February 12, 2021
Handguns, Stabilizing Braces, and Related Components
On December 18, 2020, the Bureau of Alcohol, Tobacco,
the trigger pad to the end of the cheek rest fully extended).
Firearms and Explosives (ATF) published guidance in the
The defendant was found not guilty by a jury, based partly
for public comment that indicated that it
on ATF’s failure to take the measurement properly in
was preparing to reclassify certain heavier, larger
alignment with the barrel’s axis. This case is an example of
handguns (pistols) equipped with stabilizing braces
how the absence of definitive determinations about the
more stringently regulated short-barreled rifles
. Such a
legality of firearms equipped with stabilizing braces and
reclassification would have retroactively triggered the more
similar devices may create repercussions.
extensive paperwork and background check requirements of
the 1934 National Firearms Act (NFA), and required
GCA- and NFA-Regulated Firearms
registration of the owner and firearm with ATF. On
When Congress passed the GCA, it significantly amended
December 23, 2020, however, ATF withdrew its guidance,
and repassed the NFA as Title II of that measure. These acts
pending further Department of Justice review.
include different, but respective definitions for the term
“firearm” (18 U.S.C. §921(a)(3) and 26 U.S.C. §5845(a)).
Stabilizing Brace: Shooter’s Assist or
Under these definitions, all firearms regulated under the
NFA are first regulated under the GCA. As discussed
Stabilizing braces are devices that can be attached to the
below, the three basic types of firearms regulated under the
rearward portion (breech) of a handgun or other pistol grip
GCA are shotguns, rifles, and handguns.
firearm’s frame or receiver. The brace extends backwards,
generally in alignment with the axis of the barrel(s), so the
SBSs, SBRs, AOWs, and DDs
firearm can be secured to the shooter’s forearm, while it is
The NFA further regulates short-barreled shotguns, or
held by its pistol grip or other short stock, making a
SBSs, and short-barreled rifles, or SBRs: (1) shotguns with
heavier, larger short-stocked firearm easier to handle. The
barrels less than 18 inches in length, (2) rifles with barrels
first prototype stabilizing brace was designed to assist a
less than 16 inches in length, or (3) any existing shotgun or
veteran and service-connected amputee with firing an AR-
rifle that has been modified to be less than 26 inches in
type handgun singlehandedly.
overall length by shortening its stock and/or barrel(s). (See
18 U.S.C. §§921(a)(6) and (8), and 26 U.S.C. §5845(a).)
Stabilizing braces and similar devices, however, could
serve more generally as a quasi-shoulder stock. The
Under “any other weapon,” or AOW, the NFA regulates
addition of shoulder stock to a short-stocked firearm could
smoothbore handguns (less than 26 inches in overall length)
possibly change a firearm’s classification under current law
and other “concealable” firearms with combination
due to definitional differences between the NFA and Gun
smoothbore and rifled bore barrels between 12 and 18
Control Act of 1968 (GCA).
inches in length. The AOW classification also captures
certain deceptive or disguised firearms (e.g., umbrella, belt
ATF has long ruled that the attachment of a shoulder stock
buckle, and pen guns). The term “any other weapon” is
to a handgun or pistol grip firearm transformed that GCA-
defined at 26 U.S.C. §5845(e).
regulated firearm into an NFA-regulated short-barreled rifle
or shotgun. In November 2012, however, ATF determined
Under “destructive device,” or DD, the NFA regulates
that attaching a stabilizing brace to an AR-type pistol would
“non-sporting” shotguns; firearms with barrel bore
not change that firearm’s classification from a solely GCA-
diameters greater than one-half inch (e.g., grenade
regulated handgun to an NFA-regulated short-barreled rifle.
launchers, bazookas, and mortars); as well as grenades,
Since then, many variations of stabilizing braces have been
rockets, mortar rounds, mines, and other explosive devices
manufactured and sold in the United States.
(e.g., Molotov cocktails). Congress included similar
definitions for the term “destructive device” in the GCA
In 2015, in an Open Letter, ATF raised questions as to the
and NFA (18 U.S.C. §921(a)(4) and 26 U.S.C. §5845(f)). In
legality of using or intending to use stabilizing braces as
addition, the NFA regulates machine guns and firearms
shoulder stocks. In several private letters, made public by
silencers, which are beyond the scope of this In Focus.
the addressees, ATF appeared to walk back these
considerations. In 2018, however, ATF charged an
Shotgun and Rifle Definitions
individual with unlawfully possessing an unregistered
Congress included identical statutory standalone definitions
short-barreled rifle—an AR-type pistol equipped with a
for the terms “shotgun” and “rifle” under the GCA and
cheek rest, which is arguably a variant of a stabilizing
NFA. The term “shotgun” means “a weapon designed or
brace. ATF submitted that this cheek rest, when fully
redesigned, made or remade, and intended to be fired from
extended, constituted a shoulder stock, because its “length
the shoulder and designed or redesigned and made or
of pull” was greater than 13.5 inches (i.e., the distance from
remade to use the energy of an explosive to fire through a
Handguns, Stabilizing Braces, and Related Components
smooth bore either a number of ball shot or a single
trigger the NFA requirements, as long as a shoulder stock is
projectile for each single pull of the trigger” (18 U.S.C.
never affixed to its frame or receiver.
§921(a)(5) and 26 U.S.C. §5845(d)). The term “rifle”
means “a weapon designed or redesigned, made or remade,
The same is true for pistol grip firearms. However, ATF
and intended to be fired from the shoulder and designed or
holds out the possibility of reclassifying pistol grip firearms
redesigned and made or remade to use the energy of an
as AOWs under the NFA if they are ever used in a
explosive to fire only a single projectile through a rifled
concealed manner in the commission of a crime. Others
bore for each single pull of the trigger” (18 U.S.C.
counter that pistol grip firearms would be more properly
§921(a)(7) and 26 U.S.C. §5845(c)).
classified as DDs, under ATF’s reasoning that these short-
stocked, smoothbore firearms are “non-handguns” and
From these definitions, it can be deduced that the defining
“non-shotguns,” and are usually firearms with barrel bores
characteristic of a long gun (shotgun or rifle) is that it is
of greater than one-half inch in diameter.
intended to be shoulder-fired, from which it follows that the
defining feature of a long gun is a shoulder stock
Larger, Heavier Handguns, and Pistol
type. In addition, shotguns are “smoothbore.” The barrel of
a rifle is “rifled bore,” and consists of lines and grooves
In the past 16 years, firearms manufacturers in the United
machine-cut into the interior of the barrel (the bore) to spin
States have successfully marketed certain larger, heavier
a bullet as it travels at a high velocity down the barrel bore.
handguns and other pistol grip firearms that arguably push
the limits of current law definitions of firearms types and
Handgun Definition and Other Pistol Grip Firearms
classes under current law. Some of these handguns are
Under the GCA, the term “handgun” means “(A) a firearm
assembled around frames and receivers originally designed
which has a short stock and is designed to be held and fired
for AR- and AK-type rifles, and are sometimes chambered
by the use of a single hand; and (B) any combination of
for mid-size rifle cartridges and shotgun shells.
parts from which a firearm described in subparagraph (A)
can be assembled” (18 U.S.C. §921(a)(29)). From this
Under the 1994-2004 Semiautomatic Assault Weapons
definition, it can be deduced that the defining feature of a
(SAW) ban, some of these handguns could have been
handgun is its short stock
, and that it is designed to be fired
prohibited under its 50 ounce weight limit (unloaded) and
singlehandedly. The term handgun includes both pistols and
other characteristics that defined an “assault pistol.” The
revolvers (26 C.F.R. §§478.11 and 479.11). Under current
SAW ban did not address pistol grip firearms substantively,
law, rifled bore handguns
are regulated solely under the
as many of these firearms were pump-action, as opposed to
GCA and there are no restrictions on the barrel or overall
semiautomatic, when the ban was enacted. The introduction
length of such handguns.
of stabilizing braces and similar components has
significantly increased the popularity of heavier, larger
are regulated under the NFA under
pistols and pistol grip firearms.
the AOW classification. Since at least 1976, however, ATF
has adopted 26 inches in overall length as the determining
In the past eight years, larger, heavier handguns and pistol
dimension that separates NFA-regulated “concealable”
grip firearms have seen increased sales likely due, in no
smoothbore handguns, or AOWs, from GCA-regulated
small part, to stabilizing braces. Most major firearms
short-stocked, smoothbore firearms. ATF adopted this
manufacturers are making firearms equipped with
presumptive dimension of concealability from the statutory
stabilizing braces as part of their featured product lines.
definitions for short-barreled rifles and shotguns discussed
While there are no available statistics to gauge
above. ATF refers to these solely GCA-regulated short-
authoritatively the number of stabilizing braces already
stocked, smoothbore firearms, which are greater than 26
made and sold in the United States, unofficial estimates
inches in overall length, as “pistol grip firearms.”
suggest that there are between 10 and 40 million stabilizing
braces and similar components already in civilian hands,
The popularity of pistol grip firearms arguably increased in
either purchased as accessories or already attached to
2008, when ATF determined that the barrel length was
firearms made at home or at the factory. Altering the
“immaterial” to the classification of such firearms, while
classification of firearms equipped with stabilizing braces
the 26 inches in overall length restriction remained
would likely affect millions of owners.
unchanged. Prior to this, most firearms makers believed that
the barrel of a pistol grip firearm had to be greater than 18
Today, some firearms enthusiasts view GCA-regulated
handguns and pistol grip firearms equipped with stabilizing
braces as viable alternatives to the more strictly NFA-
“Gray Area” in the Law?
regulated short-barreled rifles and shotguns. At the same
In a potentially legal gray area, some GSA-regulated
time, gun control advocates have called on ATF to reverse
handguns and pistol grip firearms are dimensionally
its determinations with regard to stabilizing braces, as well
equivalent—in terms of their barrel lengths, overall lengths,
as, larger, heavier handguns and other pistol grip firearms.
and/or barrel bores—to other NFA-regulated firearms. As
They view such firearms as “assault pistols” or “assault
discussed above, it is unlawful to modify an existing rifle or
shotguns,” and have called on Congress to reconstitute an
shotgun by shortening its stock and/or barrel(s) into a short-
assault weapons ban.
barreled rifle or shotgun without following the NFA
requirements, which includes remitting a $200 making tax.
William J. Krouse
, Specialist in Domestic Security and
However, a handgun with equivalent dimensions does not
Handguns, Stabilizing Braces, and Related Components
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