IN THE UNITED STATES DISTRICT COURT

FOR THE NORTHERN DISTRICT OF TEXAS

FORT WORTH DIVISION

------------------------------------------------------- X

:

:

:

:

:

:

:

:

:

:

X

JENNIFER VANDERSTOK, et al.,

Plaintiffs,

v. 

MERRICK GARLAND, in his official 

capacity as Attorney General of the 

United States, et al.,

Defendants.

Civil Action No. 4:22-cv-00691-O

-------------------------------------------------------

BRIEF OF AMICI CURIAE GUN VIOLENCE PREVENTION GROUPS 

IN SUPPORT OF DEFENDANTS’ OPPOSITION TO PLAINTIFFS’ MOTION 

FOR PRELIMINARY INJUNCTION

DANIEL GROOMS*

Counsel of Record

MATT K. NGUYEN*

COOLEY LLP

1299 Pennsylvania Avenue, NW

Washington, DC 20004

Telephone: (202) 842-7800

dgrooms@cooley.com

mnguyen@cooley.com

* Pro hac vice pending

August 30, 2022

ADAM M. KATZ*

RACHEL H. ALPERT*

COOLEY LLP

500 Boylston Street

Boston, MA 02116

Telephone: (617) 937-2300

akatz@cooley.com

ralpert@cooley.com 

Counsel for Amici Curiae Gun Violence Prevention Groups

Case 4:22-cv-00691-O Document 59 Filed 09/08/22 Page 1 of 31 PageID 768
TABLE OF CONTENTS

i

DISCLOSURE STATEMENT................................................................................................. 1

STATEMENT OF INTEREST ..................................................................................... 1

INTRODUCTION ......................................................................................................... 2

ARGUMENT................................................................................................................. 6

I. THE RULE FAITHFULLY IMPLEMENTS THE GUN 

CONTROL ACT AND PREVENTS ITS SUBVERSION....................... 6

A. The Rule Implements the Act’s Clear Definition of 

“Firearm.”...................................................................................... 6

B. The Rule Advances the Act’s Purpose. ........................................ 8

II. THE RULE APPROPRIATELY CONSIDERS THE PRACTICAL 

REALITY THAT GHOST GUNS CAN BE QUICKLY AND 

EASILY ASSEMBLED BY NONEXPERTS......................................... 16

III. THE RULE COMPORTS WITH ATF’S LONGSTANDING VIEW 

THAT PARTIALLY COMPLETE FRAMES AND RECEIVERS 

CAN BE FIREARMS............................................................................. 20

CONCLUSION............................................................................................................ 24

CERTIFICATE OF SERVICE.................................................................................... 25

Case 4:22-cv-00691-O Document 59 Filed 09/08/22 Page 2 of 31 PageID 769
TABLE OF AUTHORITIES

Page(s)

ii

Cases

Abramski v. United States,

573 U.S. 169 (2014) ...................................................................................... 2, 11, 13

Barrett v. United States,

423 U.S. 212 (1976) ................................................................................................ 11

City of N.Y. v. Arm or Ally LLC, et al.,

22-CV-5525, ECF No. 9 (S.D.N.Y. June 29, 2022) ................................................ 20

City of Syracuse, et al. v. ATF,

1:20-CV-6885, ECF No. 64-34 (S.D.N.Y. Dec. 9, 2020)................................... 20, 21

District of Columbia v. Heller,

554 U.S. 570 (2008) ................................................................................................ 11

District of Columbia v. Polymer80, Inc.,

No. 2020-CA-002878-B (D.C. Sup. Ct. Aug. 10, 2022) .......................................... 17

Div. 80, LLC v. Garland, No. 3:22-CV-148, 2022 WL 3648454, at *3–5 

(S.D. Tex. Aug. 23, 2022) ....................................................................................... 22

Huddleston v. United States,

415 U.S. 814 (1974) ............................................................................................ 9, 10

Local Union No. 38, Sheet Metal Workers’ Int’l Ass’n v. Pelella,

350 F.3d 73 (2d Cir. 2003)........................................................................................ 7

Morehouse Enterprises LLC v. Merrick Garland, et al.,

No. 3:22-CV-00116-PDW-ARS, ECF No. 85 (D.N.D. Aug. 23, 2022).............passim

Nat’l Shooting Sports Found., Inc. v. Jones,

716 F.3d 200 (D.C. Cir. 2013) .......................................................................... 14, 15

New York v. Burger, 482 U.S. 691, 713 (1987) ............................................................ 8

N.Y. State Rifle & Pistol Assoc., Inc. v. Bruen,

142 S. Ct. 2111 (2022) ............................................................................................ 11

People v. Blackhawk Mfg. Grp., et al.,

CGC-21-594577 (Cal. Super. Ct. Aug. 18, 2021)................................................... 20

Shawano Gun & Loan, LLC v. Hughes,

650 F.3d 1070 (7th Cir. 2011) ................................................................................ 13

United States v. Annis,

446 F.3d 852 (8th Cir. 2006) .................................................................................. 17

Case 4:22-cv-00691-O Document 59 Filed 09/08/22 Page 3 of 31 PageID 770
iii

United States v. Cooper,

714 F.3d 873 (5th Cir. 2013) .................................................................................. 16

United States v. Fuller-Ragland,

931 F.3d 456 (6th Cir. 2019) .................................................................................. 15

United States v. Hardin,

889 F.3d 945 (8th Cir. 2018) .................................................................................. 16

United States v. Harris,

720 F.3d 499 (4th Cir. 2013) .................................................................................. 14

United States v. Marzzarella,

614 F.3d 85 (3d Cir. 2010)................................................................................ 14, 15

United States v. Mobley,

956 F.2d 450 (3d Cir. 1992).................................................................................... 15

United States v. Mullins,

446 F.3d 750 (8th Cir. 2006) .................................................................................. 17

United States v. Rivera,

415 F.3d 284 (2d Cir. 2005).................................................................................... 16

United States v. Smith,

477 F.2d 399 (8th Cir. 1973) .................................................................................. 17

United States v. St. Hilaire,

960 F.3d 61 (2d Cir. 2020)...................................................................................... 15

West Virginia v. EPA,

142 S. Ct. 2587 (2022) ............................................................................................ 22

Statutes and Regulations

18 U.S.C.

§§ 921–931 ................................................................................................................ 2

§ 921(a)(3) ........................................................................................................passim

§ 922........................................................................................................................ 10

§ 922(a)(1)(A) ............................................................................................................ 9

§ 922(a)(6) ......................................................................................................... 11, 13

§ 922(b)...................................................................................................................... 9

§ 922(d)...................................................................................................................... 9

§ 922(g)(1)(A) .......................................................................................................... 15

§ 922(k) ................................................................................................................... 14

§ 922(t) .................................................................................................................... 11

§ 922(t)(1)................................................................................................................ 10

§ 923(i) .................................................................................................................... 14

Case 4:22-cv-00691-O Document 59 Filed 09/08/22 Page 4 of 31 PageID 771
iv

§ 923(g)(1)(B) .......................................................................................................... 15

§ 923(g)(3) ............................................................................................................... 10

§ 924........................................................................................................................ 10

87 Fed. Reg.

24652

24676......................................................................................................................... 4

Clean Air Act................................................................................................................ 22

Gun Control Act of 1968, Pub. L. No. 90-618, 82 Stat. 1213 ..............................passim

U.S.S.G. § 2K2.1(b)(4)(B)............................................................................................. 14

Other Authorities

27 C.F.R.

§ 478.73................................................................................................................... 10

§ 478.92................................................................................................................... 14

§ 478.99..................................................................................................................... 9

§§ 478.101 ................................................................................................................. 9

§ 478.102(a)............................................................................................................. 10

§§ 478.121–134 ................................................................................................. 10, 15

§ 478.121(b)............................................................................................................. 15

80% Lower Guide, Tactical Machining (last visited Aug. 26, 2022), 

https://bit.ly/3pTHfAC...................................................................................... 16, 23

About, R&B Tactical Tooling (last visited Aug. 28, 2022), 

https://bit.ly/3oNKmZU.......................................................................................... 12

Are Felons Restricted from Owning a Firearm that Was Built from an 

80% Receiver?, Polymer80 Blog (Oct. 21, 2020), formerly at 

https://bit.ly/3DDzXGo ........................................................................................... 12

Definition of “Frame or Receiver” and Identification of Firearms, 87 

Fed. Reg. 24652, 24656 (Apr. 26, 2022)..........................................................passim

Ghost Gunner, Ghost Guns (last visited Aug. 28, 2022),

https://bit.ly/3pUjDvj.............................................................................................. 12

Ghost Guns Recoveries and Shootings, Everytown Research (Apr. 8, 

2022), https://bit.ly/3bSCcwt.................................................................................... 3

Glenn Thrush, ‘Ghost Guns’: Firearm Kits Bought Online Fuel 

Epidemic of Violence, N.Y. Times (Nov. 14, 2021) ................................................ 19

GST-9: 80% Pistol Build Kit, 80% Arms (last visited Aug. 28, 2022), 

https://bit.ly/3x6n0T7 ............................................................................................. 19

Case 4:22-cv-00691-O Document 59 Filed 09/08/22 Page 5 of 31 PageID 772
v

Gun: Enforcing Federal Laws Against Firearms Traffickers, U.S. Dept. 

of the Treasury at 10 (June 2000), https://bit.ly/3JXi6OP.................................... 13

Gun Violence Archive (July 18, 2022), https://bit.ly/3vXsrVa ..................................... 3

H. Rep. No. 90-1577 (1968)............................................................................................ 8

H. Rep. No. 116-88 (2019)...................................................................................... 15, 16

The History of Legally Buying Firearms Without an FFL, 80% Arms 

Blog (Dec. 3, 2019), https://bit.ly/3HClkFU........................................................... 12

How-To Manuals (last visited Aug. 28, 2022), https://bit.ly/3qUwobt ...................... 19

Jonathan Edwards, A 13-Year-Old Boy Made and Trafficked ‘Ghost 

Guns,’ Authorities Say, and Then Killed His Sister with One, Wash. 

Post. (Dec. 3, 2021)................................................................................................. 18

JSD, Premier Gun Parts and Accessories, JSD Supply (last visited Aug. 

28, 2022), formerly at https://bit.ly/3rKrgqj and archived at

https://bit.ly/3pPlUZ5............................................................................................. 12

Kallie Cox, Once a Week, Police Find These Homemade Guns. Federal 

Law Just Got Tougher, Charlotte Observer (Aug. 25, 2022), https://

www.charlotteobserver.com/news/local/crime/article264856744.html ................ 18

Kathy Reakes, 4 Charged, 31 Ghost Guns Seized in Multi-Agency 

Yonkers Bust, Yonkers Daily Voice (Aug. 9, 2022), 

https://bit.ly/3C757bc ............................................................................................... 3

Lower Receiver, SS-Arms (last visited Aug. 28, 2022),

https://bit.ly/3GAVvVo ........................................................................................... 12

S. Rep. No. 89-1866 (1966) .......................................................................................... 12

S. Rep. No. 90-1501 (1968) ............................................................................................ 8

T. Hart, In the Matter of the Search of the Business and Federal 

Firearms Licensee Known as Polymer80 (D. Nev. Dec, 9, 2020), 

https://on.wsj.com/3pivOCi..................................................................................... 23

Trafficking & Straw Purchasing, Giffords Law Center (last visited 

Aug. 28, 2022), https://bit.ly/3FBTtnv................................................................... 13

Untraceable: The Rising Specter of Ghost Guns, Everytown Research

(May 14, 2020), https://bit.ly/3DTrIWj .................................................................. 18

Webster’s Third New International Dictionary 1889 (1965) ...................................... 22

Case 4:22-cv-00691-O Document 59 Filed 09/08/22 Page 6 of 31 PageID 773
1

DISCLOSURE STATEMENT

Amici curiae submit that Brady United Against Gun Violence (“Brady”), 

Everytown for Gun Safety Action Fund (“Everytown”), and March For Our Lives 

(“MFOL”) (collectively, the “Gun Violence Prevention Groups”) are nonprofit 

corporations with no parent corporations. No publicly held company owns 10% or 

more of the stock of Brady, Everytown, or MFOL.

STATEMENT OF INTEREST

The Gun Violence Prevention Groups submit this amicus brief in support of 

Defendants’ opposition to Plaintiffs’ motion for a preliminary injunction.

Brady is the nation’s longest-standing nonpartisan, nonprofit organization 

dedicated to reducing gun violence through education, research, and advocacy. Brady 

has researched the prevalence of ghost guns, created resources to demonstrate the 

ease with which ghost guns can be obtained and assembled, and advocated on behalf 

of commonsense measures to stop the spread of ghost guns. 

Everytown is the nation’s largest gun-violence-prevention organization. 

Everytown has advocated on behalf of measures to limit the proliferation of 

unserialized firearms and extensively studied the detrimental effects of these 

firearms on safety and federal and state laws. 

MFOL is a nationwide organization of young people who support sensible gunviolence-prevention policies. MFOL has fought to curtail the rapid rise of ghost guns 

and has focused on the deadly effects of ghost guns on teenagers.

Case 4:22-cv-00691-O Document 59 Filed 09/08/22 Page 7 of 31 PageID 774
2

INTRODUCTION

To advance public safety and aid law enforcement, the Gun Control Act of 1968 

(“Act”), Pub. L. No. 90-618, 82 Stat. 1213, as amended, subjects “firearms” to key 

requirements: background checks to prevent sales to persons who have committed 

felonies, who are fugitives, and who are minors, among others; licensing for 

manufacturers, importers, and dealers to ensure that firearms are built and sold 

responsibly; and serialization to trace guns to their first retail sale. 18 U.S.C. §§ 921–

931. Congress intended these requirements to “prevent guns from falling into the 

wrong hands” and to “assist law enforcement . . . in investigating serious crimes.” 

Abramski v. United States, 573 U.S. 169, 172, 180 (2014). 

The recent and rapid proliferation of “ghost guns” has undermined the Act and 

Congress’s law-and-order objectives. A ghost gun is a fully functional, unserialized, 

and untraceable weapon that can be assembled in an hour or less from partially 

complete frames and receivers that are freely available online or at gun shows 

(including as part of ghost gun “kits”) with no background check and no questions 

asked. Ghost guns thwart the Act by allowing criminals and other prohibited 

individuals to acquire, use, and traffic weapons, all while remaining undetectable to 

law enforcement.

In recent years, recoveries of ghost guns in connection with crimes have 

increased at an alarming rate. Law enforcement reported 19,344 recoveries of ghost 

guns in 2021, compared to 1,758 recoveries in 2016; 692 ghost guns were recovered 

Case 4:22-cv-00691-O Document 59 Filed 09/08/22 Page 8 of 31 PageID 775
3

in connection with a homicide or attempted homicide.1 The threat posed by ghost 

guns shows no signs of abating on its own. In July 2022, a 17-year-old shot herself in 

the face with a ghost gun built by her cousin—even though the family was prohibited 

from having guns due to the victim’s mother’s felony conviction.2 The month before, 

four individuals were charged with trafficking 31 ghost guns across state lines.3

ATF acted prudently and well within its authority in promulgating Definition 

of “Frame or Receiver” and Identification of Firearms, 87 Fed. Reg. 24652 (Apr. 26, 

2022) (the “Rule”). See Morehouse Enters. v. Bureau of Alcohol, Tobacco, Firearms 

and Explosives, No. 3:22-CV-116, 2022 WL 3597299, at *5 (D.N.D. Aug. 23, 2022)

(D.N.D. Aug. 23, 2022) (Morehouse Enterprises) (“[T]he [] Rule falls well-within the 

ATF’s agency rulemaking authority as delegated by Congress.”). The Act defines 

“firearm” to include not only fully complete firearms, but also “frame[s]” or 

“receiver[s]” that are “designed to” be or that “may readily be converted” into operable 

weapons. 18 U.S.C. § 921(a)(3). That unambiguously encompasses ghost gun kits 

and the partially complete frames and receivers they contain, which are designed to 

be and readily can be converted into operable and unserialized weapons in an hour 

or less. Indeed, that is their only purpose. With this in mind, the Rule confirms that 

1 Definition of “Frame or Receiver” and Identification of Firearms, 87 Fed. Reg. 24652, 

24656 (Apr. 26, 2022).

2 Gun Violence Archive (July 18, 2022), https://bit.ly/3vXsrVa.

3 Kathy Reakes, 4 Charged, 31 Ghost Guns Seized in Multi-Agency Yonkers Bust, 

Yonkers Daily Voice (Aug. 9, 2022), https://bit.ly/3C757bc; see also, e.g., Ghost Guns 

Recoveries and Shootings, Everytown Research (Apr. 8, 2022), https://bit.ly/3bSCcwt.

Case 4:22-cv-00691-O Document 59 Filed 09/08/22 Page 9 of 31 PageID 776
4

the core building blocks of ghost guns—unserialized, partially complete frames (the 

core component of pistols), partially complete receivers (the core component of long 

guns), and the kits enabling quick and easy conversion of these frames and receivers 

into operable weapons—are “firearms” under the plain language of the Act. Amici 

underscore three of the many reasons why the Rule is sound and should be upheld. 

First, the Rule faithfully implements the Act’s language and prevents the 

subversion of its law-and-order purpose. The Act provides that “firearms” may be 

sold commercially only by licensed dealers and to law-abiding and responsible persons 

who pass a background check. Ghost gun kits and partially complete frames and 

receivers are “designed to” be and “may readily be converted” into operable weapons, 

and thus are, by definition, firearms. 18 U.S.C. § 921(a)(3). Were they not regulated 

as such, they could continue to be sold by anyone and to anyone—the opposite of what 

Congress intended. Indeed, “Plaintiffs’ position would appear to contradict the plain 

language of the [Act], which clearly defined ‘firearms’ more broadly than a fully 

operational weapon.” Morehouse Enterprises, at *6. The Act also requires commercial 

firearms to possess a serial number and criminalizes obliterating that number—all 

in order to help law enforcement fight crime. Ghost gun kits and partially complete 

frames and receivers lack serial numbers and, as such, are largely invisible to law 

enforcement.4

4 References to background checks and serialization are limited to firearms that are 

distributed commercially, as the Rule does not require background checks on private 

firearm sales or restrict persons not otherwise prohibited from possessing firearms 

from making unserialized firearms for personal use. 87 Fed. Reg. 24652, 24676. 

Case 4:22-cv-00691-O Document 59 Filed 09/08/22 Page 10 of 31 PageID 777
5

Second, beyond remaining faithful to the Act’s language, the Rule recognizes 

practical reality in accounting for the ease and speed with which ghost gun kits and 

partially complete frames and receivers can and are intended to be completed into 

deadly weapons. As ghost gun companies’ advertising and marketing materials make 

clear, ghost gun kits and partially complete frames and receivers are designed with 

the sole purpose of being converted into fully functioning weapons. True to that 

purpose, such kits and partially complete frames and receivers enable sophisticated 

and novice purchasers alike to convert these items into operable weapons swiftly and 

easily. Plaintiffs concede as much by acknowledging that the Rule regulates “selfmanufacturing weapons at home” via ghost gun kits and partially complete frames 

and receivers. ECF No. 16, at 4.

Third, the Rule continues ATF’s longstanding view that partially complete 

frames and receivers can be “firearms.” Shortly after the Act’s passage, ATF 

recognized that partially complete frames or receivers that could readily be converted 

into operable weapons were indeed “firearms,” judging by the ease and speed with 

which they could be rendered functional. That the ghost gun industry has flouted 

ATF’s oversight by hiding the ease and speed with which ghost guns can be assembled 

confirms that the industry knows what the Act has said all along: partially complete 

frames and receivers “designed” to be or that may “readily be” converted into weapons 

are “firearms.” Plaintiffs’ contention that the Rule attempts to “rewrite federal law,” 

ECF No. 16, at 1, and would “completely alter the entire landscape of firearm 

Case 4:22-cv-00691-O Document 59 Filed 09/08/22 Page 11 of 31 PageID 778
6

regulation in the United States,” ECF No. 16, at 12, is thus ahistorical and belied by 

the industry’s own behavior.5 

ARGUMENT

I. THE RULE FAITHFULLY IMPLEMENTS THE GUN CONTROL ACT 

AND PREVENTS ITS SUBVERSION

A. The Rule Implements the Act’s Clear Definition of “Firearm.”

The Gun Control Act defines “firearm” as follows:

(A) any weapon (including a starter gun) which will or is designed to or 

may readily be converted to expel a projectile by the action of an 

explosive; (B) the frame or receiver of any such weapon; (C) any firearm 

muffler or firearm silencer; or (D) any destructive device.

18 U.S.C. § 921(a)(3) (emphases added). 

Taken together, (A) and (B) classify as “firearms” partially complete frames 

and receivers and ghost gun kits that are “designed to” be or may “readily be 

converted” into operable weapons. That is because “firearm” is defined as the “frame 

or receiver of any such weapon,” with “such weapon” in (B) referring back to “weapon” 

in (A), which in turn encompasses “any weapon” that is “designed to or may readily 

be converted to expel a projectile by the action of an explosive.” In other words, when 

(B) refers to “the frame or receiver of any such weapon,” it incorporates the 

description of “weapon” in (A), which covers components presently configured to fire 

and components that are “designed to [be] or may readily be converted” into operable 

weapons. See Morehouse Enterprises, at *6 (“the plain language of the [Act], [] clearly 

5 See Morehouse Enterprises, at *11 (That the Rule “regulat[es] a non-operational kit 

that can be readily turned into an operational firearm is not a significant [policy] 

change” since “a non-operational weapon which can be made operational already 

qualifies as a firearm under 18 U.S.C. § 921(a)(3)(A).”).

Case 4:22-cv-00691-O Document 59 Filed 09/08/22 Page 12 of 31 PageID 779
7

defined ‘firearms’ more broadly than a fully operational weapon.”); cf. Local Union 

No. 38, Sheet Metal Workers’ Int’l Ass’n v. Pelella, 350 F.3d 73, 81 (2d Cir. 2003) (“any 

such action” “refers back to” the phrase providing a right to “institute an action”) 

(citation omitted). Because (A) includes not-yet-operable and not-yet-finished 

weapons, it follows that the “frame or receiver of any such weapon” in (B) includes 

partially complete frames or receivers as well (so long as they are “designed to” be or 

may “readily be converted” into the frame or receiver of an operable firearm).6 

Tellingly, Plaintiffs do not try to reconcile the phrase “such weapon” with their 

reading. ECF No. 16, at 8. 

Under a straightforward application of that definition, partially complete 

frames and receivers, and the ghost gun kits used to assemble such frames and 

receivers into operable weapons, are “firearms” whenever they are “designed to” be 

or may “readily be converted” into operable weapons. See Morehouse Enterprises, at 

*5 (The Rule’s “language . . . as well as the [ghost gun] kits at issue . . . fit squarely 

within the [Act’s] “firearm” definition because after delivery, the kits are easily 

converted from mere parts into a weapon that expels a projectile.”). 

Notably, despite Plaintiffs’ euphemism that ghost gun kits and partially 

complete frames and receivers are mere “items” untethered to operational firearms, 

6 Plaintiffs implicitly concede that at least some partially complete frames and 

receivers can qualify as firearms. That is because Plaintiffs endorse the so-called 

“80% rule,” ECF No. 16, at 16, 19, 30, which posits that a frame or receiver that is 

“80%” complete has not yet reached a stage of manufacture to be a “firearm.” This 

rule—although divorced from the Act’s text—posits that a partially complete frame 

or receiver can at some point qualify as a firearm (e.g., an “85% complete” frame).

Case 4:22-cv-00691-O Document 59 Filed 09/08/22 Page 13 of 31 PageID 780
8

ECF No. 16, at 16–17, 19–20, 25, 27, they remarkably fail to identify even a single

alternative use for ghost gun kits and partially complete frames and receivers other 

than constructive unserialized, fully operational weapons. And they cannot: the 

exclusive purpose for which these frames, receivers, and kits are made, marketed, 

and sold, is conversion into operable weapons without difficulty or expertise. Failing 

to regulate these items as “firearms” would ignore the Act’s plain language. 

B. The Rule Advances the Act’s Purpose.

The Act’s purpose demands the same interpretation. The Act has two principal 

ends and two principal means, all which are directly served by the Rule’s approach. 

Through the Act, Congress sought to: (1) promote public safety by “keep[ing] firearms 

out of the hands of those not legally entitled to possess them,” such as persons who 

have committed felonies, have been convicted of domestic abuse, or are otherwise 

dangerous, and (2) “assist law enforcement . . . in combating . . . crime.” S. Rep. No. 

90-1501, at 22 (1968) (“Senate Report”); H. Rep. No. 90-1577, at 4412 (1968) 

(underscoring the “need” to combat “the growing use of firearms in violent crime”).7 

Because unregulated ghost gun kits and partially complete frames and 

receivers allow dangerous and prohibited individuals to obtain deadly and 

untraceable firearms, failing to regulate these items as “firearms” undermines the 

Act’s ends. Congress’s chosen means were as follows: (1) regulating who may buy or 

7 See New York v. Burger, 482 U.S. 691, 713 (1987) (The Act achieves its “regulatory 

goals” of “prevent[ing firearm] sales to undesirable customers and [] detect[ing] the 

origin of particular firearms” in support of law enforcement by “ensur[ing] that 

‘weapons [are] distributed through regular channels and in a traceable manner.’”

(quoting United States v. Biswell, 406 U.S. 311, 315-16 (1972)).

Case 4:22-cv-00691-O Document 59 Filed 09/08/22 Page 14 of 31 PageID 781
9

sell firearms; and (2) imposing strict rules on how firearms and firearm transactions 

are documented and tracked. Infra. Because the Act’s tight limits on purchase, sale, 

and distribution apply to frames and receivers designed to be or readily convertible 

into operable weapons, the Rule’s coverage of ghost gun kits and partially complete 

frames and receivers is faithful to the means enshrined in the Act’s language. Indeed, 

as detailed infra, failing to regulate these items as what they are—firearms—would 

undermine both the Act and other safety regulations that cross-reference or otherwise 

rely upon the Act’s definition of “firearm.”

Federal firearms licensees. The Act designates federal firearms licensees 

(“FFLs”)—those who manufacture, sell, or import firearms—the “principal agent of 

[law] enforcement” in “restricting . . . access to firearms.” Huddleston v. United 

States, 415 U.S. 814, 824 (1974). If ghost gun kits and partially complete frames and 

receivers were not treated as firearms (as the Act requires), the effect would be to 

continue to sideline FFLs with respect to the sale and acquisition of a rapidly growing 

source of crime guns across the country. 

Under the Act, FFLs—and only FFLs—may “engage in the business of 

importing, manufacturing, or dealing in firearms.” 18 U.S.C. § 922(a)(1)(A); see id. 

§ 923(a). In exchange for this right to engage in the firearms business, FFLs must 

serve as the Act’s frontline mechanism for implementation:

• FFLs may not “sell or deliver” firearms to individuals who, inter alia, 

are underage, reside out-of-state (with limited exceptions), or have a 

criminal history. 18 U.S.C. §§ 922(b), 922(d); see 27 C.F.R. § 478.99. 

• FFLs must keep extensive inventory and transaction records and must 

report suspicious purchasing patterns. 27 C.F.R. §§ 478.101 (recordCase 4:22-cv-00691-O Document 59 Filed 09/08/22 Page 15 of 31 PageID 782
10

keeping), 478.121–134 (same); 18 U.S.C. § 923(g)(3) (FFLs must report 

when an individual buys multiple guns within a short timeframe).

• FFLs must make their records accessible to law enforcement officials, 

who can and often do access these records to monitor, prevent, 

investigate, and combat firearm-related crimes. See infra.

FFLs that fail to meet these or other duties may lose their license, 27 C.F.R. § 478.73, 

and may be held accountable through both civil and criminal liability, 18 U.S.C. 

§§ 922, 924.

The Act and its implementing regulations thus enshrine FFLs as scrutinizing 

gatekeepers at the point of sale, subject to harsh penalties for noncompliance.8 But 

FFLs’ functions and enforcement mechanisms attach only to “firearms.” If ghost gun 

kits and partially complete frames and receivers are not treated as “firearms,” FFLs 

would continue to be displaced as the “principal agent of [law] enforcement” for this 

rapidly expanding source of crime guns. Huddleston, 415 U.S. at 824. 

Background checks. The Act requires every individual who purchases a 

firearm from an FFL to submit to a background check. 18 U.S.C. § 922(t)(1); 27 C.F.R. 

§ 478.102(a). Absent recognizing ghost gun kits and unfinished frames and receivers 

as firearms—as the Act requires and the Rule confirms—untraceable and functional 

firearms could be acquired by anyone, regardless of background: criminals, domestic 

abusers, minors, and persons with severe mental illness, to name a few.

8 In monitoring the point of sale, the Act proactively keeps firearms out of dangerous 

hands, rather than forcing law enforcement to restrict possession after the firearms 

have entered circulation. The Rule furthers this prophylactic premise: public safety 

is better served by preventing a violent criminal from purchasing a gun than it is by 

recovering a gun after a crime has already occurred.

Case 4:22-cv-00691-O Document 59 Filed 09/08/22 Page 16 of 31 PageID 783
11

Allowing unfettered access to dangerous weapons is the opposite of what 

Congress envisioned. In tightly regulating who may purchase a firearm under the 

Act, “Congress . . . sought broadly to keep firearms away from the persons Congress 

classified as potentially irresponsible and dangerous.” Barrett v. United States, 423 

U.S. 212, 218 (1976). That approach is consistent with a “longstanding” historical 

tradition of “prohibitions on the possession of firearms” that further public order, such 

as limiting possession by “felons and the mentally ill.” District of Columbia v. Heller, 

554 U.S. 570, 626–27 (2008); see N.Y. State Rifle & Pistol Assoc., Inc. v. Bruen, 142 S.

Ct. 2111, 2122, 2133–34 (2022) (the Constitution protects “the right of an ordinary, 

law-abiding citizen . . . .”) (emphasis added). The Act continues that tradition by 

“establish[ing] a detailed scheme to enable the dealer to verify . . . whether a potential 

buyer may lawfully own a gun.” Abramski, 573 U.S. at 172. 

So important is the purchaser’s law-abiding status that it is a crime for an FFL 

to sell a firearm without running a background check on the transferee, 18 U.S.C. 

§ 922(t); for a buyer to “make any false or fictitious oral or written statement” 

concerning their identity, id. § 922(a)(6); and for FFLs to make any “false” statement 

in records relating to a buyer’s identity, id. §§ 922(m), 924(a)(3). The Rule faithfully 

implements Congress’s calibration of who may possess a firearm and the scheme for 

preventing circumvention of those rules. Plaintiffs’ position would breathe life into 

the exact dangers the Act was designed to address. Congress saw “the ease with 

which any person can anonymously acquire firearms” as “a matter of serious national 

concern,” and responded accordingly. Senate Report at 22. For instance, to curtail 

Case 4:22-cv-00691-O Document 59 Filed 09/08/22 Page 17 of 31 PageID 784
12

anonymous purchases, Congress barred “the commercial mail-order traffic in 

firearms to unlicensed persons.” Id. at 23. In fact, Congress rejected earlier proposed 

legislation because such legislation failed to “prohibit the mail-order sale” of firearms 

known for “their susceptibility to crimes.” S. Rep. No. 89-1866, at 34, 100 (1966). 

Absent regulation as firearms, ghost gun kits and partially complete frames 

and receivers are the modern incarnation of mail-order guns: they allow anonymous 

buyers (including criminals) to purchase a firearm remotely and have that firearm 

shipped across state lines to facilitate crime. In recent years, this has occurred 

regularly, nationwide. And ghost gun kit manufacturers, for their part, have 

advertised anonymity and the avoidance of background checks as reasons to purchase 

their wares.9 

Straw purchases. Failing to classify ghost gun kits and partially complete 

frames and receivers as firearms would dilute the Act’s ban on “straw purchases,” i.e., 

gun purchases made by someone who can pass a background check on behalf of 

someone else—often a prohibited buyer. Purchasers of ghost gun kits or partially 

9 See, e.g., Are Felons Restricted from Owning a Firearm that Was Built from an 80% 

Receiver?, Polymer80 Blog (Oct. 21, 2020), formerly at https://bit.ly/3DDzXGo 

(“Convicted felons are not restricted from purchasing and owning 80% frames . . . .”); 

The History of Legally Buying Firearms Without an FFL, 80% Arms Blog (Dec. 3, 

2019), https://bit.ly/3HClkFU (no background check or serial number required); Ghost 

Gunner, Ghost Guns (last visited Aug. 28, 2022), https://bit.ly/3pUjDvj (same); Lower 

Receiver, SS-Arms (last visited Aug. 28, 2022), https://bit.ly/3GAVvVo (same); About, 

R&B Tactical Tooling (last visited Aug. 28, 2022), https://bit.ly/3oNKmZU (same); 

JSD, Premier Gun Parts and Accessories, JSD Supply (last visited Aug. 28, 2022), 

formerly at https://bit.ly/3rKrgqj and archived at https://bit.ly/3pPlUZ5 (same). The 

JSD Supply website removed that language around the time the Rule took effect.

Case 4:22-cv-00691-O Document 59 Filed 09/08/22 Page 18 of 31 PageID 785
13

complete frames and receivers would not even need to cloak their identities with 

straw purchases if these items were not recognized as firearms.

The Act aims to prevent the diversion of firearms to the black market through 

several means, including by prohibiting “straw purchases.” Straw purchases have 

long fueled illegal gun trafficking. Following the Gun: Enforcing Federal Laws 

Against Firearms Traffickers, U.S. Dept. of the Treasury at 10 (June 2000), 

https://bit.ly/3JXi6OP (“Nearly 50 percent of the ATF investigations involved 

firearms being trafficked by straw purchasers.”); Trafficking & Straw Purchasing, 

Giffords Law Center (last visited Aug. 28, 2022), https://bit.ly/3FBTtnv (noting 

“30,000 attempted straw purchases each year”).

Through several interlocking requirements, the Act forbids straw purchases. 

Gun buyers must fill out “Form 4473,” attesting to their identity as the “actual 

transferee/buyer,” ATF Form 4473 (5300.9), https://bit.ly/3CAv5Rl, and it is a crime 

to misrepresent—on Form 4473 or elsewhere—“any fact material to the lawfulness of 

the sale,” 18 U.S.C. § 922(a)(6); see Abramski, 573 U.S. at 171. Further, any FFL that 

does not take steps to stop straw purchases at the point of sale can lose its license 

and face both civil and criminal liability. See, e.g., Shawano Gun & Loan, LLC v. 

Hughes, 650 F.3d 1070, 1077–79 (7th Cir. 2011). 

As the Supreme Court has recognized, protections against straw purchases are 

essential because, “[p]utting true numbskulls to one side, anyone purchasing a gun 

for criminal purposes would avoid leaving a paper trail by the simple expedient of 

hiring a straw.” Abramski, 573 U.S. at 183. Yet if ghost gun kits and partially 

Case 4:22-cv-00691-O Document 59 Filed 09/08/22 Page 19 of 31 PageID 786
14

complete frames and receivers were wrongly excluded from the definition of 

“firearms,” then none of the tools that ATF employs to combat straw purchases would 

be available to this rapidly proliferating segment of the market, leaving criminal 

buyers with few roadblocks to obtaining firearms.

Serialization, record-keeping, and public safety. Ghost guns contravene 

the Act’s serialization and record-keeping provisions, making it more difficult for law 

enforcement to fight crime. See, e.g., United States v. Marzzarella, 614 F.3d 85, 98 

(3d Cir. 2010) (“[W]e think it plain that [serialization] serves a law enforcement 

interest.”); United States v. Harris, 720 F.3d 499, 502 (4th Cir. 2013) (same). By their 

very nature, ghost guns—easily assembled from partially complete frames and 

receivers that Plaintiffs would carve out of the Act—are fully operational, unmarked, 

and untraceable firearms, which impede law enforcement’s ability to prevent and 

prosecute violent crime by tracing illegal weapons to their source. See Morehouse 

Enterprises, at *12 (clarifying that the Rule advances “ATF’s interest in law 

enforcement and public safety”).

The Act mandates that every firearm possess a unique serial number and 

makes it a crime to tamper with a serial number or even “receive” a firearm with an 

already-tampered-with serial number. 27 C.F.R. § 478.92; 18 U.S.C. §§ 923(i), 922(k). 

Serialization allows ATF “to link a suspect to a firearm.” Nat’l Shooting Sports 

Found., Inc. v. Jones, 716 F.3d 200, 204 (D.C. Cir. 2013). Possessing a firearm with 

an altered serial number triggers a sentencing enhancement—even if law 

enforcement can reconstruct the number. U.S.S.G. § 2K2.1(b)(4)(B); see United States 

Case 4:22-cv-00691-O Document 59 Filed 09/08/22 Page 20 of 31 PageID 787
15

v. St. Hilaire, 960 F.3d 61, 64 (2d Cir. 2020); United States v. Fuller-Ragland, 931 

F.3d 456, 467 (6th Cir. 2019). 

 The Act also assists law enforcement by subjecting FFLs to record-keeping 

duties to track firearm sales and inventory. 18 U.S.C. § 922(g)(1)(A); 27 C.F.R. 

§§ 478.121–134. Law enforcement may “examine the inventory and records of [FFLs] 

. . . without . . . reasonable cause or warrant,” “in the course of a reasonable inquiry 

during the course of a criminal investigation.” 18 U.S.C. § 923(g)(1)(B); see 27 C.F.R. 

§ 478.121(b). “FFL records” allow law enforcement to “trace a firearm” and identify 

its “path through the distribution chain.” Nat’l Shooting Sports, 716 F.3d at 204 

(cleaned up).

Without serialization and record-keeping, including for ghost gun kits and 

partially complete frames and receivers, these law enforcement mechanisms break 

down. United States v. Mobley, 956 F.2d 450, 454 (3d Cir. 1992) (it is “no secret that 

a chain of custody for a firearm greatly assists in the difficult process of solving 

crimes,” and that, without “serial numbers,” reconstructing that chain is “virtually 

impossible”); Marzzarella, 614 F.3d at 98 (“Firearms without serial numbers are of 

particular value to those engaged in illicit activity.”). Plaintiffs regard the term 

“ghost guns” as “derogatory” and take offense at the suggestion that their ghost guns 

“enabl[e] criminals,” ECF No. 16, at 23, but these protestations are belied by a House 

Committee report, which expressly warned that “[g]host guns” pose a “homeland 

security challenge” because they “hamstring[] law enforcement’s ability to investigate 

crimes,” as such crimes are “committed with untraceable weapons.” H. Rep. No. 116-

Case 4:22-cv-00691-O Document 59 Filed 09/08/22 Page 21 of 31 PageID 788
16

88, at 2 (2019). This conclusion tracks common sense: would-be criminals naturally 

prefer untraceable ghost guns to traceable options.10

II. THE RULE APPROPRIATELY CONSIDERS THE PRACTICAL 

REALITY THAT GHOST GUNS CAN BE QUICKLY AND EASILY 

ASSEMBLED BY NONEXPERTS

The Act defines “firearm” in practical terms, covering not only fully complete 

weapons, but also frames and receivers that are designed to be or may readily be 

converted into operable weapons—thus regulating items that exist for no other 

purpose and almost certainly will become weapons. 18 U.S.C. § 921(a)(3). The Rule 

is faithful to this statutory definition and Congress’s pragmatic approach, recognizing 

that ghost guns can be assembled from ghost gun kits and partially complete frames 

and receivers easily and without any technical expertise, in an hour or less. 

Courts have widely agreed that, under the Act, a “weapon designed to fire a 

projectile” that is “temporarily incapable of effecting its purpose,” is not “removed 

from” the definition of a “firearm.” United States v. Rivera, 415 F.3d 284, 286 (2d Cir. 

2005); see, e.g., United States v. Cooper, 714 F.3d 873, 881 (5th Cir. 2013) (“[W]e have 

consistently held that inoperable firearms can support convictions [under section 

921(a)(3).]”); United States v. Hardin, 889 F.3d 945, 949 (8th Cir. 2018) (rejecting 

argument that the “disrepair” of a gun, which rendered it inoperable, changed that 

10 For example, the website of Plaintiff Tactical Machining, LLC (“Tactical 

Machining”) advertises to prospective purchasers that the company’s “80% lower” 

receivers are “machined as far as you can” to being operable firearms so as to avoid 

“requir[ing them] to be transferred to an FFL” with all its attendant regulations. 80% 

Lower Guide, Tactical Machining (last visited Aug. 26, 2022), https://bit.ly/3pTHfAC

(emphasis added). In practical terms, the sale of such receivers transparently aims 

to skirt the Act’s goal of proper FFL recordkeeping and hamper law enforcement 

efforts to prevent and investigate gun trafficking and violence.

Case 4:22-cv-00691-O Document 59 Filed 09/08/22 Page 22 of 31 PageID 789
17

the gun was “manufactured to be . . . a gun”) (quotation marks omitted). Likewise, 

as the Eighth Circuit has recognized, an object that must be “modified” to function as 

a firearm, is no less a firearm in the eyes of the Act. See United States v. Mullins, 

446 F.3d 750, 756 (8th Cir. 2006) (gun that could be “modified,” “without any 

specialized knowledge, in less than an hour,” is “‘readily convertible’”); United States 

v. Annis, 446 F.3d 852, 857 (8th Cir. 2006) (finding no error in imposing the dangerous 

weapon sentencing enhancement even though the firearm in question “was missing 

both the clip and the bolt” and “partially disassembled”); United States v. Smith, 477 

F.2d 399, 400 (8th Cir. 1973) (gun that required “8-hour working day in a properly 

equipped machine shop” was “readily” convertible into a gun). 

Consistent with this body of precedent, last week, the District Court for the 

District of North Dakota denied a preliminary injunction in another challenge to the 

Rule, concluding that ghost gun kits and partially complete frames and receivers 

constitute firearms because the Act “clearly defined ‘firearms’ more broadly than a 

fully operational weapon” and so “a ‘frame or receiver’ may be considered a firearm 

much sooner in the process than a ‘weapon.’” Morehouse Enterprises, at *6; see id.

(observing that “no provision of federal law foreclos[es] this possibility”). And earlier 

this month, the D.C. Superior Court likewise held that partially complete frames, 

receivers, and kits sold by a ghost gun manufacturer are “firearms” as they may be 

“readily converted.”11 

11 District of Columbia v. Polymer80, Inc., No. 2020-CA-002878-B, at 5 (D.C. Sup. Ct. 

Aug. 10, 2022) (“On Polymer80’s website, they provide instructions to consumers on 

Case 4:22-cv-00691-O Document 59 Filed 09/08/22 Page 23 of 31 PageID 790
18

Not only is the statutory language dispositive, but a mountain of evidence 

confirms that ghost gun kits and partially complete frames and receivers are

designed to be and may readily be converted into operable weapons, and thus are 

“firearms” under the Act. Manufacturers and distributors have advertised that these 

kits, frames, and receivers are designed for the sole purpose of being assembled into 

functional guns. And—consistent with that purpose—these items can in fact be 

easily assembled into functional weapons by the most novice gun-builders, including 

children.12 Specifically, through a single website, one can buy a complete, all-in-one 

kit that “package[s] the unfinished frame or receiver with all the other parts needed 

to complete the firearm.” Untraceable: The Rising Specter of Ghost Guns, Everytown 

Research (May 14, 2020), https://bit.ly/3DTrIWj. Once the kit is delivered, assembly 

is simple. As the head of ATF’s Los Angeles field office observed:

If you can go to one of these big-box stores and put that type of furniture 

together, if you’re putting together your kids Christmas toys, you can 

make a homemade gun. It’s that easy.

Jonathan Edwards, A 13-Year-Old Boy Made and Trafficked ‘Ghost Guns,’ 

Authorities Say, and Then Killed His Sister with One, Wash. Post. (Dec. 3, 2021), 

https://wapo.st/3Ggarb9. 

how to build firearms with these unfinished frames, receivers, and . . . kits.”), 

https://bit.ly/3A1f4EN.

12 See Kallie Cox, Once a Week, Police Find These Homemade Guns. Federal Law Just 

Got Tougher, Charlotte Observer (Aug. 25, 2022), 

https://www.charlotteobserver.com/news/local/crime/article264856744.html (police 

“regularly seize ghost guns and often find youth have them”).

Case 4:22-cv-00691-O Document 59 Filed 09/08/22 Page 24 of 31 PageID 791
19

As Plaintiffs readily admit, these ghost gun kits and partially complete frames 

and receivers readily enable “self-manufacturing weapons at home.” ECF No. 16, at 

4. And, notably, even though Tactical Machining attests to this Court that it does 

not “provide any form of instruction on how to self-manufacture a firearm frame or 

receiver” or include any “tooling” or “jigs” to build operable weapons from partially 

complete frames and receivers, ECF No. 16-1, ¶ 5 (Decl. of Darren Peters, Sr., Owner 

and CEO of Tactical Machining) (emphasis added), its website reveals the opposite. 

Specifically, the company sells ghost gun kits with “Install Instructions,” “the cam 

clamp and takedown pin,” and “[b]oth barrel nut and the alignment tool”—all 

“contained in the assembly.” 80% Build Kits, Tactical Machining (last visited Aug. 

26, 2022), https://bit.ly/3wAHtjZ.

Ghost gun kits are not only designed to be converted into firearms: they are 

designed to be converted quickly. Kit manufacturers and distributors tout this speed 

in marketing materials. See, e.g., GST-9: 80% Pistol Build Kit, 80% Arms (last visited 

Aug. 28, 2022), https://bit.ly/3x6n0T7 (“Our goal was for you to be able to go from 

opening the mail, to a competition or defense ready pistol in under 15 minutes.”). 

Manufacturers and distributors also publish how-to guides to walk novices through 

the fast-and-easy assembly. See, e.g., How-To Manuals, Polymer80 (last visited Aug. 

28, 2022), https://bit.ly/3qUwobt. 

Amateurs and experts alike have assembled kits in around an hour or less. See

Glenn Thrush, ‘Ghost Guns’: Firearm Kits Bought Online Fuel Epidemic of Violence, 

N.Y. Times (Nov. 14, 2021), https://nyti.ms/3EYiedv (“[An] amateur can . . . turn [a 

Case 4:22-cv-00691-O Document 59 Filed 09/08/22 Page 25 of 31 PageID 792
20

kit] into a working firearm in less than an hour.” (emphasis added)); Compl. at ¶¶ 

74, 115, People v. Blackhawk Mfg. Grp., et al., CGC-21-594577 (Cal. Super. Ct. Aug. 

18, 2021) (officer assembled kit in “less than 25 minutes” with tools from a hardware 

store (emphasis added)); id. at ¶ 73 (ATF agent finished kit “in less than nineteen 

minutes” (emphasis added)); Prelim. Inj. Mem., City of N.Y. v. Arm or Ally LLC, et 

al., 22-CV-5525, ECF No. 9, at 11 (S.D.N.Y. June 29, 2022) (ghost gun assembled “in 

approximately an hour and a half”) (emphasis added). In earlier ghost gun 

litigation, one individual who had “never attempted to build a firearm using an 

unfinished frame or receiver,” watched “videos on YouTube for thirty minutes,” then 

built “a complete pistol from [a] handgun kit in 86 minutes.” Decl. of J. McFarlan, 

City of Syracuse, et al. v. ATF, 1:20-CV-6885 (“City of Syracuse”), ECF No. 64-34, at 

¶¶ 8, 10, 11 (S.D.N.Y. Dec. 9, 2020) (emphasis added). The Rule correctly recognizes 

the contemporary reality that anyone with an internet connection, an hour or less of 

free time, and basic household tools can convert ghost gun kits and partially complete 

frames and receivers into operable and untraceable weapons.

III. THE RULE COMPORTS WITH ATF’S LONGSTANDING VIEW THAT 

PARTIALLY COMPLETE FRAMES AND RECEIVERS CAN BE 

FIREARMS 

Plaintiffs erroneously contend that the Rule upends ATF’s historical practice 

and would “dramatically expand” existing ATF regulatory framework. ECF No. 16, 

at 5–9. To the contrary, for years after the Act’s passage, ATF understood that 

Congress defined “firearm” to include some partially complete frames and receivers, 

and that the operative question is how quickly and easily—i.e., how “readily”—a 

frame or receiver can “be converted” into an operable weapon. 18 U.S.C. § 921(a)(3); 

Case 4:22-cv-00691-O Document 59 Filed 09/08/22 Page 26 of 31 PageID 793
21

Morehouse Enterprises, at *11 (regulating “a non-operational kit that can be readily 

turned into an operational firearm is not a significant [policy] change” because “a nonoperational weapon which can be made operational already qualifies as a firearm 

under 18 U.S.C. § 921(a)(3)(A).”). That some purveyors of ghost gun kits and parts 

have tried to affirmatively hide from ATF the ease with which their wares can be 

assembled only reinforces that a partially complete frame or receiver that can quickly 

and easily be converted into a weapon is indeed a “firearm” under the Act. 

The Act was enacted in 1968. In 1976, ATF’s Assistant Chief Counsel issued 

an opinion with a framework for assessing whether a partially complete frame or 

receiver is a “firearm.” Admin. Record, City of Syracuse, ECF No. 60 (S.D.N.Y. Dec. 

8, 2020), at ATF0265. The opinion explained that if “unfinished frames” or “castings” 

“may readily be converted” into weapons, “they are firearms.” Id. at ATF0266 

(emphasis added). The opinion concluded that unfinished frames and receivers must 

be reviewed “case-by-case” to gauge if they are “readily convertible” into weapons:

[W]e view the current Bureau procedure in classifying “firearms” on a 

case-by-case basis as consistent with the letter and spirit of the [] Act. 

It is obvious that what constitutes “readily convertible” depends upon 

the nature of each firearm. That there may be cases where it is difficult 

to determine the side on which a particular “firearm” falls is not a 

sufficient reason to establish a rigid criterion for ... “readily convertible.”

Id. at ATF0267. 

For decades, ATF followed that approach in classification letters that turned 

on whether a partially complete frame or receiver could “readily be converted” into 

an operable weapon. Id. at ATF0001, ATF0014, AATF0020, ATF0023, ATF0050, 

AATF0051, AATF0053, ATF0065. Consistent with the straightforward dictionary 

Case 4:22-cv-00691-O Document 59 Filed 09/08/22 Page 27 of 31 PageID 794
22

definition of “readily”—meaning “without much difficulty” or “with fairly quick 

efficiency”13—several of these letters referenced the ease and speed with which 

partially complete frames and receivers could be assembled into operable weapons. 

Id. at ATF0020 (partially complete receiver was a “firearm” because it required “75 

minutes” of assembly); id. at ATF0024 (partially complete frame was a “firearm” 

because it required “20 minutes” of assembly).14 

Plaintiffs overlook this history altogether, and instead complain that the Rule 

newly regulates “items that may someday become a frame or receiver or even the 

individual parts of a weapon” and “a collection of non-firearm parts (including the 

non-frame or non-receiver).” ECF 16, at 8–9. That complaint is belied by the 

13 Webster’s Third New International Dictionary 1889 (1965) (defining “readily”).

14 This history illustrates one of many ways in which Plaintiffs’ invocation of West 

Virginia v. EPA, 142 S. Ct. 2587 (2022), is misplaced. ECF No. 16, at 21–22 & n.24, 

24. In West Virginia, the Court vacated an EPA rule “claim[ing] to discover” a power 

in the Clean Air Act for the first and only time in four decades. 142 S. Ct. at 2610 

(cleaned up). By contrast, here, the Rule follows a reading of the Act that ATF 

adopted in 1976. Notably, West Virginia’s reliance on the “major questions doctrine” 

also turned on the EPA rule risking “billions” in costs and “tens of thousands of jobs,” 

under an “obscure . . . section of the law.” Id. at 2602, 2604-05. Despite Plaintiffs’ 

alarmist rhetoric that the Rule will cause “[t]he market for privately manufacturing 

firearms” to “likely die,” ECF No. 16, at 37, in reality, the “Rule does not infringe on 

any individuals’ or business’ ability to completely manufacture[] a firearm for 

personal use, nor does it restrict the ability to obtain the weapon kits at issue. . . . [it] 

simply requires serialization of a firearm, when in the stream of commerce, so that it 

may be tracked in the event a crime is committed with the firearm.” Morehouse 

Enterprises, at *8; see Div. 80, LLC v. Garland, No. 3:22-CV-148, 2022 WL 3648454, 

at *3–5 (S.D. Tex. Aug. 23, 2022) (“the only quantified compliance costs” that the Rule 

may impose on ghost gun companies “is a few hundred dollars in licensing fees”). 

Plaintiffs’ contention that operating as FFLs and serializing ghost gun kits and 

partially complete frames and receivers in accordance with the Act “risk the 

destruction of their businesses” rings quite hollow. ECF No. 16, at 38.

Case 4:22-cv-00691-O Document 59 Filed 09/08/22 Page 28 of 31 PageID 795
23

industry’s behavior, including Tactical Machining’s.15 The ghost gun industry has 

seemingly tried to hide from ATF the extent to which ghost gun kits can be “readily” 

converted into deadly weapons—a clear sign that, even before the Rule, the industry 

knew that the Act reaches partially complete frames and receivers. In an affidavit to 

support a warrant to search a facility operated by Polymer80 (the nation’s largest 

public seller of ghost gun kits and parts), an ATF agent stated that, in 2017, 

Polymer80 sought an ATF determination that an unfinished pistol frame is not a 

firearm by misleadingly submitting just the partially complete frame without the rest 

of the kit sold with the frame, which included other parts and tools to complete the 

frame of a ghost gun. Aff. of T. Hart, In the Matter of the Search of the Business and 

Federal Firearms Licensee Known as Polymer80, 3:20-mj-123, ¶¶ 42–43 (D. Nev. Dec, 

9, 2020), https://on.wsj.com/3pivOCi. ATF responded to Polymer80 in a letter noting 

that, “the submitted sample is simply a component of a larger product,” and directing 

Polymer80 to “submit the complete . . . [k]it.” Id. at ¶¶ 43–44. As of December 2020, 

Polymer80 had not “resubmitted the . . . kit.” Id. at ¶ 45. ATF eventually obtained a 

kit through an informant who bought the “Buy Build Shoot” kit—advertised as 

having “all the necessary components” for a gun—with no background check, and 

assembled it into an operable gun in 21 minutes. Id. at ¶ 69. 

In short, ATF has long recognized that partially complete frames and receivers 

that can quickly and easily be assembled into operable weapons are “firearms.” That 

15 See 80% Lower Guide (admitting that Tactical Machining’s 80% receivers are 

intended to bypass federal gun sale regulations by being “machined as far as you can” 

before being classified as operable weapons).

Case 4:22-cv-00691-O Document 59 Filed 09/08/22 Page 29 of 31 PageID 796
24 

the ghost gun industry appears to have hidden the nature of its products from ATF 

only confirms that the industry knows its current practices violate federal law.

CONCLUSION

This Court should deny Plaintiffs’ motion for a preliminary injunction.

August 30, 2022 Respectfully Submitted,

By: /s/ Daniel Grooms

ADAM M. KATZ* 

RACHEL ALPERT* 

COOLEY LLP

500 Boylston Street

Boston, MA 02116

Telephone: (617) 937-2300

akatz@cooley.com 

ralpert@cooley.com 

*pro hac vice pending

DANIEL GROOMS* 

MATT K. NGUYEN* 

COOLEY LLP

1299 Pennsylvania Avenue, NW

Washington, DC 20004

Telephone: (202) 842-7800

dgrooms@cooley.com 

mnguyen@cooley.com 

Counsel for Amici Curiae

Case 4:22-cv-00691-O Document 59 Filed 09/08/22 Page 30 of 31 PageID 797
25 

CERTIFICATE OF SERVICE

I hereby certify that on this 30th day of August 2022, a true and accurate copy 

of the foregoing brief was served via the Court’s CM/ECF system to all counsel of 

record.

August 30, 2022 Respectfully Submitted,

By: /s/ Daniel Grooms 

Case 4:22-cv-00691-O Document 59 Filed 09/08/22 Page 31 of 31 PageID 798