IN THE UNITED STATES DISTRICT COURT

FOR THE NORTHERN DISTRICT OF TEXAS

FORT WORTH DIVISION

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 THE DISTRICT OF COLUMBIA AND THE STATES OF 

NEW JERSEY, PENNSYLVANIA, CALIFORNIA, COLORADO, 

CONNECTICUT, DELAWARE, HAWAII, ILLINOIS, MAINE, 

MARYLAND, MASSACHUSETTS, MICHIGAN, MINNESOTA, NEW 

YORK, NORTH CAROLINA, OREGON, RHODE ISLAND, 

WASHINGTON, AND WISCONSIN AS AMICI CURIAE IN SUPPORT OF 

DEFENDANTS

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TABLE OF CONTENTS

INTRODUCTION AND INTEREST OF AMICI STATES.....................................1

BACKGROUND .......................................................................................................2

SUMMARY OF ARGUMENT.................................................................................5

ARGUMENT.............................................................................................................5

I. The Final Rule Fits Squarely Within The GCA’s 

Comprehensive Scheme, Which Was Designed To Fill Gaps In 

State-By-State Enforcement..................................................................5

II. The Final Rule Complements State Efforts To Regulate 

Unserialized Firearms............................................................................9

A. At least 14 jurisdictions, including the District, have 

passed their own laws regulating kits and other 

unserialized firearms....................................................................9

B. Despite state efforts, the number of unserialized firearms 

has grown exponentially ............................................................12

C. The Final Rule closes the gaps inherent in state-by-state 

enforcement................................................................................15

CONCLUSION........................................................................................................18

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TABLE OF AUTHORITIES

Cases

Abramski v. United States, 573 U.S. 169 (2014)...................................................2, 8

FDA v. Brown & Williamson Tobacco Corp., 529 U.S. 120 (2000).........................7

Moore v. State, 983 A.2d 583 (Md. Ct. Spec. App. 2009) ......................................16

Torres v. Lynch, 578 U.S. 452 (2016) .......................................................................9

United Auto., Aircraft & Agric. Implement Workers of Am. v. Wis. Emp.

Rels. Bd., 351 U.S. 266 (1956) .............................................................................1

United States v. Cruikshank, 92 U.S. 542 (1875)....................................................17

Federal Statutes

18 U.S.C. § 921................................................................................................. 2, 3, 5

18 U.S.C. § 922........................................................................................... 2, 7, 8, 14

18 U.S.C. § 923....................................................................................................2, 16

Regulations

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

87 Fed. Reg. 24652 (Apr. 26, 2022)........................................ 1, 3, 4, 5, 9, 12, 16

Legislative History

H.R. Rep. No. 90-1577 (1968).................................................................... 6, 7, 8, 16

114 Cong. Rec. 13647 (1968)....................................................................................8

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State Statutes 

Ala. Code § 13A-11-64..............................................................................................9

Cal. Penal Code § 16519................................................................................... 10, 16

Cal. Penal Code § 16531..........................................................................................10

Cal. Penal Code § 29180..........................................................................................11

Cal. Penal Code § 29182..........................................................................................11

Cal. Penal Code § 30400................................................................................... 10, 11

Conn. Gen. Stat. Ann. § 29-36a........................................................................ 10, 11

Conn. Gen. Stat. Ann. § 53-206j..............................................................................10

D.C. Code § 7-2501.01 ..............................................................................................9

D.C. Code § 7-2504.08 ............................................................................................11

D.C. Code § 7-2505.01 ............................................................................................11

D.C. Code § 7-2505.02 ............................................................................................11

D.C. Code § 22-4503 ...............................................................................................15

D.C. Code § 22-4514 ...............................................................................................10

Del. Code Ann. tit. 11, § 1448 .................................................................................15

Del. Code Ann. tit. 11, § 1448A ..............................................................................11

Del. Code Ann. tit. 11, § 1448B ..............................................................................11

Del. Code Ann. tit. 11, § 1459A ....................................................................... 10, 11

Haw. Rev. Stat. Ann. § 134-10.2 ...................................................................... 10, 11

720 Ill. Comp. Stat. Ann. 5/24-5.1.................................................................... 10, 11

Ind. Code § 35-47-2-18..............................................................................................9

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Md. Code Ann., Pub. Safety § 5-703................................................................ 10, 11

Mass. Gen. Laws ch. 269, § 11E..............................................................................11

Minn. Stat. Ann. § 609.667......................................................................................10

Mont. Code Ann. § 45-6-326.....................................................................................9

Neb. Rev. Stat. § 28-1207..........................................................................................9

N.J. Stat. Ann. § 2C:39-9.................................................................................. 10, 11

N.J. Stat. Ann. § 2C:58-2.........................................................................................11

N.J. Stat. Ann. § 2C:58-3.........................................................................................15

N.Y. Penal Law § 265.01.........................................................................................10

N.Y. Penal Law § 265.07.........................................................................................11

N.Y. Penal Law § 265.60.........................................................................................11

N.Y. Penal Law § 265.61.........................................................................................11

N.Y. Penal Law § 265.63.........................................................................................11

N.Y. Penal Law § 265.64.........................................................................................11

Nev. Rev. Stat. Ann. § 202.360 ...............................................................................15

Nev. Rev. Stat. Ann. § 202.3625 .............................................................................11

Nev. Rev. Stat. Ann. § 202.363 ...............................................................................10

Nev. Rev. Stat. Ann. § 202.3635 .............................................................................10

R.I. Gen. Laws Ann. § 11-47-2................................................................................10

R.I. Gen. Laws Ann. § 11-47-8......................................................................... 10, 11

R.I. Gen. Laws Ann. § 11-47-40..............................................................................11

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S.D. Codified Laws § 22-14-5 ...................................................................................9

Tex. Penal Code Ann. § 31.11 ...................................................................................9

Wash. Rev. Code Ann. § 9.41.092...........................................................................11

Wash. Rev. Code Ann. § 9.41.111...........................................................................11

Wash. Rev. Code Ann. § 9.41.113...........................................................................11

2022 Wash. Sess. Laws ch. 105 (S.H.B. 1705) ................................................ 10, 11

Newspapers and Media Reports

Andrew Blankstein & Eric Leonard, Ex-con who killed California cop used

homemade ‘ghost gun,’ NBC News (Aug. 15, 2019).........................................15

Brad Brooks, California school shooting shines light on murky ‘ghost gun’ 

world, Reuters (Nov. 22, 2019) ..........................................................................15

Ryan Hill, ‘Ghost guns are everywhere’: San Diego’s firefight continues 

to get ghost guns off of the street, ABC 10 News (Feb. 19, 2022).....................12

Jeff Pegues, Rise in crime fueled in part by ‘ghost’ guns, ATF says, 

CBS News (Feb. 2, 2022)...................................................................................12

Brian Saunders, Philadelphia arrests gunmaker as Biden regulates ghost guns, 

Phila. Tribune (Apr. 11, 2022)............................................................................12

Bill Whitaker, Ghost Guns: The build-it-yourself firearms that skirt most federal 

gun laws and are virtually untraceable, CBS News (May 10, 2020)................14

Ovetta Wiggins, Baltimore plans to sue ‘ghost gun’ part maker as state law takes 

effect, Wash. Post (May 31, 2022)......................................................................12

Other Authorities

80% Arms, Buying Guns Online Without An FFL ....................................................6

Cal. Dep’t of Just., Armed and Prohibited Persons System Report 2021 ...............14

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Everytown for Gun Safety, Untraceable: The Rising Specter of 

Ghost Guns (2020)..............................................................................................13

Int’l Ass’n of Chiefs of Police, 2018 Resolutions (Nov. 2018)...............................17

JSDSupply, FNS – Lower Parts Kit, Complete Kits for a Complete Build...............6

JSDSupply, Stealth Arms Parts & Kits....................................................................13

Scott R. Kegler et al., Vital Signs: Changes in Firearm Homicide and 

Suicide Rates – United States, 2019-2020, Morbidity & Mortality 

Weekly Report (May 13, 2022)............................................................................1

Polymer80, 80 Lower...............................................................................................13

Travis Taniguchi et al., Nat’l Police Found., The Proliferation of Ghost

Guns: Regulation Gaps and Challenges for Law Enforcement (2021) .. 12, 13, 14

Franklin E. Zimring, Firearms and Federal Law: The Gun Control Act of 

1968, 4 J. Legal Stud. 133 (1975).....................................................................6, 7

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INTRODUCTION AND INTEREST OF AMICI STATES

The District of Columbia and the States of New Jersey and Pennsylvania, on 

behalf of themselves and the States of California, Colorado, Connecticut,

Delaware, Hawaii, Illinois, Maine, Maryland, Massachusetts, Michigan, 

Minnesota, New York, North Carolina, Oregon, Rhode Island, Washington, and 

Wisconsin (collectively, the “Amici States”), file this brief as amici curiae in 

support of the Bureau of Alcohol, Tobacco, Firearms and Explosives (“ATF”) and 

its authority to enact the Final Rule at issue. See Definition of “Frame or 

Receiver” and Identification of Firearms, 87 Fed. Reg. 24652 (Apr. 26, 2022) (to 

be codified at 27 C.F.R. pts. 447, 478, 479). Amici States’ “dominant interest” in 

“preventing violence . . . cannot be questioned. It is a matter of genuine local 

concern.” United Auto., Aircraft & Agric. Implement Workers of Am. v. Wis. Emp.

Rels. Bd., 351 U.S. 266, 274 (1956).

In recent years, gun violence has exploded across the country. Gun-related 

homicides rose nearly 35 percent between 2019 and 2020, reaching their highest 

level in over 25 years. Scott R. Kegler et al., Vital Signs: Changes in Firearm 

Homicide and Suicide Rates – United States, 2019-2020, Morbidity & Mortality 

Weekly Report (May 13, 2022), https://bit.ly/3yt5X0a. At the same time, advances 

in firearms technology have contributed to the rapid proliferation of “ghost guns”: 

unserialized firearms that can be built at home from easily assembled weapon parts 

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kits or partially complete frames or receivers. Though individual states have 

worked diligently to protect their citizens from gun violence and address this 

emerging threat, there is a natural limit to states’ abilities to combat a nationwide 

problem that crosses state borders. Absent federal enforcement, ghost guns have 

continued to proliferate, including in the very states that have been trying to keep 

them out. Consistent with the federal Gun Control Act of 1968 (“GCA” or “the 

Act”), the Final Rule fills this gap in state-by-state enforcement by expressly

regulating weapon parts kits and partially complete frames or receivers as firearms. 

In doing so, it advances the “twin goals” of the GCA: “to keep guns out of the 

hands of criminals and others who should not have them, and to assist law 

enforcement authorities”—the bulk of whom operate at the state and local level—

“in investigating serious crimes.” Abramski v. United States, 573 U.S. 169, 180 

(2014).

BACKGROUND

To support state and local law enforcement, the GCA regulates the 

possession, manufacture, sale, and transfer of “firearms.” See 18 U.S.C § 921 et 

seq. It generally prohibits certain people, such as felons, domestic abusers, and 

juveniles, from gun possession, id. § 922(g), (x)(2), and it requires federal firearms 

licensees to serialize each firearm, run a background check before every sale, and

record each gun transaction, id. §§ 922(t), 923(g), (i). Because these provisions 

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apply only to “firearms,” what constitutes a firearm is essential to any proper 

interpretation of the Act. The Act defines a “firearm” in relevant part as “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,” or “the frame or 

receiver of any such weapon.” Id. § 921(a)(3).

Recent advances in firearms technology have prompted the ATF to 

reexamine its rules implementing the GCA. In the past few years, the ghost gun 

industry has exploded, driven in large part by the online sale of weapon parts kits. 

These user-friendly kits typically contain nearly complete firearms parts and 

require a minor amount of assembly to become fully functional weapons. 87 Fed. 

Reg. at 24662. As these firearms kits proliferated, so too have self-made, 

unserialized guns. Law enforcement officers went from recovering about 1,700 

self-made guns in 2016 to over 19,000 in 2021, an eleven-fold increase. 87 Fed. 

Reg. at 24656. Altogether, officers recovered about 45,240 self-made guns during

that five-year period—more than 40 percent of which were recovered in 2021 

alone. 87 Fed. Reg. at 24656. The rise of these kits revealed two problems. First, 

a person explicitly banned from gun possession under the GCA could still buy a kit 

and assemble a fully functional gun within hours. Second, because the finished 

product was unserialized, officers could not track the gun if it was later used in a 

crime. Indeed, of the 45,240 suspected ghost guns recovered from 2016 to 2021, 

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only 445 could be traced—a less than one percent success rate. 87 Fed. Reg. at 

24659.

The Final Rule takes important steps to remedy that problem by clarifying 

how the Act’s key terms will be enforced. First, the Rule explicitly includes 

weapon parts kits in its definition of “firearm”:

Firearm. 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; the frame or receiver of any such weapon . . . . The term shall 

include a weapon parts kit that is designed to or may readily be completed, 

assembled, restored, or otherwise converted to expel a projectile by the 

action of an explosive.

87 Fed. Reg. at 24735. Second, the Rule clarifies that a partially complete frame 

or receiver, or a frame or receiver kit, is a “frame” or “receiver” under the GCA if 

it can readily be converted to function as such. 87 Fed. Reg. at 24739. Third, the 

Rule defines “privately made firearm” and “readily” for the first time and

enumerates relevant factors for assessing whether something can “readily” be 

converted to expel a projectile. 87 Fed. Reg. at 24735. And fourth, it provides 

detailed instructions on how and when licensees must mark firearms. 87 Fed. Reg. 

at 24741-42. Notably, the Rule does not ban weapon parts kits or partially 

complete frames or receivers. It merely treats them the same as conventionally 

manufactured guns, and it allows law-abiding citizens to privately assemble guns 

for personal use if they so wish.

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SUMMARY OF ARGUMENT

1. The Final Rule is consistent with the text, history, and purposes of the 

GCA. As the Rule recognizes, readily assembled weapon parts kits or partially 

complete frames or receivers are “firearms” under the statute’s plain text. The 

history and context of the Act confirm this commonsense interpretation. Congress 

enacted a broad scheme to regulate the interstate flow of firearms, and the Rule 

ensures that the Act and similar state laws are not thwarted by advances in gun

technology.

2. The Final Rule is a vital backstop to states’ efforts to stem the flow of 

ghost guns and combat the violence that has resulted. In response to the recent 

influx of ghost guns, at least 14 jurisdictions have enacted their own laws 

regulating weapon parts kits and partially complete frames or receivers. But absent 

federal enforcement, the number of unserialized guns has proliferated, leaving in 

its wake a spike in crime and violence. The Final Rule serves a vital coordinating 

function, consistent with the GCA, that states cannot exercise on their own.

ARGUMENT

I. The Final Rule Fits Squarely Within The GCA’s Comprehensive

Scheme, Which Was Designed To Fill Gaps In State-By-State 

Enforcement.

Under a plain reading of the Act, easy-to-assemble weapon parts kits and 

partially complete frames or receivers fall within the statutory definition of 

“firearm” because they are both “designed to . . . expel a projectile by the action of 

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an explosive,” and “may readily be converted” to do just that. 18 U.S.C. 

§ 921(a)(3). As the ATF recognized, the text focuses on a weapon’s proximity to 

full functionality and not on its immediate ability to fire a projectile. 87 Fed. Reg. 

at 24685; see 18 U.S.C. § 921(a)(3) (defining a “firearm” to include a “starter 

gun,” which are filled with blanks but can readily be converted to fire an 

explosive). Weapon parts kits similarly meet that proximity threshold because 

they are, by design, easy to convert into a fully functional firearm—and in fact, 

they are consistently marketed as practical substitutes to conventional weapons. 

See, e.g., JSDSupply, FNS – Lower Parts Kit, Complete Kits for a Complete Build, 

https://bit.ly/3anxK8N (last visited July 8, 2022) (describing kits as essentially 

“fully functional firearm[s] without the hurdles of a background check or 

government fees”); 80% Arms, Buying Guns Online Without An FFL, 

https://bit.ly/3P9SksZ (last visited July 8, 2022) (urging visitors to “buy a ‘gun’ 

online with 80% Arms!”).

This interpretation is reinforced by the Act’s history and context: ending 

“mail order murder.” H.R. Rep. No. 90-1577, at 19 (1968). At the time, Congress 

and the public were reeling from the high-profile murders of President John F. 

Kennedy, Martin Luther King, Jr., and Robert F. Kennedy, whose deaths focused 

attention on mail-order guns and helped pressure Congress to act. Franklin E. 

Zimring, Firearms and Federal Law: The Gun Control Act of 1968, 4 J. Legal 

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Stud. 133, 147-48 (1975). Congress thus passed the GCA to curb easy access to 

these deadly weapons and solve the “interstate mail order gun problem.” Id. at 145

(citing an unpublished report from Senator Thomas Dodd). The GCA must be read 

in light of that context and overall scheme. See FDA v. Brown & Williamson 

Tobacco Corp., 529 U.S. 120, 133 (2000). That means adopting a commonsense, 

functional understanding of “firearm” that considers proximity to full use and 

recognizes the crucial anti-circumvention role that the GCA was designed to play.

The Final Rule fits within the GCA’s purpose of closing the gaps that led to 

widespread interstate trafficking of firearms to unknown individuals despite state 

laws intended to prevent those problems. In the same way that mail-order guns 

previously enabled “criminals, immature juveniles, and other irresponsible 

persons” to obtain firearms when “they could not purchase guns under the laws in 

their own jurisdictions,” Zimring, supra at 145, the unregulated supply today of 

unserialized gun parts lets people evade the gun laws of their states. This modern 

incarnation of the mail-order gun problem also undermines the purposes of the 

GCA: to “control the indiscriminate flow of [guns] across State borders” and to 

“[e]nsure that strong local or State laws are not subverted by a deadly interstate 

traffic in firearms.” H.R. Rep. No. 90-1577, at 8, 19 (1968).

For example, according to a House Judiciary Committee Report, Congress 

banned the “interstate mail-order shipments of firearms . . . so that State and local

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authorities may better exercise the controls they deem desirable over . . . such 

firearms.” H.R. Rep. No. 90-1577, at 12 (emphasis added) (explaining 18 U.S.C. 

§ 922(a)(2)). Legislators also banned licensees from selling to persons barred from 

gun ownership in the state where the licensee does business—as well as to those 

who the licensee believes do not reside in that state—to close a recurring loophole 

in state-only enforcement: “the avoidance of State and local laws controlling 

firearms by the simple expediency of crossing a State line to purchase one.” Id. at 

14 (emphasis added) (explaining 18 U.S.C. § 922(b)(2)-(3)). At bottom, the GCA 

was meant to protect the integrity of state gun laws against interstate 

circumvention—a task Congress correctly recognized was uniquely suited for the 

federal government:

[C]ontrols on interstate gun traffic which only the Federal 

Government can apply, and without which no State gun law is worth 

the paper it is written on[,] [are vital]. . . . . Without such Federal 

assistance, any State gun law c[ould] be subverted by any child, 

fugitive, or felon who orders a gun by mail or buys one in a 

neighboring State which has lax gun laws.

114 Cong. Rec. 13647 (1968) (statement of Sen. Joseph Tydings).

If the GCA was crafted to solve a circumvention problem presented by mailorder guns, then it must also be read to solve an identical circumvention problem 

presented by ghost guns. Indeed, the Supreme Court has instructed courts to 

interpret the GCA practically, to focus on “substance” and not “empty formalities.” 

Abramski, 573 U.S. at 180. By updating the GCA’s critical definitions to cover 

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advances in firearms technology, the Final Rule is faithful to that guidance. See 

infra Section II.C.

II. The Final Rule Complements State Efforts To Regulate Unserialized 

Firearms.

Absent federal regulation, unserialized firearms have flooded Amici States’ 

communities. Many of these weapons end up in the hands of people banned from 

gun ownership, directly undermining the GCA’s core provisions as well as state 

law. See 87 Fed. Reg. at 24657 n.20. At the same time, gun violence and 

homicides have spiked in recent years. In response to this influx, many states 

(including Amici States) have passed laws regulating weapon parts kits and 

partially complete frames or receivers. The Final Rule lends critical federal 

support to these existing state efforts.1

A. At least 14 jurisdictions, including the District, have passed their 

own laws regulating kits and other unserialized firearms.

As the primary actors charged with “defining and enforcing criminal laws,” 

states are responsible for addressing the violence associated with weapon parts kits 

and their resulting firearms. Torres v. Lynch, 578 U.S. 452, 464 n.9 (2016)

1 A broad group of states has long recognized the problem posed by 

unserialized guns, and many criminalize the removal of a serial number from a 

firearm (or the possession of a firearm so altered). See, e.g., Ala. Code 

§ 13A-11-64; Mont. Code Ann. § 45-6-326; Neb. Rev. Stat. §§ 28-1207, -1208; 

Ind. Code § 35-47-2-18; S.D. Codified Laws § 22-14-5; Tex. Penal Code Ann. 

§ 31.11.

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(internal quotation mark and citation omitted). In light of the surge of kits and 

unserialized guns, states have targeted the possession, manufacture, and transfer of 

such firearms, and have imposed detailed marking and recordkeeping requirements 

on licensees.

For example, at least thirteen jurisdictions target the possession of 

unserialized firearms. Three specifically define and target the possession of any 

“ghost gun.” See D.C. Code §§ 22-4514, 7-2501.01(9B); N.Y. Penal Law 

§ 265.01(9)-(10); R.I. Gen. Laws Ann. §§ 11-47-8(e), -2(8). Others do the same, 

albeit using different language.2 And at least one state prohibits people who are 

otherwise banned from gun ownership from also possessing an unserialized frame 

or receiver or similar component part. See Conn. Gen. Stat. Ann. § 53-206j(f).

At least eight states also target the ghost gun manufacturing and assembly 

process. One prescribes a detailed scheme for regulating self-manufacturing—

specifically, requiring someone to apply for a unique serial number from the state, 

engrave that number on the gun’s frame or receiver, and pass a background check. 

See Conn. Gen. Stat. Ann. §§ 29-36a, 53-206j. Four others prohibit the 

2 See, e.g., Cal. Penal Code §§ 16519, 16531, 30400; Del. Code Ann. 

tit. 11, § 1459A(b); Haw. Rev. Stat. Ann. § 134-10.2; 720 Ill. Comp. Stat. Ann.

5/24-5.1(c), (d); Md. Code Ann., Pub. Safety § 5-703(b)(2); Minn. Stat. Ann. 

§ 609.667(3); Nev. Rev. Stat. Ann. § 202.363; N.J. Stat. Ann. § 2C:39-9(k); 2022 

Wash. Sess. Laws ch. 105 § 4 (S.H.B. 1705) (to be codified at Wash. Rev. Code 

Ann. § 9.41).

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manufacturing of an untraceable firearm or the acquisition of certain component 

parts for the purpose of building a firearm. See Cal. Penal Code §§ 16519, 16531, 

30400; Haw. Rev. Stat. Ann. § 134-10.2; N.J. Stat. Ann. § 2C:39-9(k); 2022 Wash. 

Sess. Laws ch. 105 § 4 (S.H.B. 1705) (to be codified at Wash. Rev. Code Ann. 

§ 9.41). The rest have more generalized restrictions.3

Many states also target the sale and transport of unserialized firearms and 

their component parts. At least twelve jurisdictions criminalize the sale or transfer 

of unserialized firearms and partially complete frames or receivers, either generally 

or when transferred to non-licensees or prohibited persons.4 And many states place 

detailed restrictions on dealers at the point of sale, using background checks, 

recordkeeping, and serialization requirements.5

3 See, e.g., Mass. Gen. Laws ch. 269, § 11E; Nev. Rev. Stat. Ann. 

§ 202.3635; R.I. Gen. Laws Ann. § 11-47-8(e).

4 See Cal. Penal Code § 30400; Conn. Gen. Stat. Ann. § 29-36a(d); Del. 

Code Ann. tit. 11, § 1459A; D.C. Code §§ 7-2504.08(a), 7-2505.01-.02; Haw. Rev. 

Stat. § 134-10.2; 720 Ill. Comp. Stat. Ann. 5/24-5.1(b); Md. Code Ann., Pub. 

Safety § 5-703(a)(1)-(2); Mass. Gen. Laws ch. 269, § 11E; Nev. Rev. Stat. Ann. 

§§ 202.3625, .364; N.J. Stat. Ann. § 2C:39-9(n); N.Y. Penal Law §§ 265.60-.64; 

R.I. Gen. Laws Ann. § 11-47-8(e).

5 See, e.g., Cal. Penal Code §§ 29180, 29182; Del. Code Ann. tit. 11, 

§§ 1448A, 1448B, 1459A; 720 Ill. Comp. Stat. Ann. 5/24-5.1; Md. Code Ann., 

Pub. Safety § 5-703; Mass. Gen. Laws ch. 269, § 11E; N.J. Stat. Ann. § 2C:58-2; 

N.Y. Penal Law § 265.07; R.I. Gen. Laws Ann. § 11-47-40; 2022 Wash. Sess. 

Laws ch. 105 § 6 (S.H.B. 1705) (to be codified at Wash. Rev. Code Ann. § 9.41); 

Wash. Rev. Code Ann. §§ 9.41.092, .111, .113.

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B. Despite state efforts, the number of unserialized firearms has 

grown exponentially.

Absent federal enforcement, however, states and other localities (including 

those with laws targeting ghost guns) have continued to see self-assembled, 

unserialized firearms flow into their communities. For example, in 2018, six

different police agencies reported the following ghost gun recovery numbers: San 

Diego (53), the District of Columbia (25), Chicago (21), New York City (18), 

Philadelphia (17), and Prince George’s County, Maryland (17). Travis Taniguchi

et al., Nat’l Police Found., The Proliferation of Ghost Guns: Regulation Gaps and 

Challenges for Law Enforcement 15 (2021) (hereinafter “NPF Report”), 

https://bit.ly/3yLOFLz. Three years later, in 2021, those numbers skyrocketed—

even in states regulating ghost guns—with the same agencies reporting ten- to 

thirty-fold increases: San Diego (545), District of Columbia (439), Chicago (455), 

New York City (225), Philadelphia (571), and Prince George’s County (264).6 

Across the country, the story is the same: federal recovery numbers for 

6 See Ryan Hill, ‘Ghost guns are everywhere’: San Diego’s firefight 

continues to get ghost guns off of the street, ABC 10 News (Feb. 19, 2022), 

https://bit.ly/3M6YcjS (San Diego); Data on file with the Metropolitan Police 

Department (current as of June 29, 2022) (District of Columbia); Jeff Pegues, Rise 

in crime fueled in part by ‘ghost’ guns, ATF says, CBS News (Feb. 2, 2022), 

https://cbsn.ws/3NPmkbp (Chicago and New York City); Brian Saunders, 

Philadelphia arrests gunmaker as Biden regulates ghost guns, Phila. Tribune (Apr. 

11, 2022), https://bit.ly/3NCFmTh (Philadelphia); Ovetta Wiggins, Baltimore 

plans to sue ‘ghost gun’ part maker as state law takes effect, Wash. Post (May 31, 

2022), https://wapo.st/3PXsrwU (Prince George’s County).

Case 4:22-cv-00691-O Document 47-1 Filed 08/30/22 Page 19 of 28 PageID 594
13

unserialized guns have soared, jumping eleven-fold between 2016 and 2021. 87 

Fed. Reg. at 24656.

The number of ghost gun sellers has also proliferated, making these weapons 

increasingly accessible. According to the ATF, there are about 129 companies 

selling weapon parts kits or partially complete frames or receivers. See 87 Fed. 

Reg. at 24718. These companies operate in 27 states across the country. NPF 

Report 2. And the number of ghost gun sellers has been steadily increasing for 

years—a phenomenon that tracks the increasing spread of ghost guns nationwide. 

See Everytown for Gun Safety, Untraceable: The Rising Specter of Ghost Guns 13 

(2020), https://bit.ly/3m6LRBt (finding 26 ghost gun sellers in 2014 compared to 

80 sellers by 2020). Moreover, weapon parts kits are affordable and user friendly, 

with some costing less than $100 and requiring only “a few tools” and “basic 

instructions” to “build a fully functional firearm.” JSDSupply, Stealth Arms Parts 

& Kits, https://bit.ly/3yhxQGY (last visited July 8, 2022); see Polymer80, 80 

Lower, https://bit.ly/3PZCS2M (last visited July 8, 2022).

This combination of widespread access and federal inaction has made it 

easier for individuals to circumvent state gun laws, bringing unserialized weapons 

into the very states that have been trying to keep them out. For example, even 

though California has attempted to curb unserialized guns since at least 2016, these 

weapons accounted for nearly 30 percent of all guns recovered in the state by the 

Case 4:22-cv-00691-O Document 47-1 Filed 08/30/22 Page 20 of 28 PageID 595
14

ATF. NPF Report 5. Meanwhile, the number of unserialized guns recovered by 

California law enforcement agencies increased from 167 in 2016 to nearly 12,400

in 2021, a 74-fold increase. Cal. Dep’t of Just., Armed and Prohibited Persons 

System Report 2021 at 26, https://bit.ly/3uljKDs (last visited July 8, 2022). 

According to local authorities, that is because guns are easily trafficked across the 

state’s borders. See Bill Whitaker, Ghost Guns: The build-it-yourself firearms that 

skirt most federal gun laws and are virtually untraceable, CBS News (May 10, 

2020), https://cbsn.ws/3Li5zoM (interviewing the Los Angeles County Sheriff). 

Similarly, New Jersey has regulated unserialized firearms since at least 2018. But 

at the same time, the state has seen large increases in the number of ghost guns 

recovered at crime scenes, from 55 guns in 2019 to 101 in 2020 and 255 in 2021.7 

More troubling, nearly all ghost guns recovered in New Jersey were assembled 

from kits manufactured out of state, and many were used to commit violent crimes 

(including murder and aggravated assault).8

The Final Rule helps curb that phenomenon, advancing the GCA’s core aims 

at a time when federal assistance is critical. Without banning the sale of kits or 

self-manufactured guns, the Rule ensures that states can at least trace these 

7 Data on file with New Jersey State Police (current as of May 5, 2022).

8 Data on file with New Jersey State Police (current as of May 5, 2022).

Case 4:22-cv-00691-O Document 47-1 Filed 08/30/22 Page 21 of 28 PageID 596
15

weapons and that they are not bought by criminals or children as a means of 

evading state law.

C. The Final Rule closes the gaps inherent in state-by-state 

enforcement.

The Final Rule addresses the problems that have contributed to this alarming 

proliferation of untraceable guns in multiple ways. First, by updating the Act’s 

definitions, the Rule ensures that sellers run a background check on potential 

purchasers before delivering a kit or nearly complete frame or receiver. This 

makes it harder for prohibited persons to acquire a gun and thus safeguards the 

numerous federal and state laws that have excluded certain people from gun 

ownership.9

Indeed, without meaningful federal oversight, unserialized guns have 

regularly fallen into the hands of prohibited persons, with often deadly results. In 

2019, for example, a 16-year-old boy killed two classmates and himself with a gun 

that had been assembled from a kit. Brad Brooks, California school shooting 

shines light on murky ‘ghost gun’ world, Reuters (Nov. 22, 2019), 

https://reut.rs/3MO4fuc. That same year, a man with multiple felony convictions 

used a self-made semi-automatic rifle, assembled from parts, to kill one police 

officer and injure two others. Andrew Blankstein & Eric Leonard, Ex-con who 

9 See, e.g., 18 U.S.C. § 922(g); Del. Code Ann. tit. 11, § 1448; D.C. 

Code § 22-4503; Nev. Rev. Stat. Ann. § 202.360; N.J. Stat. Ann. § 2C:58-3(c).

Case 4:22-cv-00691-O Document 47-1 Filed 08/30/22 Page 22 of 28 PageID 597
16

killed California cop used homemade ‘ghost gun,’ NBC News (Aug. 15, 2019), 

https://nbcnews.to/3vLC09U. The data tell a similar story.10 By exerting the 

ATF’s authority over kits and readily convertible frames or receivers, the Final 

Rule helps keep these guns away from felons and children, consistent with 

Congress’s intent. See supra Part I.

Second, the Final Rule ensures that licensees mark kits and nearly complete 

frames or receivers with a unique serial number and keep records of all relevant 

transactions. Tracing is a critical law enforcement tool, and over 8,600 law 

enforcement agencies across 46 countries rely on the ATF’s web-based tracing 

application. 87 Fed. Reg. at 24659. But that service has limited utility if a large 

number of unserialized guns are excluded and federal and state record-keeping 

laws are not enforced. See 18 U.S.C. § 923(g); see also supra Part II.A. The 

effective administration of justice will be thwarted if prosecutors cannot trace guns 

and use such evidence to enforce the Act’s provisions against straw purchasers, 

firearms traffickers, and gun thieves. See 87 Fed. Reg. at 24660.

10 In New Jersey, nearly 40 percent of all people arrested with a ghost 

gun from 2021 to mid-2022 had been banned from gun ownership because of their 

criminal records. Data on file with New Jersey State Police (current as of May 5, 

2022). In Philadelphia, roughly half of the 478 people arrested in 2021 for the 

possession or use of a ghost gun had been banned because of disqualifying 

convictions, including violent felonies. Data on file with the Pennsylvania Office 

of the Attorney General (current as of May 17, 2022).

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17

Third, the Final Rule may also help states apply their own laws to avoid gaps 

that would allow ghost guns to proliferate. State authorities often follow the 

ATF’s lead when drafting or assessing the scope of their own gun laws. See, e.g., 

Cal. Penal Code § 16519 (defining a key term based on federal gun regulations); 

Moore v. State, 983 A.2d 583, 595 (Md. Ct. Spec. App. 2009) (explaining that the 

state legislature enacted certain gun laws expecting they would be read “consistent 

with federal law”). This ripple effect makes the Final Rule even more critical to 

state gun schemes, as it not only fills the gaps in enforcement described above, but 

also helps states interpret or revise their own gun laws, in keeping with Congress’s 

intent. H.R. Rep. No. 90-1577, at 8, 12.

The Final Rule helps stop a growing segment of the modern gun industry 

from exploiting new technology to widen the very gaps that the GCA sought to 

close. It is therefore no surprise that law enforcement “strongly supports” efforts 

to treat ghost guns the same as other firearms. Int’l Ass’n of Chiefs of Police, 

2018 Resolutions 15 (Nov. 2018), https://bit.ly/3vya4Fb. The Final Rule makes 

crucial clarifications to the GCA’s definitions and helps states fulfill their “very 

highest duty” to safeguard the lives and well-being of their citizens. United States 

v. Cruikshank, 92 U.S. 542, 553 (1875). It falls squarely within the GCA’s

framework and should be upheld.

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18

CONCLUSION

This Court should deny the plaintiffs’ motion for injunctive relief.

Case 4:22-cv-00691-O Document 47-1 Filed 08/30/22 Page 25 of 28 PageID 600
19

Dated: August 30, 2022

 Respectfully submitted, 

MATTHEW J. PLATKIN

Acting Attorney General 

for the State of New Jersey

MELISSA MEDOWAY

Special Litigation Chief

Deputy Attorney General

TIM SHEEHAN

Deputy Attorney General

The Office of the Attorney 

General of New Jersey

Richard J. Hughes Justice 

Complex

25 Market Street, P.O. Box 112

Trenton, NJ 08625

(609) 376-3232

melissa.medoway@njoag.gov

JOSH SHAPIRO

Attorney General for the 

Commonwealth of Pennsylvania

JACOB B. BOYER

Deputy Attorney General

Office of the Attorney General 

for the Commonwealth of 

Pennsylvania

1600 Arch Street, Suite 300 

Philadelphia, PA 19103 

(267) 768-3968

jboyer@attorneygeneral.gov

KARL A. RACINE

Attorney General for the District of 

Columbia

CAROLINE S. VAN ZILE*

Solicitor General

ASHWIN P. PHATAK

Principal Deputy Solicitor General

Office of the Solicitor General

Office of the Attorney General 

for the District of Columbia

400 6th Street, NW, Suite 8100

Washington, D.C. 20001

(202) 724-6609

caroline.vanzile@dc.gov

/s/ Will Thompson

Will Thompson

TX State Bar No. 24094981

Quinn Emanuel Urquhart & Sullivan, LLP

3100 McKinnon Street, Suite 1125

Dallas, TX 75201

(469) 902-3200

(469) 902-3610 (fax)

willthompson@quinnemanuel.com

Local Counsel

*Pro hac vice application forthcoming

Case 4:22-cv-00691-O Document 47-1 Filed 08/30/22 Page 26 of 28 PageID 601
20

On behalf of: 

ROB BONTA

Attorney General

State of California

WILLIAM TONG

Attorney General

State of Connecticut

HOLLY T. SHIKADA

Attorney General

State of Hawaii

AARON M. FREY

Attorney General

State of Maine

MAURA HEALEY

Attorney General

Commonwealth of 

Massachusetts

KEITH ELLISON

Attorney General

State of Minnesota

JOSHUA H. STEIN

Attorney General

State of North Carolina

PETER F. NERONHA

Attorney General

State of Rhode Island

JOSHUA L. KAUL

Attorney General

State of Wisconsin

PHILIP J. WEISER

Attorney General

State of Colorado

KATHLEEN JENNINGS

Attorney General

State of Delaware

KWAME RAOUL

Attorney General

State of Illinois

BRIAN E. FROSH

Attorney General

State of Maryland

DANA NESSEL

Attorney General

State of Michigan

LETITIA JAMES

Attorney General

State of New York

ELLEN F. ROSENBLUM

Attorney General

State of Oregon

ROBERT W. FERGUSON

Attorney General

State of Washington

Case 4:22-cv-00691-O Document 47-1 Filed 08/30/22 Page 27 of 28 PageID 602
21

CERTIFICATE OF SERVICE

I hereby certify that on August 30, 2022, a true and accurate copy of the 

foregoing brief was filed electronically with the Court using the CM/ECF system. 

Notice of this filing will be sent to all parties for whom counsel has entered an 

appearance by operation of the Court’s electronic filing system.

/s/ Will Thompson

Will Thompson

Case 4:22-cv-00691-O Document 47-1 Filed 08/30/22 Page 28 of 28 PageID 603