stock merely reduces the amount of time that elapses between
separate “functions” of the trigger.
ATF argues that a shooter using a bump stock must pull the trigger
only one time to initiate a bump-fring sequence of multiple shots. This
initial trigger pull sets off a sequence—fre, recoil, bump, fre—that
allows the weapon to continue fring without additional physical manipu-
lation of the trigger by the shooter. This argument rests on the mis-
taken premise that there is a difference between the shooter fexing his
fnger to pull the trigger and pushing the frearm forward to bump the
trigger against his stationary fnger. Moreover, ATF's position is logi-
cally inconsistent because its reasoning would also mean that a semiau-
tomatic rife without a bump stock is capable of fring more than one
shot by a “single function of the trigger.” Yet, ATF agrees that is not
the case. ATF's argument is thus at odds with itself. Pp. 415–423.
(c) Even if a semiautomatic rife with a bump stock could fre more
than one shot “by a single function of the trigger,” it would not do so
“automatically.” Section 5845(b) specifes the precise action that must
“automatically” cause a weapon to fre “more than one shot”—a “single
function of the trigger.” If something more than a “single function of
the trigger” is required to fre multiple shots, the weapon does not sat-
isfy the statutory defnition. Firing multiple shots using a semiauto-

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408 GARLAND
v. CARGILL
Syllabus
matic rife with a bump stock requires more than a single function of
the
trigger. A shooter must maintain forward pressure on the rife's
front grip with his nontrigger hand. Without this ongoing manual
input, a semiautomatic rife with a bump stock will not fre multiple
shots.
ATF counters that machineguns also require continuous manual input
from a shooter: The shooter must both engage the trigger and keep it
pressed down to continue shooting. ATF argues there is no meaningful
difference between holding down the trigger of a traditional machinegun
and maintaining forward pressure on the front grip of a semiautomatic
rife with a bump stock. This argument ignores that Congress defned
a machinegun by what happens “automatically” “by a single function of
the trigger.” Simply pressing and holding the trigger down on a fully
automatic rife is not manual input in addition to a trigger's function.
By contrast, pushing forward on the front grip of a semiautomatic rife
equipped with a bump stock is not part of functioning the trigger.
Moreover, a semiautomatic rife with a bump stock is indistinguishable
from the Ithaca Model 37 shotgun, a weapon the ATF concedes cannot
fre multiple shots “automatically.” ATF responds that a shooter is less
physically involved with operating a bump-stock equipped rife than op-
erating the Model 37. It explains that once a shooter pulls the rife's
trigger a single time, the bump stock harnesses the frearm's recoil en-
ergy in a continuous back-and-forth cycle that allows the shooter to
attain continuous fring. But, even if one aspect of a weapon's operation
could be seen as “automatic,” that would not mean the weapon “shoots
. . . automatically more than one shot . . . by a single function of the
trigger.” § 5845(b) (emphasis added). Pp. 424–427.
(d) Abandoning the text, ATF attempts to shore up its position by
relying on the presumption against ineffectiveness. That presumption
weighs against interpretations of a statute that would “rende[r] the law
in a great measure nugatory, and enable offenders to elude its provisions
in the most easy manner.” The Emily, 9 Wheat. 381, 389. In ATF's
view, Congress “restricted machineguns because they eliminate the
manual movements that a shooter would otherwise need to make in
order to fre continuously” at a high rate of fre, as bump stocks do.
Brief for Petitioners 40. So, ATF reasons, concluding that bump stocks
are lawful “simply because the [trigger] moves back and forth . . . would
exalt artifce above reality and enable evasion of the federal machinegun
ban.” Id., at 41–42. The presumption against ineffectiveness cannot
do the work that ATF asks of it. Interpreting § 5845(b) to exclude
semiautomatic rifes equipped with bump stocks comes nowhere close to
making the statute useless. Pp. 427–428.
57 F. 4th 447, affrmed.

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409
Syllabus
Thomas, J., delivered the opinion of the Court, in which Roberts, C. J.,
and
Alito, Gorsuch, Kavanaugh, and Barrett, JJ., joined. Alito, J.,
fled a concurring opinion, post, p. 429. Sotomayor, J., fled a dissenting
opinion, in which Kagan and Jackson, JJ., joined, post, p. 429.
Principal Deputy Solicitor General Fletcher argued the
cause for petitioners. With him on the briefs were Solicitor
General Prelogar, Principal Deputy Assistant Attorney
General Boynton, Vivek Suri, Mark B. Stern, Michael S.
Raab, and Brad Hinshelwood.
Jonathan F. Mitchell argued the cause for respondent.
With him on the brief were Richard A. Samp, Markham S.
Chenoweth, and Sheng Li.*
*Briefs of amici curiae urging reversal were fled for the District of
Columbia et al. by Brian L. Schwalb, Attorney General of the District
of Columbia, Caroline S. Van Zile, Solicitor General, Ashwin P. Phatak,
Principal Deputy Solicitor General, and Russell C. Bogue, Assistant Attor-
ney General, by Patrick J. Griffn, Chief State's Attorney of Connecticut,
and by the Attorneys General for their respective States as follows: Kris-
tin K. Mayes of Arizona, Rob Bonta of California, Philip J. Weiser of
Colorado, William Tong of Connecticut, Kathleen Jennings of Delaware,
Anne E. Lopez of Hawaii, Kwame Raoul of Illinois, Aaron M. Frey of
Maine, Anthony G. Brown of Maryland, Andrea Joy Campbell of Massa-
chusetts, Dana Nessel of Michigan, Keith Ellison of Minnesota, Aaron D.
Ford of Nevada, Matthew J. Platkin of New Jersey, Raúl Torrez of New
Mexico, Letitia James of New York, Joshua H. Stein of North Carolina,
Ellen F. Rosenblum of Oregon, Michelle A. Henry of Pennsylvania, Peter
F. Neronha of Rhode Island, Charity R. Clark of Vermont, and Robert W.
Ferguson of Washington; for Chicago et al. by Myriam Zreczny Kasper,
Suzanne M. Loose, Anne L. Morgan, Kathleen A. Kenealy, Sylvia O.
Hinds-Radix, and Lyndsey M. Olson; for the American Medical Associa-
tion et al. by Michael J. Dell; for the Constitutional Accountability Center
by Elizabeth B. Wydra and Brianne J. Gorod; for the Giffords Law Center
to Prevent Gun Violence et al. by Ian Simmons; and for Patrick J. Charles
by L. Bradfeld Hughes.
Briefs of amici curiae urging affrmance were fled for the Buckeye
Institute by David C. Tryon; for the FPC Action Foundation by Joseph G.
S. Greenlee, Erik S. Jaffe, and Cody J. Wisniewski; for the Firearms Pol-
icy Coalition, Inc., by David H. Thompson, Peter A. Patterson, and John
D. Ohlendorf; for the Firearms Regulatory Accountability Coalition et al.
by Stephen J. Obermeier and Jeremy J. Broggi; for Gun Owners of

410 GARLAND
v. CARGILL
Opinion of the Court
Justice Thomas delivered the opinion of the Court.
Congress
has long restricted access to “ `machinegun[s],' ”
a category of frearms defned by the ability to “shoot, auto-
matically more than one shot . . . by a single function of the
trigger.” 26 U. S. C. § 5845(b); see also 18 U. S. C. § 922(o).
Semiautomatic frearms, which require shooters to reengage
the trigger for every shot, are not machineguns. This case
asks whether a bump stock—an accessory for a semiauto-
matic rife that allows the shooter to rapidly reengage the
trigger (and therefore achieve a high rate of fre)—converts
the rife into a “machinegun.” We hold that it does not and
therefore affrm.
I
A
Under the National Firearms Act of 1934, a “machinegun”
is “any weapon which shoots, is designed to shoot, or can be
readily restored to shoot, automatically more than one shot,
without manual reloading, by a single function of the trig-
ger.” § 5845(b). The statutory defnition also includes “any
part designed and intended . . . for use in converting a
weapon into a machinegun.” Ibid. With a machinegun, a
shooter can fre multiple times, or even continuously, by en-
gaging the trigger only once. This capability distinguishes
America et al. by William J. Olson, Jeremiah L. Morgan, Robert J. Olson,
and John I. Harris III; for the Manhattan Institute by Ilya Shapiro and
R. Trent McCotter; for the National Association for Gun Rights, Inc., et al.
by David A. Warrington, Gary M. Lawkowski, and Glenn D. Bellamy; for
the National Association of Criminal Defense Lawyers by Theodore M.
Cooperstein and David Oscar Markus; for the National Rife Association
of America, Inc., by Michael T. Jean and Erin M. Erhardt; for the Na-
tional Shooting Sports Foundation, Inc., by Paul D. Clement, Erin E.
Murphy, Matthew D. Rowen, and Lawrence G. Keane; for the Second
Amendment Law Center et al. by C. D. Michel and Konstadinos T. Moros;
and for Sen. Cynthia Lummis et al. by David B. Kopel and George A.
Mocsary.
Briefs of amici curiae were fled for FAMM by David Debold, Peter
Goldberger, and Mary Price; and for the Pacifc Legal Foundation by
Glenn E. Roper, Steven Simpson, and Caleb Kruckenberg.
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a machinegun from a semiautomatic frearm. With a semi-
automatic
frearm, the shooter can fre only one time by en-
gaging the trigger. The shooter must release and reengage
the trigger to fre another shot. Machineguns can ordinarily
achieve higher rates of fre than semiautomatic frearms be-
cause the shooter does not need to release and reengage the
trigger between shots.
Shooters have devised techniques for fring semiautomatic
frearms at rates approaching those of some machineguns.
One technique is called bump fring. A shooter who bump
fres a rife uses the frearm's recoil to help rapidly manipu-
late the trigger. The shooter allows the recoil from one shot
to push the whole frearm backward. As the rife slides
back and away from the shooter's stationary trigger fnger,
the trigger is released and reset for the next shot. Simulta-
neously, the shooter uses his nontrigger hand to maintain
forward pressure on the rife's front grip. The forward
pressure counteracts the recoil and causes the frearm (and
thus the trigger) to move forward and “bump” into the shoot-
er's trigger fnger. This bump reengages the trigger and
causes another shot to fre, and so on.
Bump fring is a balancing act. The shooter must main-
tain enough forward pressure to ensure that he will bump
the trigger with suffcient force to engage it. But, if the
shooter applies too much forward pressure, the rife will not
slide back far enough to allow the trigger to reset. The
right balance produces a reciprocating motion that permits
the shooter to repeatedly engage and release the trigger in
rapid succession.
Although bump fring does not require any additional
equipment, there are accessories designed to make the tech-
nique easier. A “bump stock” is one such accessory.
1
It re-
places a semiautomatic rife's stock (the back part of the rife
1
Some bump stocks (called mechanical bump stocks) rely on an internal
spring, rather than forward pressure from the shooter's nontrigger hand,
to force the rife and trigger forward after recoil. These devices are not
at issue in this case.

412 GARLAND
v. CARGILL
Opinion of the Court
that rests against the shooter's shoulder) with a plastic cas-
i
ng that allows every other part of the rife to slide back and
forth. This casing helps manage the back-and-forth motion
required for bump fring. A bump stock also has a ledge to
keep the shooter's trigger fnger stationary. A bump stock
does not alter the basic mechanics of bump fring. As with
any semiautomatic frearm, the trigger still must be released
and reengaged to fre each additional shot.
B
The question in this case is whether a bump stock trans-
forms a semiautomatic rife into a “machinegun,” as defned
by § 5845(b). For many years, the Bureau of Alcohol, To-
bacco, Firearms and Explosives (ATF) took the position that
semiautomatic rifes equipped with bump stocks were not
machineguns under the statute. On more than 10 separate
occasions over several administrations, ATF consistently
concluded that rifes equipped with bump stocks cannot “au-
tomatically” fre more than one shot “by a single function of
the trigger.” See App. 16–68. In April 2017, for example,
ATF explained that a rife equipped with a bump stock does
not “operat[e] automatically” because “forward pressure
must be applied with the support hand to the forward hand-
guard.” Id., at 66. And, because the shooter slides the rife
forward in the stock “to fre each shot, each succeeding shot
fr[es] with a single trigger function.” Id., at 67.
ATF abruptly reversed course in response to a mass shoot-
ing in Las Vegas, Nevada. In October 2017, a gunman fred
on a crowd attending an outdoor music festival in Las Vegas,
killing 58 people and wounding over 500 more. The gunman
equipped his weapons with bump stocks, which allowed him
to fre hundreds of rounds in a matter of minutes.
This tragedy created tremendous political pressure to out-
law bump stocks nationwide. Within days, Members of
Congress proposed bills to ban bump stocks and other de-
vices “designed . . . to accelerate the rate of fre of a semiau-
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tomatic rife.” S. 1916, 115th Cong., 1st Sess., § 2 (2017); see
a
lso H. R. 3947, 115th Cong., 1st Sess. (2017); H. R. 3999,
115th Cong., 1st Sess. (2017). None of these bills became
law. Similar proposals in the intervening years have also
stalled. See, e.g., H. R. 396, 118th Cong., 1st Sess. (2023);
S. 1909, 118th Cong., 1st Sess. (2023); H. R. 5427, 117th Cong.,
1st Sess. (2021).
While the frst wave of bills was pending, ATF began con-
sidering whether to reinterpret § 5845(b)'s defnition of “ma-
chinegun” to include bump stocks. It proposed a rule that
would amend its regulations to “clarify” that bump stocks
are machineguns. 83 Fed. Reg. 13442 (2018). ATF's about-
face drew criticism from some observers, including those
who agreed that bump stocks should be banned. Senator
Dianne Feinstein, for example, warned that ATF lacked stat-
utory authority to prohibit bump stocks, explaining that the
proposed regulation “ `hinge[d] on a dubious analysis' ” and
that the “ `gun lobby and manufacturers [would] have a feld
day with [ATF's] reasoning ' ” in court. Statement on Regu-
lation To Ban Bump Stocks (Mar. 23, 2018). She asserted
that “ `legislation is the only way to ban bump stocks.' ”
Ibid.
ATF issued its fnal Rule in 2018. 83 Fed. Reg. 66514.
The agency's earlier regulations simply restated § 5845(b)'s
statutory defnition. Ibid. The fnal Rule amended those
regulations by adding the following language:
“[T]he term `automatically' as it modifes `shoots, is de-
signed to shoot, or can be readily restored to shoot,'
means functioning as the result of a self-acting or self-
regulating mechanism that allows the fring of multiple
rounds through a single function of the trigger; and `sin-
gle function of the trigger' means a single pull of the
trigger and analogous motions. The term `machinegun'
includes a bump-stock-type device, i.e., a device that
allows a semi-automatic frearm to shoot more than one
shot with a single pull of the trigger by harnessing the
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414 GARLAND
v. CARGILL
Opinion of the Court
recoil energy of the semi-automatic frearm to which it
is
affxed so that the trigger resets and continues fring
without additional physical manipulation of the trigger
by the shooter.” Id., at 66553–66554.
The fnal Rule also repudiated ATF's previous guidance that
bump stocks did not qua l i fy as “mach i neg uns” under
§ 5845(b). Id., at 66530–66531. And, it ordered owners of
bump stocks to destroy them or surrender them to ATF
within 90 days. Id., at 66530. Bump-stock owners who
failed to comply would be subject to criminal prosecution.
Id., at 66525; see also 18 U. S. C. § 922(o)(1).
C
Michael Cargill surrendered two bump stocks to ATF
under protest. He then fled suit to challenge the fnal Rule,
asserting a claim under the Administrative Procedure Act.
As relevant, Cargill alleged that ATF lacked statutory au-
thority to promulgate the fnal Rule because bump stocks
are not “machinegun[s]” as defned in § 5845(b). After a
bench trial, the District Court entered judgment for ATF.
The court concluded that “a bump stock fts the statutory
defi niti on of a `mach i neg un. ' ” Carg i ll v. Bar r, 502
F. Supp. 3d 1163, 1194 (WD Tex. 2020).
The Court of Appeals initially affrmed, 20 F. 4th 1004
(CA5 2021), but later reversed after rehearing en banc, 57
F. 4th 447 (CA5 2023). A majority agreed, at a minimum,
that § 5845(b) is ambiguous as to whether a semiautomatic
rife equipped with a bump stock fts the statutory defnition
of a machinegun. And, the majority concluded that the rule
of lenity required resolving that ambiguity in Cargill's favor.
Id., at 469; see also id., at 450, n. An eight-judge plurality
determined that the statutory defnition of “machinegun” un-
ambiguously excludes such weapons. A semiautomatic rife
equipped with a bump stock, the plurality reasoned, fres
only one shot “each time the trigger `acts,' ” id., at 459, and
so does not fre “more than one shot . . . by a single function
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415
Opinion of the Court
of the trigger,” § 5845(b). The plurality also concluded that
a
bump stock does not enable a semiautomatic rife to fre
more than one shot “automatically” because the shooter must
“maintain manual, forward pressure on the barrel.” Id.,
at 463.
We granted certiorari, 601 U. S. ––– (2023), to address a
split among the Courts of Appeals regarding whether bump
stocks meet § 5845(b)'s defnition of “machinegun.”
2
We
now affrm.
II
Section 5845(b) defnes a “machinegun” as any weapon ca-
pable of fring “automatically more than one shot . . . by a
single function of the trigger.” We hold that a semiauto-
matic rife equipped with a bump stock is not a “machinegun”
because it cannot fre more than one shot “by a single func-
tion of the trigger.” And, even if it could, it would not do
so “automatically.” ATF therefore exceeded its statutory
authority by issuing a Rule that classifes bump stocks as
machineguns.
A
A semiautomatic rife equipped with a bump stock does
not fre more than one shot “by a single function of the trig-
ger.” With or without a bump stock, a shooter must release
and reset the trigger between every shot. And, any subse-
quent shot fred after the trigger has been released and reset
is the result of a separate and distinct “function of the trig-
ger.” All that a bump stock does is accelerate the rate of
fre by causing these distinct “function[s]” of the trigger to
occur in rapid succession.
As always, we start with the statutory text, which refers
to “a single function of the trigger.” The “function” of an
2
See, e.g., Hardin v. Bureau of Alcohol, Tobacco, Firearms and Explo-
sives, 65 F. 4th 895 (CA6 2023); Guedes v. Bureau of Alcohol, Tobacco,
Firearms and Explosives, 45 F. 4th 306 (CADC 2022); Aposhian v. Barr,
958 F. 3d 969 (CA10 2020).
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v. CARGILL
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object is “the mode of action by which it fulfls its purpose.”
4
Oxford English Dictionary 602 (1933); see also American
Heritage Dictionary 533 (1969) (“The natural or proper ac-
tion for which a . . . mechanism . . . is ftted or employed”).
And, a “trigger” is an apparatus, such as a “movable catch
or lever,” that “sets some force or mechanism in action.” 11
Oxford English Dictionary, at 357; see also American Heri-
tage Dictionary, at 1371 (“The lever pressed by the fnger to
discharge a frearm” or “[a]ny similar device used to release
or activate a mechanism”); Webster's New International Dic-
tionary 2711 (2d ed. 1934) (“A piece, as a lever, connected
with a catch or detent as a means of releasing it; specif.,
Firearms, the part of a lock moved by the fnger to release
the cock in fring ”). The phrase “function of the trigger”
thus refers to the mode of action by which the trigger acti-
vates the fring mechanism. For most frearms, including
the ones at issue here, the trigger is a curved metal lever.
On weapons with these standard trigger mechanisms, the
phrase “function of the trigger” means the physical trigger
movement required to shoot the frearm.
No one disputes that a semiautomatic rife without a bump
stock is not a machinegun because it fres only one shot per
“function of the trigger.” That is, engaging the trigger a
single time will cause the fring mechanism to discharge only
one shot. To understand why, it is helpful to consider the
mechanics of the fring cycle for a semiautomatic rife. Be-
cause the statutory defnition is keyed to a “function of the
trigger,” only the trigger assembly is relevant for our pur-
poses. Although trigger assemblies for semiautomatic rifes
vary, the basic mechanics are generally the same. The fol-
lowing series of illustrations depicts how the trigger assem-
bly on an AR–15 style semiautomatic rife works.
3
In each
illustration, the front of the rife (i.e., the barrel) would be
pointing to the left.
3
These illustrations are found in the Brief for FPC Action Foundation
as Amicus Curiae 14–15.
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417
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We begin with an overview of the relevant components:
Figure 1.
The trigger is a simple lever that moves backward and for-
ward. P. Sweeney, Gunsmithing the AR–15, p. 131 (2016).
The square point at the top left edge of the trigger locks into
a notch at the bottom of the hammer. P. Sweeney, Gun-
smithing: Rifes 269 (1999). The hammer is a spring-loaded
part that swings forward toward the barrel and strikes the
fring pin, causing a shot to fre. Ibid. The disconnector is
the component responsible for resetting the hammer to its
original position after a shot is fred. Ibid.
We turn next to how these components operate:
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v. CARGILL
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Figure 2.
When the shooter engages the trigger by moving it back-
ward (as indicated by the arrow), the square point of the
trigger pivots downward and out of the notch securing the
hammer. Ibid. This movement releases the spring-loaded
hammer, allowing it to swing forward. Ibid.
Figure 3.
At the top of the hammer's rotation, it strikes the fring pin,
causing the weapon to fre a single shot. See ibid.

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Figure 4.
The frearm then ejects the spent cartridge from the cham-
ber and loads a new one in its place. D. Long, The Complete
AR–15/M16 Sourcebook 206 (2001). The mechanism that
performs this task swings the hammer backward at the same
time. Ibid.
Figure 5.
As the hammer swings backward, it latches onto the discon-
nector. Sweeney, Gunsmithing: Rifes, at 269. This latch-

420 GARLAND
v. CARGILL
Opinion of the Court
ing (circled above) prevents the hammer from swinging
for
ward again after a new cartridge is loaded into the cham-
ber. Ibid. The disconnector will hold the hammer in that
position for as long as the shooter holds the trigger back,
thus preventi ng the firear m from fir ing another shot.
4
Ibid.
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Figure 6.
Finally, when the shooter takes pressure off the trigger and
allows it to move forward (as indicated by the arrow), the
hammer slips off the disconnector just as the square point of
the trigger rises into the notch on the hammer (circled
above). Ibid. The trigger mechanism is thereby reset to
4
Machinegun variants of the AR–15 style rife include an additional com-
ponent known as an auto sear. The auto sear catches the hammer as it
swings backwards, but will release it again once a new cartridge is loaded
if the trigger is being held back. P. Sweeney, 1 The Gun Digest Book of
the AR–15, p. 38 (2005). An auto sear thus permits a shooter to fre multi-
ple shots while engaging the trigger only once. ATF has accordingly rec-
ognized that modifying a semiautomatic rife or handgun with an auto sear
converts it into a machinegun. See ATF Ruling 81–4.

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the original position shown in Figure 1. A semiautomatic
r
ife must complete this cycle for each shot fred.
5
ATF does not dispute that this complete process is what
constitutes a “single function of the trigger.” A shooter
may fre the weapon again after the trigger has reset, but
only by engaging the trigger a second time and thereby ini-
tiating a new fring cycle. For each shot, the shooter must
engage the trigger and then release the trigger to allow it
to reset. Any additional shot fred after one cycle is the
result of a separate and distinct “function of the trigger.”
Nothing changes when a semiautomatic rife is equipped
with a bump stock. The fring cycle remains the same. Be-
tween every shot, the shooter must release pressure from
the trigger and allow it to reset before reengaging the trig-
ger for another shot. A bump stock merely reduces the
amount of time that elapses between separate “functions” of
the trigger. The bump stock makes it easier for the shooter
to move the frearm back toward his shoulder and thereby
release pressure from the trigger and reset it. And, it helps
the shooter press the trigger against his fnger very quickly
thereafter. A bump stock does not convert a semiautomatic
rife into a machinegun any more than a shooter with a
lightning-fast trigger fnger does. Even with a bump stock,
a semiautomatic rife will fre only one shot for every “func-
tion of the trigger.” So, a bump stock cannot qualify as a
machinegun under § 5845(b)'s defnition.
Although ATF agrees on a semiautomatic rife's mechanics,
it nevertheless insists that a bump stock allows a semiauto-
matic rife to fre multiple shots “by a single function of the
trigger.” ATF starts by interpreting the phrase “single
function of the trigger” to mean “a single pull of the trigger
and analogous motions.” 83 Fed. Reg. 66553. A shooter
using a bump stock, it asserts, must pull the trigger only one
5
An animated graphic that displays the relevant movements is available
at https://www.supremecourt.gov/media / images/AR-15.gif.

422 GARLAND
v. CARGILL
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time to initiate a bump-fring sequence of multiple shots.
Id
., at 66554. This initial trigger pull sets off a sequence—
fre, recoil, bump, fre—that allows the weapon to continue
fring “without additional physical manipulation of the trig-
ger by the shooter. ” Ib i d. Accordi ng to ATF, a l l the
shooter must do is keep his trigger fnger stationary on the
bump stock's ledge and maintain constant forward pressure
on the front grip to continue fring. The dissent offers similar
reasoning. See post, at 435–437 (opinion of Sotomayor, J.).
This argument rests on the mistaken premise that there
is a difference between a shooter fexing his fnger to pull
the trigger and a shooter pushing the frearm forward to
bump the trigger against his stationary fnger. ATF and
the dissent seek to call the shooter's initial trigger pull a
“function of the trigger” while ignoring the subsequent
“bumps” of the shooter's fnger against the trigger before
every additional shot. But, § 5845(b) does not defne a ma-
chinegun based on what type of human input engages the
trigger—whether it be a pull, bump, or something else. Nor
does it defne a machinegun based on whether the shooter
has assistance engaging the trigger. The statutory defni-
tion instead hinges on how many shots discharge when the
shooter engages the trigger. And, as we have explained, a
semiautomatic rife will fre only one shot each time the
shooter engages the trigger—with or without a bump stock.
6
Supra, at 415–421.
In any event, ATF's argument cannot succeed on its own
terms. The fnal Rule defnes “function of the trigger” to
6
The dissent says that we “resis[t]” the “ordinary understanding of the
term `function of the trigger' with two technical arguments.” Post, at
439. But, the arguments it refers to explain why, even assuming a semi-
automatic rife equipped with a bump stock could fre more than one shot
by a single function of the trigger, it could not do so “automatically.” See
in fra, at 424–427. Those arguments have nothing to do with our explana-
tion of what a “single function of the trigger” means. Ibid.
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include not only “a single pull of the trigger” but also any
“ana
logous motions.” 83 Fed. Reg. 66553. ATF concedes
that one such analogous motion that qualifes as a single
function of the trigger is “sliding the rife forward” to bump
the trigger. Brief for Petitioners 22. But, if that is true,
then every bump is a separate “function of the trigger,” and
semiautomatic rifes equipped with bump stocks are there-
fore not machineguns. ATF resists the natural implication
of its reasoning, insisting that the bumping motion is a “func-
tion of the trigger” only when it initiates, but not when it
continues, a fring sequence. But, Congress did not write
a statutory defnition of “machinegun” keyed to when a fr-
ing sequence begins and ends. Section 5845(b) asks only
whether a weapon fres more than one shot “by a single func-
tion of the trigger.”
Finally, the position that ATF and the dissent endorse is
logically inconsistent. They reason that a semiautomatic
rife equipped with a bump stock fres more than one shot by
a single function of the trigger because a shooter “need only
pull the trigger and maintain forward pressure” to “activate
continuous fre.” Post, at 438–439; see also Brief for Peti-
tioners 23. If that is correct, however, then the same should
be true for a semiautomatic rife without a bump stock.
After all, as the dissent and ATF themselves acknowledge,
a shooter manually bump fring a semiautomatic rife can
achieve continuous fre by holding his trigger fnger station-
ary and maintaining forward pressure with his nontrigger
hand. See post, at 433–434; 83 Fed. Reg. 66533. Yet, they
agree that a semiautomatic rife without a bump stock “fres
only one shot each time the shooter pulls the trigger.” Post,
at 433; see also 83 Fed. Reg. 66534. Their argument is thus
at odds with itself.
We conclude that a semiautomatic rife equipped with a
bump stock is not a “machinegun” because it does not fre
more than one shot “by a single function of the trigger.”

424 GARLAND
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B
A
bump stock is not a “machinegun” for another reason:
Even if a semiautomatic rife with a bump stock could fre
more than one shot “by a single function of the trigger,” it
would not do so “automatically.” Section 5845(b) asks
whether a weapon “shoots . . . automatically more than one
shot . . . by a single function of the trigger.” The statute
thus specifes the precise action that must “automatically”
cause a weapon to fre “more than one shot”—a “single func-
tion of the trigger.” If something more than a “single func-
tion of the trigger” is required to fre multiple shots, the
weapon does not satisfy the statutory defnition. As Judge
Henderson put it, the “statutory defnition of `machinegun'
does not include a frearm that shoots more than one round
`automatically' by a single pull of the trigger AND THEN
SOME.” Guedes v. Bureau of Alcohol, Tobacco, Firearms
and Explosives, 920 F. 3d 1, 44 (CADC 2019) (opinion concur-
ring in part and dissenting in part).
Firing multiple shots using a semiautomatic rife with a
bump stock requires more than a single function of the trig-
ger. A shooter must also actively maintain just the right
amount of forward pressure on the rife's front grip with his
nontrigger hand. See supra, at 411–412. Too much for-
ward pressure and the rife will not slide back far enough to
release and reset the trigger, preventing the rife from fring
another shot. Too little pressure and the trigger will not
bump the shooter's trigger fnger with suffcient force to fre
another shot. Without this ongoing manual input, a semiau-
tomatic rife with a bump stock will not fre multiple shots.
Thus, fring multiple shots requires engaging the trigger one
time—and then some.
7
7
The dissent seemingly concedes this point, repeatedly recognizing that
the shooter must both pull the trigger and maintain forward pressure on
the front grip. See, e.g., post, at 435 (“[A] single pull of the trigger
provides continuous fre as long as the shooter maintains forward pressure
on the gun”); ibid. (“A bump-stock-equipped semiautomatic rife is a
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ATF and the dissent counter that machineguns also re-
quire
continuous manual input from a shooter: He must both
engage the trigger and keep it pressed down to continue
shooting. In their view, there is no meaningful difference
between holding down the trigger of a traditional machine-
gun and maintaining forward pressure on the front grip of a
semiautomatic rife with a bump stock. This argument ig-
nores that Congress defned a machinegun by what happens
“automatically” “by a single function of the trigger.” Sim-
ply pressi ng and holdi ng the tr igger down on a fu l ly
automatic rife is not manual input in addition to a trigger's
function—it is what causes the trigger to function in the frst
place. By contrast, pushing forward on the front grip of a
semiautomatic rife equipped with a bump stock is not part
of functioning the trigger. After all, pushing on the front
grip will not cause the weapon to fre unless the shooter also
engages the trigger with his other hand. Thus, while a fully
automatic rife fres multiple rounds “automatically . . . by
a single function of the trigger,” a semiautomatic rife
equipped with a bump stock can achieve the same result only
by a single function of the trigger and then some.
Moreover, a semiautomatic rife with a bump stock is indis-
tinguishable from another weapon that ATF concedes cannot
fre multiple shots “automatically”: the Ithaca Model 37 shot-
gun. The Model 37 allows the user to “slam fre”—that is,
fre multiple shots by holding down the trigger while operat-
ing the shotgun's pump action. Each pump ejects the spent
cartridge and loads a new one into the chamber. If the
shooter is holding down the trigger, the new cartridge will
machinegun because . . . a shooter can . . . fre continuous shots without
any human input beyond maintaining forward pressure”); post, at 438 (“[A]
shooter of a bump-stock-equipped AR–15 need only pull the trigger and
maintain forward pressure”); post, at 441 (“After a shooter pulls the trig-
ger, if he maintains continuous forward pressure on the gun, the bump
stock harnesses the recoil to move the curved lever back and forth against
his fnger”).
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fre as soon as it is loaded. According to ATF, the Model 37
fres
more than one shot by a single function of the trigger,
but it does not do so “automatically” because the shooter
must manually operate the pump action with his nontrigger
hand. See 83 Fed. Reg. 66534. That logic mandates the
same result here. Maintaining the proper amount of for-
ward pressure on the front grip of a bump-stock equipped
rife is no less additional input than is operating the pump
action on the Model 37.
8
ATF responds that a shooter is less physically involved
with operating a bump-stock equipped rife than operating
the Model 37's pump action. Once the shooter pulls the ri-
fe's trigger a single time, the bump stock “harnesses the
frearm's recoil energy in a continuous back-and-forth cycle
that allows the shooter to attain continuous fring.” Id., at
66519. But, even if one aspect of a weapon's operation could
be seen as “automatic,” that would not mean the weapon
“shoots . . . automatically more than one shot . . . by a single
function of the trigger.” § 5845(b) (emphasis added). After
all, many weapons have some “automatic” features. For ex-
ample, semiautomatic rifes eject the spent cartridge from
the frearm's chamber and load a new one in its place without
any input from the shooter. See supra, at 419. A semiau-
tomatic rife is therefore “automatic” in the general sense
that it performs some operations that would otherwise need
to be completed by hand. But, as all agree, a semiautomatic
rife cannot fre more than one shot “automatically . . . by a
single function of the trigger” because the shooter must do
8
The dissent attempts to undermine this analogy by pointing out that
a Model 37 requires manual reloading and therefore cannot qualify as a
machinegun under § 5845(b). Post, at 441, n. 5. But, that is beside the
point. As ATF itself agrees, the Model 37 is not a machinegun for an-
other, independent reason: It cannot “automatically” fre more than one
shot by a single function of the trigger. See Brief for Petitioners 38.
And, as explained, the reasons why a Model 37 cannot do so apply with
equal force to semiautomatic rifes equipped with bump stocks.
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more than simply engage the trigger one time. The same is
tr
ue of a semiautomatic rife equipped with a bump stock.
Thus, even if a semiautomatic rife could fre more than
one shot by a single function of the trigger, it would not do
so “automatically.”
C
Abandoning the text, ATF and the dissent attempt to
shore up their position by relying on the presumption against
ineffectiveness. That presumption weighs against interpre-
tations of a statute that would “rende[r] the law in a great
measure nugatory, and enable offenders to elude its provi-
sions in the most easy manner.” The Emily, 9 Wheat. 381,
389 (1824). It is a modest corollary to the commonsense
proposition “that Congress presumably does not enact use-
less laws.” United States v. Castleman, 572 U. S. 157, 178
(2014) (Scalia, J., concurring in part and concurring in
judgment).
In ATF's view, Congress “restricted machineguns because
they eliminate the manual movements that a shooter would
otherwise need to make in order to fre continuously” at a
high rate of fre, as bump stocks do. Brief for Petitioners
40. So, ATF reasons, concluding that bump stocks are law-
ful “simply because the [trigger] moves back and forth . . .
would exalt artifce above reality and enable evasion of the
federal machinegun ban.” Id., at 41–42 (internal quotation
marks omitted). The dissent endorses a similar view. See
post, at 442–446.
The presumption against ineffectiveness cannot do the
work that ATF and the dissent ask of it. A law is not use-
less merely because it draws a line more narrowly than one
of its conceivable statutory purposes might suggest. Inter-
preting § 5845(b) to exclude semiautomatic rifes equipped
with bump stocks comes nowhere close to making it useless.
Under our reading, § 5845(b) still regulates all traditional
machineguns. The fact that it does not capture other weap-
ons capable of a high rate of fre plainly does not render the
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428 GARLAND
v. CARGILL
Opinion of the Court
law useless. Moreover, it is diffcult to understand how ATF
can
plausibly argue otherwise, given that its consistent posi-
tion for almost a decade in numerous separate decisions was
that § 5845(b) does not capture semiautomatic rifes equipped
with bump stocks. See App. 16–68. Curiously, the dissent
relegates ATF's about-face to a footnote, instead pointing to
its classifcation of other devices. See post, at 441–446, and
n. 6.
The dissent's additional argument for applying the pre-
sumption against ineffectiveness fails on its own terms. To
arg ue that our interpretati on makes § 5845( b) “far less
effective,” the dissent highlights that a shooter with a
bump-stock-equipped rife can achieve a rate of fre that ri-
vals traditional machineguns. Post, at 445. But, the dis-
sent elsewhere acknowledges that a shooter can do the same
with an unmodifed semiautomatic rife using the manual
bump-fring technique. See post, at 433–434. The dissent
thus fails to prove that our reading makes § 5845(b) “far less
effective,” much less ineffective (as is required to invoke the
presumption). In any event, Congress could have linked the
defnition of “machinegun” to a weapon's rate of fre, as the
dissent would prefer. But, it instead enacted a statute that
turns on whether a weapon can fre more than one shot “au-
tomatically . . . by a single function of the trigger.”
§ 5845(b). And, “it is never our job to rewrite . . . statutory
text under the banner of speculation about what Congress
might have done.” Henson v. Santander Consumer USA
Inc., 582 U. S. 79, 89 (2017).
9
9
The dissent concludes by claiming that our interpretation of § 5845(b)
“renders Congress's clear intent readily evadable.” Post, at 445. And,
it highlights that “[e]very Member of the majority has previously em-
phasized that the best way to respect congressional intent is to adhere
to the ordinary understanding of the terms Congress uses.” Ibid. But,
“[w]hen Congress takes the trouble to defne the terms it uses, a court
must respect its defnitions as virtually conclusive. . . . This Court will not
deviate from an express statutory defnition merely because it varies from
the term's ordinary meaning.” Department of Agriculture Rural Devel-

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as: 602 U. S. 406 (2024)
429
Sotomayor, J., dissenting
III
F
or the foregoing reasons, we affrm the judgment of the
Court of Appeals.
It is so ordered.
Justice Alito, concurring.
I join the opinion of the Court because there is simply no
other way to read the statutory language. There can be lit-
tle doubt that the Congress that enacted 26 U. S. C. § 5845(b)
would not have seen any material difference between a ma-
chinegun and a semiautomatic rife equipped with a bump
stock. But the statutory text is clear, and we must follow it.
The horrible shooting spree in Las Vegas in 2017 did not
change the statutory text or its meaning. That event dem-
onstrated that a semiautomatic rife with a bump stock can
have the same lethal effect as a machinegun, and it thus
strengthened the case for amending § 5845(b). But an event
that highlights the need to amend a law does not itself
change the law's meaning.
There is a simple remedy for the disparate treatment of
bump stocks and machineguns. Congress can amend the
law—and perhaps would have done so already if ATF had
stuck with its earlier interpretation. Now that the situation
is clear, Congress can act.
Justice Sotomayor, with whom Justice Kagan and
Justice Jackson join, dissenting.
On October 1, 2017, a shooter opened fre from a hotel room
overlooking an outdoor concert in Las Vegas, Nevada, in
what would become the deadliest mass shooting in U. S. his-
tory. Within a matter of minutes, using several hundred
rounds of ammunition, the shooter killed 58 people and
wounded over 500. He did so by affxing bump stocks to
opment Rural Housing Service v. Kirtz, 601 U. S. 42, 59 (2024) (internal
quotation marks and alteration omitted) (unanimous opinion).
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commonly available, semiautomatic rifes. These simple de-
v
ices harness a rife's recoil energy to slide the rife back and
forth and repeatedly “bump” the shooter's stationary trigger
fnger, creating rapid fre. All the shooter had to do was
pull the trigger and press the gun forward. The bump stock
did the rest.
Congress has sharply restricted civilian ownership of ma-
chineguns since 1934. Federal law defnes a “machinegun”
as a weapon that can shoot “automatically more than one
shot, without manual reloading, by a single function of the
trigger.” 26 U. S. C. § 5845(b). Shortly after the Las Vegas
massacre, the Trump administration, with widespread bipar-
tisan support, banned bump stocks as machineguns under
the statute.
Today, the Court puts bump stocks back in civilian hands.
To do so, it casts aside Congress's defnition of “machinegun”
and seizes upon one that is inconsistent with the ordinary
meaning of the statutory text and unsupported by context
or purpose. When I see a bird that walks like a duck, swims
like a duck, and quacks like a duck, I call that bird a duck.
A bump-stock-equipped semiautomatic rife fres “automati-
cally more than one shot, without manual reloading, by a
single function of the trigger.” § 5845(b). Because I, like
Congress, call that a machinegun, I respectfully dissent.
I
A
Machineguns were originally developed in the 19th cen-
tury as weapons of war. See J. Ellis, The Social History of
the Machine Gun 21–45 (1986) (Ellis). Smaller and lighter
submachine guns were not commercially available until the
1920s. See Brief for Patrick J. Charles as Amicus Curiae
5 (Charles Brief ). Although these weapons were originally
marketed to law enforcement, they inevitably made it into the
hands of gangsters. See id., at 8–9; Ellis 149–165. Gang-
sters like Al Capone used machineguns to rob banks, ambush
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Sotomayor, J., dissenting
the police, and murder rivals. See Ellis 153–154, 157–158.
N
ewspaper headlines across the country fashed “ `Gangsters
Use Machine Guns,' ” “ `Machine Gun Used in Bank Hold-
Up,' ” and “ `Machine Gun Thugs Kill Postal Employee.' ”
Charles Brief 9.
Congress responded in 1934 by sharply restricting civilian
ownership of machineguns. See National Firearms Act of
1934, §§ 3–6, 48 Stat. 1236, 1237–1238. The Senate Report
explaining the 1934 Act emphasized that the “gangster as a
law violator must be deprived of his most dangerous weapon,
the machine gun.” S. Rep. No. 1444, 73d Cong., 2d Sess.,
1–2. “[W]hile there is justifcation for permitting the citizen
to keep a pistol or revolver for his own protection . . . , there
is no reason why anyone except a law offcer should have a
machine gun.” Id., at 2.
These early machineguns allowed a shooter to fre in a
variety of ways. Some would fre continuously with a single
pull of the trigger or push of a button. See Charles Brief 7,
and n. 12 (noting that a Browning M1918 rife fred eight
rounds “ `in a second with one pull of the trigger' ”); see also
Brief for Petitioners 22 (noting that a Browning M2 fred
with a push of the thumb). Others, such as the famous
Thompson Submachine Gun Caliber .45, or “Tommy Gun,”
would fre continuously only so long as the shooter main-
tained backward pressure on the trigger; a shooter could still
fre single shots by pulling and releasing the trigger each
time. See Test of Thompson Submachine Gun, 69 Army and
Navy Register 355 (Apr. 9, 1921) (noting that the shooter of
a Tommy Gun “can fre the contents of the magazine with a
single prolonged pull or fre a single shot by merely releasing
the trigger”). The internal mechanisms of automatic-fre
weapons also varied enormously, with many (such as the
Tommy Gun) relying principally on the recoil energy
produced by each bullet's discharge to effectuate automatic
fre. See, e.g., War Dept., Basic Field Manual: Thompson
Submachine Gun, Caliber .45, M1928A1, p. 1 (1941) (“The
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Thompson submachine gun . . . is an air-cooled, recoil-
operated,
magazine-fed weapon”); W. Smith, Small Arms of
the World: The Basic Manual of Military Small Arms 165
(1955) (describing Tommy guns as “recoil operated weapons
on the elementary blowback principle”).
To account for these differences, Congress adopted a def-
nition of “machinegun” that captured “any weapon which
shoots, or is designed to shoot, automatically . . . more than
one shot, without manual reloading, by a single function of
the trigger.” National Firearms Act, 48 Stat. 1236. That
essential defnition still governs today. See 26 U. S. C.
§ 5845(b).
1
B
The archetypal modern “machinegun” is the military's
standard-issue M16 assault rife. With an M16 in automatic
mode, the shooter pulls the trigger once to achieve a fre
rate of 700 to 950 rounds per minute. See Dept. of Defense,
Defense Logistics Agency, Small Arms, https://www.dla.mil/
Disposition-Services/Offers/Law-Enforcement/ Weapons.
An internal mechanism automates the M16's continuous fre,
so that all the shooter has to do is keep backward pressure
on the trigger. See Brief for Giffords Law Center to Pre-
vent Gun Violence et al. as Amici Curiae 9–11 (Giffords
Brief ) (discussing internal fring mechanism of M16). If
the shooter stops putting pressure on the trigger, the gun
stops fring.
Semiautomatic weapons are not “machineguns” under the
statute. Take, for instance, an AR–15-style semiautomatic
rife. To rapidly fre an AR–15, a shooter must rapidly pull
the trigger himself. It is “semi” automatic because, al-
1
Congress has twice strengthened the regulation of machineguns over
the years without substantially updating the defnition. See Gun Control
Act of 1968, 82 Stat. 1213 (expanding registration requirements and
strengthening criminal penalties); Firearms Owners' Protection Act, 100
Stat. 452–453 (making it a federal crime “ `to transfer or possess a
machinegun' ”).
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433
Sotomayor, J., dissenting
though the rife automatically loads a new cartridge into the
chamber
after it is fred, it fres only one shot each time the
shooter pulls the trigger. See 18 U. S. C. § 921(a)(29) (2018
ed., Supp. IV).
To fre an M16 or AR–15 rife, a person typically holds the
“grip” next to the trigger with his fring hand. He stabilizes
the weapon with his other hand on its barrel or “front grip.”
He then raises the weapon so that the butt, or “stock,” of the
gun rests against his shoulder, lines up the sights to look
down the gun, and squeezes the trigger. See Dept. of the
Ar my, Field Manua l 23 – 9, Rifle Marksmansh ip M16A1,
M16A2/3, M16A4, and M4 Carbine, Ch. 4, Section III, p. 4–
22 (Sept. 13, 2006) (M16 Field Manual). A regular person
with an AR–15 can achieve a fre rate of around 60 rounds
per minute, with one pull of the trigger per second. Tr. of
Oral Arg. 39. A professional sport shooter can use the AR–
15 to fre at a rate of up to 180 rounds per minute, pulling
the trigger three times per second. Giffords Brief 14.
A shooter can also manually “bump” an AR–15 to increase
the rate of fre by using a belt loop or rubber band to hold
his trigger fnger in place and harness the recoil from the
frst shot to fre the rife continuously. See 83 Fed. Reg.
66532–66533 (2018). To use a belt loop, he must hold the
rife low against his hip, put his fnger in the trigger guard,
and then loop his fnger through a belt loop on his pants to
lock the fnger in place. See id., at 66533. With his other
hand, he then pushes the rife forward until his stationary
fnger engages the trigger to fre the frst shot. See ibid.
The recoil from that shot pushes the rife violently backward.
See ibid. If the shooter keeps pressing the rife forward
against the fnger in his belt loop, the repeated backward
jump of the recoil combined with his forward pressure allows
the rife to fre continuously. See ibid. A shooter using
this method, however, cannot shoot very precisely. He has
neither the advantage of the sights to line up his shot, nor
his shoulder to stabilize the recoil. A shooter can also use
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v. CARGILL
Sotomayor, J., dissenting
a rubber band or zip tie to tie a fnger close to the trigger.
See
id., at 66532. If the shooter is strong and skilled enough
physically to control the distance and direction of the rife's
signifcant recoil, the rife will fre continuously.
A bump stock automates and stabilizes the bump fring
process. It replaces a rife's standard stock, which is the
part held against the shoulder. See id., at 66516. A bump
stock, unlike a standard stock, allows the rife's upper assem-
bly to slide back and forth in the stock. See ibid. It also
typically includes a fnger rest on which the shooter can place
his fnger while shooting, and a “receiver module” that
guides and regulates the weapon's recoil. Ibid. To fre a
semiautomatic rife equipped with a bump stock, the shooter
either pulls the trigger, see ibid., or slides the gun forward
in the bump stock, which presses the trigger into his trigger
fnger, Cargill v. Barr, 502 F. Supp. 3d 1163, 1175 (WD Tex.
2020). As long as the shooter keeps his trigger fnger on
the fnger rest and maintains constant forward pressure on
the rife's barrel or front grip, the weapon will fre continu-
ously. See 83 Fed. Reg. 66516. A rife equipped with a
bump stock can fre at a rate between 400 and 800 rounds
per minute. Tr. of Oral Arg. 40.
II
A machinegun does not fre itself. The important ques-
tion under the statute is how a person can fre it. A weapon
is a “machinegun” when a shooter can (1) “by a single func-
tion of the trigger,” (2) shoot “automatically more than one
shot, without manually reloading.” 26 U. S. C. § 5845(b).
The plain language of that defnition refers most obviously to
a rife like an M16, where a single pull of the trigger provides
continuous fre as long as the shooter maintains backward
pressure on the trigger. The defnition of “machinegun”
also includes “any part designed and intended . . . for use in
converting a weapon into a machinegun.” Ibid. That lan-
guage naturally covers devices like bump stocks, which “con-

Cite
as: 602 U. S. 406 (2024)
435
Sotomayor, J., dissenting
ver[t]” semiautomatic rifes so that a single pull of the trig-
ger
provides continuous fre as long as the shooter maintains
forward pressure on the gun.
This is not a hard case. All of the textual evidence points
to the same interpretation. A bump-stock-equipped semi-
automatic rife is a machinegun because (1) with a single pull
of the trigger, a shooter can (2) fre continuous shots without
any human input beyond maintaining forward pressure.
The majority looks to the internal mechanism that initiates
fre, rather than the human act of the shooter's initial pull,
to hold that a “single function of the trigger” means a reset
of the trigger mechanism. Its interpretation requires six
diagrams and an animation to decipher the meaning of the
statutory text. See ante, at 417–421, and n. 5. Then, shift-
ing focus from the internal mechanism of the gun to the
perspective of the shooter, the majority holds that continu-
ous for ward pressure is too much human i nput for
bump-stock-enabled continuous fre to be “automatic.” See
ante, at 424–427.
The majority's reading fies in the face of this Court's
standard tools of statutory interpretation. By casting aside
the statute's ordinary meaning both at the time of its
enactment and today, the majority eviscerates Congress's
regulation of machineguns and enables gun users and manu-
facturers to circumvent federal law.
A
Start with the phrase “single function of the trigger.” All
the tools of statutory interpretation, including dictionary
defnitions, evidence of contemporaneous usage, and this
Court's prior interpretation, point to that phrase meaning
the initiation of the fring sequence by an act of the shooter,
whether via a pull, push, or switch of the fring mechanism.
The majority nevertheless interprets “ `function of the trig-
ger' ” as “the mode of action by which the trigger activates
the fring mechanism.” Ante, at 416. Because in a bump-
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436 GARLAND
v. CARGILL
Sotomayor, J., dissenting
stock-equipped semiautomatic rife, the trigger's internal
mechanism
must reset each time a weapon fres, the majority
reads each reset as a new “function.” That reading fxates
on a frearm's internal mechanics while ignoring the human
act on the trigger referenced by the statute.
Consider the relevant dictionary defnitions. In 1934,
when Congress passed the National Firearms Act, “function”
meant “the mode of action by which [something] fulfls its
purpose.” 4 Oxford English Dictionary 602 (1933). A
“trigger” meant the “movable catch or lever” that “sets
some force or mechanism in action.” 11 id., at 357. The
majority agrees with those defnitions. Ante, at 415–416.
It errs, however, by maintaining a myopic focus on a trig-
ger's mechanics rather than on how a shooter uses a trigger
to initiate fre. Ante, at 416.
Nothing about those defnitions suggests that “function of
the trigger” means the mechanism by which the trigger re-
sets mechanically to fre a second shot. See ante, at 416–
421 (explaining the interior mechanics of an AR–15 trigger
mechanism), as opposed to the process that a pull of the trig-
ger on a bump-stock-equipped semiautomatic rife sets in mo-
tion. The most important “function” of a “trigger” is what
it enables a shooter to do; what “force or mechanism” it sets
“in action.” 11 Oxford English Dictionary, at 357. A “sin-
gle function of the trigger” more naturally means a single
initiation of the fring sequence. Regardless of what is hap-
pening in the internal mechanics of a frearm, if a shooter
must activate the trigger only a single time to initiate a fr-
ing sequence that will shoot “automatically more than one
shot,” that frearm is a “machinegun.” § 5845(b).
Evidence of contemporaneous usage overwhelmingly sup-
ports that interpretation. The term “ `function of the trig-
ger' ” was proposed by the president of the National Rife
Association (NRA) during a hearing on the National Fire-
arms Act before the House. See National Firearms Act:
Hearings on H. R. 9066 before the House Committee on Ways
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as: 602 U. S. 406 (2024)
437
Sotomayor, J., dissenting
and Means, 73d Cong., 2d Sess., 38–40 (1934). He under-
stood
the “distinguishing feature of a machine gun [to be]
that by a single pull of the trigger the gun continues to fre.”
Id., at 40. He emphasized that a frearm “which is capable
of fring more than one shot by a single pull of the trigger, a
single function of the trigger, is properly regarded . . . as a
machine gun.” Ibid. Distinguishing a machinegun from a
pistol, the NRA president emphasized that for a pistol “[y]ou
must release the trigger and pull it again for the second shot
to be fred.” Id., at 41. He did not say “the hammer slips
off the disconnector just as the square point of the trigger
rises into the notch on the hammer . . . thereby reset[ting
the trigger mechanism] to the original position.” Ante, at
420–421. He instead emphasized the action of the shooter,
who must repeatedly activate the trigger for each shot.
Predictably, the House and Senate Reports refect the same
understanding of the phrase. See H. R. Rep. No. 1780, 73d
Cong., 2d Sess., 2 (1934) (reporting that the statute “contains
the usual defnition of machine gun as a weapon designed to
shoot more than one shot without reloading and by a single
pull of the trigger”); S. Rep. No. 1444, 73d Cong., 2d Sess.,
2 (1934) (same).
The majority cannot disregard these statements as evi-
dence of legislative purpose.
2
They are, along with contem-
poraneous dictionary defnitions, some of the best evidence of
contemporaneous understanding. Cf. McDonald v. Chicago,
561 U. S. 742, 828 (2010) (Thomas, J., concurring in part and
concurring in judgment) (“Statements by legislators can as-
sist . . . to the extent they demonstrate the manner in which
the public used or understood a particular word or phrase”).
Indeed, at oral argument, when asked what evidence there
was “that as of 1934, the ordinary understanding of the
2
Of course, “authoritative legislative history can be useful, even when
the meaning can be discerned from the statute's language, to reinforce or
to confrm a court's sense of the text.” R. Katzmann, Judging Statutes
35 (2014).
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438 GARLAND
v. CARGILL
Sotomayor, J., dissenting
phrase `function of the trigger' referred to the mechanics of
the
gun rather than . . . the shooter's motion,” respondent's
lawyer could not point to a single piece of evidence that sup-
ports the majority's reading. Tr. of Oral Arg. 98; see id.,
at 98–101. He even agreed that Congress used the word
“function” to ensure that the statute covered a wide variety
of trigger mechanisms, including both push and pull triggers.
Id., at 101–102. In short, the majority disregards the unre-
futed evidence of the text's ordinary and contemporaneous
meaning, substituting instead its own understanding of the
internal mechanics of an AR–15 without looking at the ac-
tions of the shooter.
This Court itself has also previously read the defnition of
“machinegun” in this exact statute to refer to the action of
the shooter rather than the fring mechanism. In Staples v.
United States, 511 U. S. 600 (1994), the Court noted that “a
weapon that fres repeatedly with a single pull of the trig-
ger” is a machinegun, as opposed to “a weapon that fres only
one shot with each pull of the trigger,” which is (at most) a
semiautomatic frearm. Id., at 602, n. 1 (emphasis added).
A “pull” of the trigger necessarily requires human input.
W hen a shooter i nitiates the fir i ng sequence on a
bump-stock-equipped semiautomatic rife, he does so with “a
single function of the trigger” under that term's ordinary
meaning. Just as the shooter of an M16 need only pull the
trigger and maintain backward pressure (on the trigger), a
shooter of a bump-stock-equipped AR–15 need only pull the
trigger and maintain forward pressure (on the gun). Both
shooters pull the trigger only once to fre multiple shots.
The only difference is that for an M16, the shooter's back-
ward pressure makes the rife fre continuously because of
an internal mechanism: The curved lever of the trigger does
not move. In a bump-stock-equipped AR–15, the mecha-
nism for continuous fre is external: The shooter's forward
pressure moves the curved lever back and forth against his
stationary trigger fnger. Both rifes require only one initial

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as: 602 U. S. 406 (2024)
439
Sotomayor, J., dissenting
action (that is, one “single function of the trigger”) from the
shooter
combined with continuous pressure to activate con-
tinuous fre.
3
The majority resists this ordinary understanding of the
term “function of the trigger” with two technical argu-
ments.
4
First, it attempts to contrast the action required to
fre an M16 from that required to fre a bump-stock-equipped
AR–15. The majority argues that “holding the trigger
down on a fully automatic rife is not manual input in addition
to a trigger's function—it is what causes the trigger to func-
tion in the frst place” whereas “pushing on the front grip [of
a bump-stock equipped semiautomatic rife] will not cause
the weapon to fre unless the shooter also engages the trig-
ger with his other hand.” Ante, at 425. The shooter of a
bump-stock-equipped AR–15, however, need not “pull” the
trigger to fre. Instead, he need only place a fnger on the
fnger rest and push forward on the front grip or barrel with
his other hand. Instead of pulling the trigger, the forward
motion pushes the bump stock into his fnger.
Second, the majority tries to cabin “single function of
the trigger” to a single mechanism for activating continuous
fre. See ante, at 424–425. A shooter can fre a bump-stock-
3
The majority thinks that this logic should apply just as well to manual
bump fring. Ante, at 423. As described supra, at 433–434, and in fra, at
441–442, however, bump fring requires much more from the shooter than
the simple forward pressure required to fre a bump-stock-equipped semi-
automatic rife.
4
The majority claims that these arguments explain only “why, even as-
suming a semiautomatic rife equipped with a bump stock could fre more
than one shot by a single function of the trigger, it could not do so `auto-
matically.' ” Ante, at 422, n. 6. That is correct, as far as the majority's
reasoning goes. The majority defnes “ `single function of the trigger' ”
as a reset of a rife's internal trigger mechanism. Ante, at 421. A more
accurate defnition is the human action required to initiate the fring se-
quence. Supra, at 435–439. The majority's argument for why “some-
thing more than a `single function of the trigger' is required to fre multi-
ple shots,” ante, at 424, is therefore relevant to both its discussion of
“automatically” and my discussion of “single function of the trigger.”

440 GARLAND
v. CARGILL
Sotomayor, J., dissenting
equipped semiautomatic rife in two ways. First, he can
choose
to fre single shots via distinct pulls of the trigger
without exerting any additional pressure. Second, he can
fre continuously via maintaining constant forward pressure
on the barrel or front grip. The majority holds that the for-
ward pressure cannot constitute a “single function of the
trigger” because a shooter can also fre single shots by pull-
ing the trigger. That logic, however, would also exclude a
Tommy Gun and an M16, the paradigmatic examples of regu-
lated machineguns in 1934 and today. Both weapons can fre
either automatically or semiautomatically. A shooter using
a Tommy Gun in automatic mode could choose to fre single
shots with distinct pulls of the trigger, or continuous shots
by maintaining constant backward pressure on the trigger.
See supra, at 431. An M16 user can toggle the weapon from
semiautomatic mode, which allows only one shot per pull of
the trigger, to automatic mode, which enables continuous
fre. See M16 Field Manual, Ch. 4, Section III, p. 4–8. In
1934 as now, there is no commonsense difference between a
frearm where a shooter must hold down a trigger or fip a
switch to initiate rapid fre and one where a shooter must
push on the front grip or barrel to do the same.
The majority's logic simply does not overcome the over-
whelming textual and contextual evidence that “single func-
tion of the trigger” means a single action by the shooter
to initiate a fring sequence, including pulling a trigger and
pushing forward on a bump-stock-equipped semiautomatic
rife.
B
Next, consider what makes a machinegun “automatic.” A
bump-stock-equipped semiautomatic rife is a “machinegun”
because with a “single function of the trigger” it “shoot[s],
automatically more than one shot, without manual reload-
ing.” § 5845(b). Put simply, the bump stock automates the
process of fring more than one shot.
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Cite
as: 602 U. S. 406 (2024)
441
Sotomayor, J., dissenting
Before automatic weapons, a person who wanted to fre
mu
ltiple shots from a frearm had to do two things after pull-
ing the trigger the frst time: (1) he had to reload the gun;
and (2) he had to pull the trigger again. A semiautomatic
weapon like an AR–15 already automates the frst process.
The bump stock automates the second.
5
In a fully automatic
rife like an M16, that automation is internal. After a
shooter pulls the trigger, if he maintains continuous back-
ward pressure on the trigger, the curved lever itself will not
move. Instead, an internal mechanism allows continuous
fre. On a bump-stock-equipped semiautomatic rife, the au-
tomation is external. After a shooter pulls the trigger, if he
maintains continuous forward pressure on the gun, the bump
stock harnesses the recoil to move the curved lever back and
forth against his fnger. That external automated motion
creates continuous fre.
When a shooter “bump” fres a semiautomatic weapon
without a bump stock, he must control several things using
his own strength and skill: (1) the backward recoil of each
shot, including both the direction in which the rife moves
and how far it moves when recoiling; (2) the trigger fnger,
by maintaining a stationary position with a loose enough hold
on the trigger that the rapidly moving gun will hit his fnger
each time; and (3) the forward motion of the rife after it
recoils backward. A bump stock automates those processes.
The replacement stock controls the direction and distance of
the recoil, and the fnger rest obviates the need to maintain
5
The majority attempts to analogize a bump stock to the Model 37 shot-
gun, which allows the user to “fre multiple shots by holding down the
trigger while operating the shotgun's pump action.” Ante, at 425. The
Model 37 automates the second process (i.e., pulling the trigger for each
shot), as long as the shooter maintains pressure on the trigger. Unlike a
semiautomatic rife, however, the Model 37 does not automate the frst, as
the shooter “must manually operate the pump action with his nontrigger
hand” to “ejec[t] the spent cartridge and loa[d] a new one into the cham-
ber.” Ante, at 425–426.

442 GARLAND
v. CARGILL
Sotomayor, J., dissenting
a stationary fnger position. All a shooter must do is rest
h
is fnger and press forward on the front grip or barrel for
the rife to fre continuously.
The majority nevertheless concludes that a bump-stock-
equipped semiautomatic rife requires too much human input
to fire “ `automatically' ” because it requires the “proper
amount of forward pressure on the front grip” to maintain
continuous fre. Ante, at 426. “Automati[c],” however, does
not mean zero human input. An M16 requires the shooter
to exert the “proper amount of [backward] pressure on the”
trigger to maintain continuous fre. Ibid. So, too, a ma-
chinegun that requires a user to hold down a button. Mak-
ers of automatic weapons may require continuous human
input for safety purposes; an accidental trigger pull that acti-
vates rapid fre is less harmful if it does not require affrma-
tive human action to stop. Requiring continuous pressure
for continuous fre, however, does not prevent a frearm from
“shoot[ing], automatically more than one shot.” § 5845(b).
C
This Court has repeatedly avoided interpretations of a
statute that would facilitate its ready “evasion” or “enable
offenders to elude its provisions in the most easy manner.”
The Emily, 9 Wheat. 381, 389–390 (1824); see also Abramski
v. United States, 573 U. S. 169, 181–182, 185 (2014) (declining
to read a gun statute in a way that would permit ready “eva-
sion,” “defeat the point” of the law, or “easily bypass the
scheme”). Justice Scalia called this interpretive principle
the “presumption against ineffectiveness.” A. Scalia & B.
Garner, Reading Law: The Interpretation of Legal Texts 63
(2012). The majority arrogates Congress's policymaking
role to itself by allowing bump-stock users to circumvent
Congress's ban on weapons that shoot rapidly via a single
action of the shooter.
“The presumption against ineffectiveness ensures that a
text's manifest purpose is furthered, not hindered.” Ibid.
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as: 602 U. S. 406 (2024)
443
Sotomayor, J., dissenting
Before machineguns, a shooter could fre a gun only as fast
as
his fnger could pull the trigger. Congress sought to re-
strict the civilian use of machineguns because they elimi-
nated the need for a person rapidly to pull the trigger him-
self to fre continuously. A bump stock serves that function.
Even a skilled sport shooter can fre an AR–15 at a rate of
only 180 rounds per minute by rapidly pulling the trigger.
Anyone shooting a bump-stock-equipped AR–15 can fre at a
rate between 400 and 800 rounds per minute with a single
pull of the trigger.
Moreover, bump stocks are not the only devices that trans-
form semiautomatic rifes into weapons capable of rapid fre
with a single function of the trigger. Recognizing the cre-
ativity of gun owners and manufacturers, Congress wrote a
statute “loaded with anticircumvention devices.” Tr. of
Oral Arg. 68. The defnition of “machinegun” captures “any
weapon which shoots, is designed to shoot, or can be readily
restored to shoot, automatically more than one shot, with-
out manual reloading, by a single function of the trigger.”
§ 5845(b). Not “more than four, fve, or six shots,” not “sin-
gle pull” or “single push” of the trigger. Following that
defnition, the Bureau of Alcohol, Tobacco, Firearms and Ex-
plosives (ATF) has reasonably classifed many transforma-
tive devices other than bump stocks as “machinegun[s].”
6
For instance, ATF has long classifed “forced reset triggers”
as machineguns. See Brief for Petitioners 28. A forced
6
The majority emphasizes that ATF previously took the position that
certain bump-stock devices were not “machinegun[s]” under the statute.
See ante, at 412, 428. ATF, however, has repeatedly classifed other de-
vices that modify semiautomatic rifes by allowing a single activation of
the shooter to automate repeat fre as machineguns. See, e.g., 83 Fed.
Reg. 66518, n. 4 (referencing ATF classifcations of trigger reset devices);
Akins v. United States, 312 Fed. Appx. 197, 200–201 (CA11 2009) (per cu-
riam) (upholding classifcation of Akins Accelerator, a spring-operated
bump stock); United States v. Camp, 343 F. 3d 743, 745 (CA5 2003) (uphold-
ing classifcation of fshing reel attached to a rife trigger that, upon activa-
tion, repeatedly operated the curved lever of the rife).
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444 GARLAND
v. CARGILL
Sotomayor, J., dissenting
reset trigger includes a device that forces the trigger back
downward
after the shooter's initial pull, repeatedly pushing
the curved lever against the shooter's stationary trigger
fi nger. See ib i d. To a shooter, a semiautomatic r ifle
equipped with a forced reset trigger feels much like an M16.
He must pull the trigger only once and then maintain pres-
sure to achieve continuous fre. See ibid.
Gun owners themselves also have built motorized devices
that will repeatedly pull a semiautomatic frearm's curved
lever to enable continuous fre. ATF has classifed such de-
vices as “machinegun[s]” since 1982. See Record 1077. In
2003, the Fifth Circuit held that such a contraption qualifed
as a “machinegun” under the statute. See United States v.
Camp, 343 F. 3d 743, 745. An owner of a semiautomatic rife
had placed a fshing reel inside the weapon's trigger guard.
Id., at 744. When he pulled a switch behind the original
trigger, the switch supplied power to a motor connected to
the fshing reel. Ibid. The motor caused the reel to rotate,
and that rotation manipulated the curved lever, causing it to
fre in rapid succession. Ibid. ATF in 2017 also classifed
as a “machinegun” a wearable glove that a shooter could acti-
vate to initiate a mechanized piston moving back and forth,
repeatedly pulling and releasing a semiautomatic rife's
curved lever. See Record 1074–1076.
7
The majority tosses aside the presumption against ineffec-
tiveness, claiming that its interpretation only “draws a line
more narrowly than one of [Congress's] conceivable statutory
purposes might suggest” because the statute still regulates
7
Respondent does not today challenge ATF's classifcation of these de-
vices as “machinegun[s].” His lawyer noted at oral argument, however,
that “forced reset triggers” would be part of a category of “harder cases”
where “there may be a question as to what exactly the trigger is and then
how does that trigger function.” Tr. of Oral Arg. 82. That ambiguity
stems from the majority's loophole for weapons that require multiple me-
chanical actions to fre continuously, even when a shooter initiates that fre
with a single human action.

Cite
as: 602 U. S. 406 (2024)
445
Sotomayor, J., dissenting
“all traditional machineguns” like M16s. Ante, at 427.
Congress'
s ban on M16s, however, is far less effective if a
shooter can instead purchase a bump stock or construct a
device that enables his AR–15 to fre at the same rate. Even
bump-stock manufacturers recognize that they are exploiting
a loophole, with one bragging on its website “Bumpfre Stocks
are the closest you can get to full auto and still be legal.” Mid-
south Shooters, BUMPFIRE SYSTEMS, https://www.
midsouthshooterssupply.com/ b/ bumpfre-systems. The ma-
jority creates a defnition of the statute that bans only “tradi-
tional” machineguns, even though its defnition renders Con-
gress's clear intent readily evadable.
Every Member of the majority has previously emphasized
that the best way to respect congressional intent is to adhere
to the ordinary understanding of the terms Congress uses.
See, e.g., Jam v. International Finance Corp., 586 U. S. 199,
209 (2019) (Roberts, C. J., for the Court) (“ ‘[T]he legislative
purpose is expressed by the ordinary meaning of the words
used' ”); Gross v. FBL Financial Services, Inc., 557 U. S. 167,
175 (2009) (Thomas, J., for the Court) (“ `Statutory construc-
tion must begin with the language employed by Congress
and the assumption that the ordinary meaning of that lan-
guage accurately expresses the legislative purpose' ”); Wall
v. Kholi, 562 U. S. 545, 551 (2011) (Alito, J., for the Court)
(“ `We give the words of a statute their ordinary, contempo-
rary, common meaning, absent an indication Congress in-
tended them to bear some different import' ”); BP p.l.c. v.
Mayor and City Council of Baltimore, 593 U. S. 230, 237
(2021) (Gorsuch, J., for the Court) (“When called on to inter-
pret a statute, this Court generally seeks to discern and
apply the ordinary meaning of its terms at the time of their
adoption”); Sackett v. EPA, 598 U. S. 651, 723, 727 (2023)
(Kavanaugh, J., concurring in judgment) (reasoning that de-
parting from “all indications of ordinary meaning ” will “cre-
ate regulatory uncertainty for the Federal Government . . .
and regulated parties”); Bartenwerfer v. Buckley, 598 U. S.
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446 GARLAND
v. CARGILL
Sotomayor, J., dissenting
69, 77, 83 (2023) (Barrett, J., for the Court) (declining to
“ar
tifcially narrow ordinary meaning ” to “second-guess
[Congress's] judgment”). Today, the majority forgets that
principle and substitutes its own view of what constitutes a
“machinegun” for Congress's.
***
Congress's defnition of “machinegun” encompasses bump
stocks just as naturally as M16s. Just like a person can
shoot “automatically more than one shot” with an M16
through a “single function of the trigger” if he maintains
continuous backward pressure on the trigger, he can do the
same with a bump-stock-equipped semiautomatic rife if he
maintains forward pressure on the gun. § 5845(b). Today's
decision to reject that ordinary understanding will have
deadly consequences. The majority's artificially narrow
defnition hamstrings the Government's efforts to keep ma-
chineguns from gunmen like the Las Vegas shooter. I re-
spectfully dissent.
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Reporter’s Note
The attached opinion has been revised to refect the usual publication
and citation style of the United States Reports. The revised pagination
makes available the offcial United States Reports citation in advance of
publication. The syllabus has been prepared by the Reporter of Decisions
for the convenience of the reader and constitutes no part of the opinion of
the Court. A list of counsel who argued or fled briefs in this case, and
who were members of the bar of this Court at the time this case was
argued, has been inserted following the syllabus. Other revisions may
include adjustments to formatting, captions, citation form, and any errant
punctuation. The following additional edits were made:
p. 407, line 12 from bottom: “trigger” is replaced with “fnger”
p. 423, line 3 from bottom: “a” is inserted after “that”
p. 432, line 2 from bottom: “assault” is deleted