Mastagni Holstedt, APC was privileged to file an amicus curiae brief in the Supreme Court of the United States on behalf of the Peace Officers Research Association of California, the California Association of Highway Patrolmen, and the Crime Prevention Research Center in Viramontes v. Cook County, No. 25-238. The brief supports the petitioners’ challenge to Cook County’s semiautomatic rifle ordinance and to Illinois’s Protect Illinois Communities Act. Those restrictions track California’s assault weapon statutes. They also bear on pending Ninth Circuit challenges to the Unsafe Handgun Act’s feature-based ban on most modern handguns. PORAC and CAHP have filed a brief in that appeal challenging the constitutionality of the UHA. Viramontes will also determine whether California peace officers may retain, after retirement, the same commonly owned rifles they lawfully carried in public service.
The organizations speak from professional experience rather than from a partisan political perspective. PORAC and CAHP represent rank and file officers who enforce firearms laws every day, the men and women who run toward gunfire. CPRC conducts rigorous academic crime research. Their shared perspective supports sound public policy that disarms prohibited persons, confines violent offenders through firearm enhancements, and protects the self-defense rights of law-abiding citizens. They reject the approach of blaming the tools of self-defense while excusing the failure of state officials to enforce existing laws and to impose consequences on violent criminals.
Common Use Ends the Inquiry
The Second Amendment’s text covers the keeping and bearing of arms. Once that threshold is met, the government must demonstrate a historical tradition of comparable regulation. District of Columbia v. Heller, 554 U.S. 570 (2008); New York State Rifle & Pistol Ass’n v. Bruen, 597 U.S. 1 (2022). Arms “in common use” for lawful purposes may not be banned. That protection reaches even arms unknown at the founding, subject only to the limitation that “dangerous and unusual” weapons not “in common use” may be restricted.
AR-15 platform rifles satisfy that test because they are in common use. Americans own an estimated twenty to thirty million of them. They are lawful in forty-one States. Owners keep them for self-defense, target shooting, hunting, and pest control. Their ergonomics, modest recoil, and accuracy make them well suited to defense of the home. A firearm tens of millions of responsible citizens have chosen is not “dangerous and unusual.” Laws that treat these rifles as the functional equivalent of machine guns cannot be reconciled with Heller.
The Data on Gun Crime Refutes the Safety Rationale
The States defend these bans as necessary public safety measures. The empirical record does not support that claim. Criminals rarely obtain firearms through the lawful retail channels these statutes regulate. Bureau of Justice Statistics prisoner surveys show that most offenders who used a gun stole it, found it, or bought it on the street or in the underground market.
Rifles of every type account for a small and shrinking share of homicides. In 2025, of 16,091 murders in which the weapon was identified, only 494 involved a rifle or shotgun. That is fewer than 3.1 percent. The rifle share of firearm murders was 4.8 percent before the 1994 federal assault weapons ban, 4.9 percent while that ban was in effect, and 3.6 percent afterward, even as civilian ownership of AR-15s and similar platforms rose sharply.
Handguns, not rifles, are used in most felonious killings of officers. The rifle share did not fall during the decade of the federal ban.
National Institute of Justice evaluations of the 1994 ban found no discernible reduction in gun violence or in the lethality of gun crime. Independent state-level work controlling for preexisting differences and other gun laws reached the same conclusion. RAND’s synthesis and a 2005 systematic review in the American Journal of Preventive Medicine found no significant evidence that assault weapon restrictions reduce violent crime, homicide, or mass shootings. Mass public shooting data from 1998 through 2025 show that a majority of attacks used only handguns. Rifles of any type appeared in a minority of incidents. The deadliest attacks typically involved multiple weapon types rather than a single banned rifle.
Although the effectiveness of these rifle bans is not the historical test applied by the Court, the data is presented to refute the false premises used to enact these statutes.
California Extinguishes the Officer’s Right at Retirement
Peace officers and their families face reprisal risks that do not end with their shift or at retirement. California nevertheless treats possession of these arms as a revocable employment privilege. An officer may possess a registered “assault weapon” only while employed by a qualifying agency and only upon the agency head’s written certification of the specific firearm. Off-duty possession is confined to limited locations absent a Department of Justice permit. When employment ends, the right collapses. Cal. Penal Code §§ 30625, 30630(a), (b)(1)–(2), 30945(a)–(g), 31000(a)–(c).
Within ninety days the departing officer must permanently disable the rifle, sell it to a licensed dealer, obtain a difficult permit, or remove it from the State. Registered weapons may not be transferred to anyone in California except a licensed dealer. Weapons surrendered to law enforcement are forfeited for destruction. Cal. Penal Code §§ 30915(a)–(d), 30910, 30605. California thus forbids the officer simply to keep at home the rifle he or she lawfully acquired, registered, and carried for years of public service. Federal LEOSA grants qualified retired officers a nationwide concealed carry right, but it leaves the State’s possession ban intact. 18 U.S.C. §§ 926B, 926C.
The contradiction is dispositive of the safety rationale. If a trained, vetted, background-checked officer may carry the arm on duty for decades, there is no principled basis to treat that same officer as too dangerous to own it in retirement, or to deny it to any other law-abiding citizen.
Feature Bans Are Designed to Evade Heller
When a legislature cannot ban a common firearm by name, it bans ordinary commercial features instead. Those features include pistol grips, folding or telescoping stocks, flash suppressors, and detachable magazines. The feature prohibition does the work of banning the arm. California has carried that method furthest. It first applied the approach to rifles, then to standard capacity magazines, and then to most modern handguns through the UHA. Few, if any, California officers carry a handgun that meets the UHA requirements, even though they carry those same purportedly unsafe handguns on duty, when they are most likely to use them for self-defense. The result is a de facto freeze on new semiautomatic handguns even as agencies issue those same “unsafe” pistols for duty. Boland v. Bonta, 662 F. Supp. 3d 1077 (C.D. Cal. 2023). PORAC and CAHP filed a brief in the Ninth Circuit challenging the UHA in Boland.
A ban on a feature is, in operation, a ban on every common arm that bears it. Heller’s common-use test therefore resolves the question. Even if the Court proceeds to Bruen’s “how and why” inquiry, the bans fail. Reducing firearm misuse is a concern as old as the Republic. The Founders could have banned common arms and did not. No founding-era tradition supports prohibiting possession of arms in common use, whether the prohibition is labeled by model or by feature. United States v. Rahimi, 602 U.S. 680 (2024), confirms that the Nation’s tradition properly targets dangerous persons, not the common arms responsible citizens choose. PORAC and CAHP support Rahimi. A State cannot, however, erase Second Amendment rights through incremental hardware mandates. In the Court’s words, a right that can be erased in that manner is no constitutional guarantee at all. Heller, 554 U.S. at 635.
California Restricts the Law-Abiding While Relaxing Enforcement Against the Violent
California legislates aggressively against citizens who obey the law. At the same time, the State exhibits no equivalent zeal for keeping firearms from prohibited persons. It made once-mandatory firearm enhancements discretionary. It directed courts to dismiss enhancements in the furtherance of justice and to give great weight to circumstances favoring dismissal. It opened parole and resentencing pathways for certain individuals serving life without parole for serious, often firearm-related, offenses. The recent Glock ban was prompted by a Sacramento mass shooting committed by a violent felon released from prison six years early. Nevertheless, California tolerates widespread nonenforcement of laws already barring felons from possessing any firearm. Its Armed and Prohibited Persons System carries a backlog of approximately 24,000 individuals known to possess firearms unlawfully.
The cost is not hypothetical. On June 14, 2022, two El Monte police officers were murdered by a gang member who should have been imprisoned on a prior firearm possession arrest. He went free when the district attorney declined to enforce prohibited-persons laws.
A government serious about gun violence prosecutes armed felons. It does not ban common rifles from law-abiding people, and it does not disarm retired peace officers.
What a Favorable Ruling Would Mean for California Officers
A reversal would confirm that arms in common use may not be banned and that feature-based restrictions are measured by their burden rather than their label. The same principle would reach pending challenges to California’s assault weapon statutes, magazine limits, and the Unsafe Handgun Act. Officers who spent careers carrying these rifles would no longer be required to disable, sell, or exile them the day the badge comes off. Law-abiding citizens would regain access to the Nation’s most popular defensive rifles.
Amici ask the Court to hold that these statutes violate the Second Amendment. The brief reflects the work of David E. Mastagni and Alexandra Holland of Mastagni Holstedt, APC, and Timothy K. Talbot and Michael A. Morguess of RLSSS. This blog will continue to report on the case as it develops. Our firm is proud to stand with amici on this case of national importance.
