Privately Made Firearms: A Growing Source of Unmarked, Untraceable “Ghost Guns”?

Privately Made Firearms: A Growing Source of Unmarked, Untraceable “Ghost Guns”?

April 8, 2021
Privately Made Firearms: A Growing Source of Unmarked,
Untraceable “Ghost Guns”?
On April 7, 2021, the White House announced that the
sets limits on building a firearm for one’s own use.
Department of Justice (DOJ) has been directed to issue a
Building a privately made firearm is only permissible if the
proposed rule to address “ghost guns” within 30 days (by
maker is not prohibited from possessing a firearm under
May 7, 2021). For many years, “privately made firearms”
federal or state law; the firearm is not regulated under the
did not appear to be a large source of crime guns. In the last
National Firearms Act of 1934 (e.g., a machine gun or
decade, however, the commercial availability of parts kits,
short-barreled shotgun); and the maker does not build it
unfinished firearms frames or receivers, and compact
with intent to sell it. Even so, privately made firearms may
computer numerical control (CNC) milling devices have
be lawfully transferred, as long as the unlicensed maker did
arguably made building some firearms simpler and less
not build it with the intent to sell it. The GCA does not
expensive. As privately made firearms have increased in
impose recordkeeping or background check requirements
number, it appears that the use of unmarked “ghost guns” in
on such transfers, unless they are interstate transfers to
shooting sprees, shootouts with police, and other crimes has
other unlicensed persons, in which case those transfers must
also increased. The Bureau of Alcohol, Tobacco, Firearms
go through an FFL in the state where the transferee resides.
and Explosives (ATF) has expressed concern about its
inability to trace such firearms.
Firearms Marking and Recordkeeping
Under GCA, firearm importers and manufacturers are
“Ghost Guns”
required to mark (engrave, cast, or stamp) the frame or
“Ghost guns” is a term used to refer to firearms encountered
receiver of any firearms they import and make with a serial
by law enforcement that are largely untraceable, because
number and other markings (e.g., model, caliber, and
they were assembled, legally or illegally, by someone other
importer or manufacturer’s name, city, state) (18 U.S.C.
than a federally licensed manufacturer and, therefore, were
§923(i) and 27 C.F.R. §478.92). It is a felony for any
not marked with a serial number and other identifying
person to transport, ship, or receive in interstate or foreign
features on their frames or receivers. In the last decade, the
commerce, any firearm that has had its serial number
increase of crimes committed with privately made,
removed, obliterated, or altered (18 U.S.C. §922(k)).
unmarked “ghost guns” suggests that persons prohibited
from receiving or possessing firearms have increasingly
All FFLs, moreover, are required to maintain records on
exploited the general availability of unfinished firearms
firearms transactions for at least 20 years and make those
frames and receivers, or “blanks,” to assemble firearms
records available to ATF under certain circumstances.
(which they otherwise may not have been able to purchase
When an FFL goes out of business, he or she must submit
lawfully). Others, sometimes with criminal intent, build
those records to ATF, but those records may only be
these firearms so they cannot be traced back to them.
searched by make, model, and serial number of a firearm,
as statutory provisions prohibit a national registry of
Some people also fear that criminals could use 3D-printers
firearms or owners. By querying these records, ATF can
and computer-aided design (CAD) files to produce firearm
sometimes trace the firearm’s chain of commerce from
frames or receivers in large quantities, creating a significant
importer/manufacturer to wholesaler/distributor and, from
source of illegally trafficked, untraceable firearms.
there, to the retailer, and to the first unlicensed, private
Criminals may also be able to use such technology to
purchaser of record. Through this process, ATF can
produce “undetectable” firearms made of mainly non-
sometimes establish at what point a firearm was diverted
metallic parts (plastic/polymer guns), which might pass
from legal to illegal channels of commerce, and identify
through metal detectors at security checkpoints undetected.
persons engaged in illegal gun trafficking and other crimes.
“Privately Made Firearms” Under the GCA
Undetectable Firearms
The Gun Control Act of 1968 (GCA; 18 U.S.C. §§921 et
The GCA prohibits the manufacture, importation, transfer,
seq.) requires all persons who are engaged in the business
or possession of any firearm that is not detectable to walk-
of importing, manufacturing, or dealing in firearms to be
through metal detectors calibrated to detect a security
federally licensed. These licensees are commonly referred
exemplar that resembles a handgun with the same
to as federal firearms licensees, or FFLs. However, the
electromagnetic signature as 3.7 ounces of stainless steel. It
GCA does not prohibit a person from making a firearm for
is notable that nothing in this provision requires that
his or her own personal use. Nor does it require any form of
signature be made from an operable part of the firearm. The
federal licensure to do so, or require that such firearms be
act also prohibits firearms that include major components
marked with a unique serial number and other maker marks,
(barrels, slides, cylinders, frames, or receivers) that do not
as is the case for all other firearms imported or
generate an accurate image when inspected with x-ray
manufactured by FFLs under the act. Nonetheless, the GCA
machines commonly used at airports (18 U.S.C. §922(p)).
https://crsreports.congress.gov

Privately Made Firearms: A Growing Source of Unmarked, Untraceable “Ghost Guns”?
Firearm Frame or Receiver
these aluminum or polymer castings much simpler.
Under the GCA, the term “firearm” means “any weapon
Instructional how-to videos are widely available on the
(including a starter gun) which will or is designed to or may
internet. Today, individuals with a modicum of mechanical
readily be converted to expel a projectile by the action of an
ability can finish an aluminum or polymer frame or receiver
explosive.” This multi-faceted definition also includes the
without a great deal of difficulty and, then, assemble a fully
“frame or receiver” of any such weapon (18 U.S.C.
operable firearm with aftermarket firearm parts.
§921(a)(3)). A firearm frame or receiver is “that part of a
firearm which provides housing for the hammer, bolt or
Ghost Guns and High-Profile California Shootings
breechblock, and firing mechanism, and which is usually
While “ghost guns” are not a problem exclusive to
threaded at its forward portion to receive the barrel” (27
California, the issue rose to national prominence after
C.F.R. §478.11). A “receiver” is the central part of a rifle or
several high-profile mass shootings in that state. On June 7,
pistol to which the barrel and shoulder stock/grip(s) are
2013, an assailant went on a mass shooting spree in Santa
attached. In pistols, revolvers, and break-open firearms, this
Monica, CA, with an unmarked, semiautomatic AR-type
central part of a firearm is generally called a “frame.” The
semiautomatic rifle. On November 13-14, 2017, an
“receiver” or “frame” is generally the “controlled part” of a
assailant, who was already under a domestic violence
firearm. Transfers of fully manufactured, finished firearm
restraining order, went on a mass shooting spree in Tehama
frames or receivers are treated under the GCA in the same
County, CA, with a self-assembled, unmarked AR-type
way as a fully assembled firearm. Hence, a person must be
rifle. On November 14, 2019, a 16-year-old student shot
an FFL to import, manufacture, or deal in completed
several other students at Saugus High School, in Santa
firearm frames or receivers. FFLs may not sell finished
Clarita, CA, with an unmarked, semiautomatic pistol. In the
frames or receivers to anyone under 21 years of age, and
cases described above, all of the assailants were either
unlicensed purchasers of these items from FFLs are subject
prohibited persons or underage; that is, they were ineligible
to a GCA-required background check (18 U.S.C. §922(t)).
to receive or possess a firearm or ammunition under federal
law. In 2016, the California Legislature passed a law
Unfinished Frames or Receivers
requiring persons who assemble a rifle or shotgun for their
A federal license, however, is not required to manufacture
own use to acquire a unique serial number from the
or distribute incomplete, unfinished frames or receivers if
California Department of Justice. Privately made handguns
ATF has determined that these objects—in an unfinished
are prohibited under California law.
state of manufacture—do not meet the statutory definition
of a firearm. To finish them, one must drill out certain holes
Southwest Border Gun Trafficking
and hollow (mill) out the fire control cavity. These
In 2016, the Government Accountability Office (GAO)
unfinished objects are commonly referred to as “80%
reported that unfinished frames and receivers, as well as
frames and receivers,” but that descriptor does not reflect
other firearms parts (barrels, triggers, hammers, buttstocks,
any prescribed dimensions under federal law, and related
pistol grips, pins, bolts, and springs), were complicating law
ATF determinations are made largely on a case-by-case
enforcement efforts intended to prevent firearms from being
basis. Similarly, a federal license is not required to
unlawfully trafficked into Mexico. Arguably, a similar
manufacture or distribute other components necessary to
dynamic is playing out domestically on U.S. streets
build fully operable firearms, such as barrels, trigger or bolt
according to U.S. Attorney and ATF press releases. There
assemblies, magazines, grips, shrouds, muzzle brakes/flash
are also numerous press accounts of metropolitan police
suppressors, or any other firearm parts and accessories.
departments, including the District of Columbia, that report
significant increases in the numbers of “ghost guns” being
While unfinished steel frames for pistols and revolvers have
recovered by police.
been available for decades, these items usually required
additional finishing that required hobbyists to obtain the
FY2021 House Appropriations Language
services of a gunsmith or machinist. The popularity of
Currently, there are no definitive data on “ghost guns” as an
building a firearm from parts kits and unfinished frames
emerging national crime/public safety problem. In the 116th
and receivers increased after 1989, when the Bush
Congress, the House Committee on Appropriations reported
Administration imposed import restrictions on certain
its Commerce, Justice, Science, and Related Agencies
semiautomatic “military style” rifles and shotguns that were
Appropriations Act, 2021 (H.R. 7667) with accompanying
made statutory in 1990 (18 U.S.C. §922(r)). In part, FFLs
report language (H.Rept. 116-455, p. 81) that would have
responded to these restrictions by importing parts kits for
urged ATF to amend its definition of “firearm frame or
firearms like the AK-47. Licensed manufacturers and
receiver” under 27 C.F.R. §478.11 to ensure that privately
unlicensed, private persons then used those kits to build
manufactured firearms fall more fully under federal
firearms, though they were required to use a requisite
firearms regulations. Report language also directed ATF to
number of U.S.-made parts to fully assemble these firearms.
provide the committee with all available data on the rate
Other commercial producers provided unfinished receivers,
that federal authorities encounter ghost guns, and
or “flats,” that could be stamped or bent by pre-marked
recommendations to improve such data collection. This
folds, and drilled out by pre-marked holes, into a finished
report language, however, was not adopted as part of the
product. Parts kits and unfinished receivers, “castings,” for
Consolidated Appropriations Act, 2021 (P.L. 116-260).
AR-15-type firearms and many other firearms became
commercially available to the point they are commonplace
William J. Krouse, Specialist in Domestic Security and
on the U.S. civilian firearms market. In the past decade, jigs
Crime Policy
and templates have become available that make finishing
https://crsreports.congress.gov

Privately Made Firearms: A Growing Source of Unmarked, Untraceable “Ghost Guns”?

IF11810

Disclaimer
This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan shared staff to
congressional committees and Members of Congress. It operates solely at the behest of and under the direction of Congress.
Information in a CRS Report should not be relied upon for purposes other than public understanding of information that has
been provided by CRS to Members of Congress in connection with CRS’s institutional role. CRS Reports, as a work of the
United States Government, are not subject to copyright protection in the United States. Any CRS Report may be
reproduced and distributed in its entirety without permission from CRS. However, as a CRS Report may include
copyrighted images or material from a third party, you may need to obtain the permission of the copyright holder if you
wish to copy or otherwise use copyrighted material.

https://crsreports.congress.gov | IF11810 · VERSION 1 · NEW