Assault Weapons and Large-Capacity Magazines

This page collects resources for defending laws that regulate assault weapons and large-capacity magazines against Second Amendment challenges—including a selection of cases, briefs, historical laws, academic articles, and social science. Additional resources will be added over time. Historical laws are also available at the Repository of Historical Gun Laws at Duke Law School. Please get in touch with any questions you might have about these resources, methodology in Second Amendment cases, or any other issues you confront in defending gun safety laws.

A selection of expert witnesses, unaffiliated with Everytown, who have provided evidence in cases defending assault weapon and large-capacity magazine restrictions against Second Amendment challenges is available here.

Cases

Supreme Court

The Supreme Court has granted certiorari in two Second Amendment challenges to restrictions on assault weapons, Viramontes v. Cook County and Grant v. Higgins. These cases are consolidated, with the following Question Presented: “Whether the Second and Fourteenth Amendments guarantee the right to possess AR-15 platform and similar semiautomatic rifles.”

Courts of Appeals

The following is a selection of significant appellate decisions since the Supreme Court’s 2022 ruling in New York State Rifle & Pistol Ass’n v. Bruen, 597 U.S. 1 (2022), involving Second Amendment challenges to laws restricting assault weapons and/or large-capacity magazines:

1. National Ass’n for Gun Rights v. Lamont, 153 F.4th 213 (2d Cir. 2025), petition for cert. filed, No. 25-421 (Oct. 3, 2025) (assault weapons and large-capacity magazines)
   • Issue: challenge to Connecticut laws restricting assault weapons and large-capacity magazines over 10 rounds
   • Procedural posture: appeal from denial of preliminary injunction
   • Holding: Connecticut’s laws upheld because:
     • At history step of Bruen-Rahimi analysis, it is consistent with the nation’s longstanding traditions of restricting “novel weapons that are particularly suited for criminal violence” and  “unusually dangerous weapons of their day;” and
     • Plaintiffs failed to establish non-merits requirements for preliminary injunction
2. Capen v. Campbell, 134 F.4th 660 (1st Cir. 2025) (assault weapons and large-capacity magazines)
   • Issue: challenge to Massachusetts laws restricting assault weapons and large-capacity magazines over 10 rounds
   • Procedural posture: appeal from denial of preliminary injunction
   • Holding: Massachusetts’s law upheld at history step of Bruen-Rahimi analysis because:
     • Massachusetts’s assault weapon prohibition continues tradition of “protect[ing] the public from the danger caused by weapons that create a particular public safety threat,” including historical regulations of Bowie knives, sawed-off shotguns, and machine guns; and
     • Challenge to Massachusetts’s large-capacity magazine restriction is foreclosed by Ocean State Tactical, LLC v. Rhode Island, 95 F.4th 38 (1st Cir. 2024)
3. Duncan v. Bonta, 133 F.4th 852 (9th Cir. 2025) (en banc), petition for cert. filed, No. 25-198 (Aug. 15, 2025) (large-capacity magazines)
   • Issue: challenge to California law restricting large-capacity magazines over 10 rounds
   • Procedural posture: appeal from order granting summary judgment to plaintiffs, denying summary judgment to California, and entering permanent injunction
   • Holding: California’s law is constitutional because:
     • It is consistent with the Second Amendment at both steps of the Bruen–Rahimi analysis:
       • At text step, “large-capacity magazines are neither weapons nor accessories that are necessary to the operation of a weapon,” and thus “the Second Amendment’s plain text does not protect [their] possession”;
       • At history step, California’s law fits within the nation’s historical traditions of “protecting innocent persons by restricting a component necessary to the firing of a firearm and by restricting especially dangerous uses of weapons when those uses have proved particularly harmful”; and
     • Plaintiffs’ Takings Clause challenge also fails
4. Hanson v. District of Columbia, 120 F.4th 223 (D.C. Cir. 2024), cert. denied, 145 S. Ct. 2778 (2025) (large-capacity magazines)
   • Issue: challenge to D.C. law restricting large-capacity magazines over 10 rounds
   • Procedural posture: appeal from denial of preliminary injunction
   • Holding: D.C.’s law upheld because:
     • At history step of Bruen-Rahimi analysis, it is consistent with the nation’s history and tradition of regulating weapons that are “particularly dangerous,” “particularly capable of unprecedented lethality,” or “that are particularly susceptible to, and were widely used for, multiple homicides and mass injuries”; and
     • Plaintiffs failed to establish non-merits requirements for preliminary injunction
5. Bianchi v. Brown, 111 F.4th 438 (4th Cir. 2024) (en banc), cert. denied, 145 S.Ct. 1534 (2025) (assault weapons)
   • Issue: challenge to Maryland law restricting assault weapons
   • Procedural posture: appeal from order dismissing complaint
   • Holding: Maryland’s law is constitutional at both text and history steps of Bruen-Rahimi analysis because:
     • Assault weapons are “military-style weapons” that are “ill-suited and disproportionate to the need for self-defense” and thus fall outside the scope of the Second Amendment; and
     • Maryland’s law also adheres to our nation’s “strong tradition of regulating excessively dangerous weapons”
6. Delaware State Sportsmen’s Ass’n v. Delaware Department of Safety & Homeland Security, 108 F.4th 194 (3d Cir. 2024), cert. denied, 145 S. Ct. 1049 (2025) (assault weapons and large-capacity magazines)
   • Issue: challenge to Delaware laws restricting assault weapons and large-capacity magazines over 17 rounds
   • Procedural posture: appeal from denial of preliminary injunction
   • Holding: Plaintiffs were not entitled to a preliminary injunction because they failed to establish irreparable harm and other non-merits requirements for preliminary injunction; did not reach merits of Second Amendment claims
     • In a concurring opinion, Judge Roth explained that she also would have rejected plaintiffs’ challenge on the merits, at both text and history steps of Bruen-Rahimi analysis
7. Ocean State Tactical, LLC v. Rhode Island, 95 F.4th 38 (1st Cir. 2024), cert. denied, 145 S. Ct. 2771 (2025) (large-capacity magazines)
   • Issue: challenge to Rhode Island law restricting large-capacity magazines over 10 rounds
   • Procedural posture: appeal from denial of preliminary injunction
   • Holding: Rhode Island’s law upheld because:
     • At history step of Bruen analysis, it is consistent with the nation’s history and tradition, including “the historical regulation of gunpowder storage and of weapons like sawed-off shotguns, Bowie knives, M-16s, and the like”; and
     • Plaintiffs’ Takings Clause and due process retroactivity and vagueness challenges also fail
8. Bevis v. City of Naperville, 85 F.4th 1175 (7th Cir. 2023), cert. denied, 144 S. Ct. 2491 (2024) (assault weapons and large-capacity magazines)
   • Issue: challenges to Illinois law restricting assault weapons and large-capacity magazines over 10 rounds (long guns) and over 15 rounds (handguns) and similar local ordinances
   • Procedural posture: consolidated appeals from denials and grant of preliminary injunction
   • Holding: Illinois’s law and local ordinances upheld at both text and history steps of Bruen analysis because:
     • Plaintiffs failed to show that assault weapons and large-capacity magazines “are Arms that ordinary people would keep at home for purposes of self-defense, not weapons that are exclusively or predominantly useful in military service, or weapons that are not possessed for lawful purposes”; and
     • Challenged state and local laws are also consistent with the nation’s history and tradition of restricting civilian access to “the especially dangerous weapons of the time”
   • Note: See also Viramontes v. County of Cook, No. 24-1437, 2025 WL 1553896 (7th Cir. June 2, 2025) (nonprecedential), petition for cert. filed, No. 25-238 (Aug. 27, 2025) (affirming grant of summary judgment to Cook County in challenge to local assault weapon restriction because challengers “failed to develop a record sufficient to justify a different result” than Bevis)
9. State of Washington v. Gator’s Custom Guns, Inc., 568 P.3d 278 (Wash. 2025) (en banc), petition for cert. filed, No. 25-153 (Aug. 6, 2025) (large-capacity magazines)
   • Issue: challenge to Washington law restricting large-capacity magazines over 10 rounds
   • Procedural posture: appeal from order granting summary judgment to plaintiffs and denying summary judgment to Washington
   • Holding: Washington’s law is constitutional because:
     • It is consistent with the Second Amendment at the text step of the Bruen-Rahimi analysis:
       • Large-capacity magazines are accessories that modify a weapon’s ammunition capacity, “not instruments designed as weapons”;
       • Large-capacity magazines are not commonly used for self-defense; and
       • There is no ancillary Second Amendment right to purchase large-capacity magazines 
     • Also no violation of right to bear arms under Washington Constitution