Colorado Semi-Auto Ban: Permit Rule, Magazines, and Lawsuits

Colorado’s semi-auto ban, signed by Governor Jared Polis on April 10, 2025 as Senate Bill 25-003, takes effect on August 1, 2026 and makes it a crime to sell, purchase, manufacture, or transfer most semiautomatic rifles and shotguns with detachable magazines, along with gas-operated semiautomatic handguns with detachable magazines.¹ The law does not ban possession of firearms already owned before that date, but it does close the in-state secondary market for covered guns and layers a new permit requirement on top of every firearm purchase in Colorado.

What the Law Prohibits

Starting August 1, 2026, it becomes illegal to knowingly manufacture, distribute, transfer, sell, or purchase any firearm the statute defines as a “specified semiautomatic firearm.”¹ The prohibition runs the full chain of commerce, from factory production to private sales between neighbors. One narrow exception survives on the transfer side: you can still transfer a covered firearm to someone who lives in another state, or to a federally licensed firearms dealer.

The penalties are criminal. A first violation is a class 2 misdemeanor. A second or subsequent violation becomes a class 6 felony, which carries potential prison time and a felony record.¹ A felony conviction also triggers 18 U.S.C. § 922(g), the federal statute that bars anyone convicted of a felony from possessing any firearm at all.² So a second offense in Colorado effectively ends your ability to own guns anywhere.

Which Firearms Are Covered

The law defines a “specified semiautomatic firearm” in three categories:

Semiautomatic rifles with a detachable magazine
Semiautomatic shotguns with a detachable magazine
Gas-operated semiautomatic handguns with a detachable magazine

The detachable magazine is the trigger for all three. A semiautomatic rifle with a fixed internal magazine falls outside the definition. The handgun category is narrower than it first looks because it reaches only gas-operated designs, leaving blowback-operated pistols out. The statute also carves out certain firearm types and specific models from the definition; the full exclusion list appears in the bill text.¹

This approach targets the mechanical platform rather than a list of model names or a features test looking at pistol grips, folding stocks, or barrel shrouds. If the gun is semiautomatic and takes a detachable magazine, and it’s not on the exclusion list, it’s covered.

If You Already Own One

SB 25-003 does not require you to surrender or register a firearm you already own. Possession of a covered firearm acquired before August 1, 2026 remains legal.¹ What changes is what you can do with it. After the effective date, you cannot sell it, give it away, or otherwise transfer it to another Colorado resident. The only lawful transfers left are to an out-of-state buyer or to a federally licensed dealer.

The practical effect is that the in-state resale market for these firearms closes on August 1, 2026. Owners who want to move a covered gun will need to find a buyer outside Colorado or go through a licensed dealer for the transfer.

The Permit-to-Purchase Requirement

SB 25-003 reaches well beyond the semiautomatic ban. It also requires anyone buying any firearm in Colorado to first obtain a firearms safety course eligibility card. Getting that card means completing an in-person safety course (either four or twelve hours, with the longer option spread across two days), submitting fingerprints, and passing a criminal background check.¹

Even after you finish the course and clear the background check, the county sheriff has final approval authority. The sheriff can deny the permit based on a “reasonable belief” that the applicant poses a danger, and can revoke a previously issued permit under the same standard. Permits must be renewed every five years. This requirement applies to every firearm purchase, not just purchases of semiautomatic firearms.

Magazines and Rapid-Fire Devices

Colorado has restricted magazines holding more than fifteen rounds since July 1, 2013.³ SB 25-003 leaves the fifteen-round cap in place but raises the penalty for violating it from a class 2 misdemeanor to a class 1 misdemeanor, which carries heavier jail time and fines.¹

The law also defines “rapid-fire device” and classifies those devices as dangerous weapons under Colorado law. This matters because the U.S. Supreme Court struck down the federal bump stock ban in June 2024, holding in Garland v. Cargill that the ATF exceeded its authority by classifying bump stocks as machine guns.⁴ Colorado’s state classification now covers ground the federal rule no longer does.

Court Challenges That Could Change This

The law’s future depends in part on what the U.S. Supreme Court does with pending Second Amendment cases. In 2022, New York State Rifle & Pistol Association v. Bruen held that firearms regulations must be consistent with the nation’s historical tradition of firearm regulation, and lower courts have since split on whether that standard allows bans on commonly owned semiautomatic platforms.

As of early 2026, several cases challenging semiautomatic weapons bans and large-capacity magazine restrictions are pending before the Supreme Court, including petitions in Viramontes, National Association for Gun Rights, Duncan, and Gator’s Custom Guns.⁵ A ruling on whether semiautomatic rifles with detachable magazines qualify as arms in “common use” under the Second Amendment could reshape the legal ground under SB 25-003. If the Court holds those firearms are constitutionally protected, Colorado’s ban is vulnerable. If the Court declines the cases or rules the other way, the ban stands. In the meantime, the August 1, 2026 effective date arrives regardless.

1
Colorado General Assembly. SB25-003 Semiautomatic Firearms and Rapid-Fire Devices
2
United States Sentencing Commission. Section 922(g) Firearms
3
Colorado Bureau of Investigation. Colorado Revised Statutes 18-12-302
4
Supreme Court of the United States. Garland v Cargill, No 22-976
5
Duke Center for Firearms Law. SCOTUS Gun Watch