The Colorado magazine ban makes it a crime to sell, transfer, or possess any ammunition magazine that holds more than 15 rounds. The rule has been in force since July 1, 2013, under C.R.S. § 18-12-302, and a violation is a class 2 misdemeanor carrying up to 120 days in jail and a fine of up to $750.1Justia. Colorado Code 18-12-302 – Large-Capacity Magazines Prohibited – Penalties – Exceptions2Justia. Colorado Code 18-1.3-501 – Misdemeanors Classified – Penalties Narrow exemptions exist for people who already owned a covered magazine before the effective date, for on-duty law enforcement and military personnel, and for certain manufacturers and dealers.
What Counts as a Large-Capacity Magazine
C.R.S. § 18-12-301 defines a large-capacity magazine as any fixed or detachable magazine, box, drum, feed strip, or similar device that can accept more than 15 rounds. A device designed to be readily converted to hold more than 15 rounds also qualifies, even if it ships from the factory at a lower capacity.3Justia. Colorado Code 18-12-301 – Definitions
Shotguns get their own thresholds. A fixed tubular shotgun magazine is restricted if it holds more than 28 inches of shells, extension included. A nontubular detachable shotgun magazine is restricted if it can accept more than eight shells when combined with a fixed magazine.3Justia. Colorado Code 18-12-301 – Definitions
Three categories of devices are carved out of the definition entirely:
- A magazine permanently modified so it cannot hold more than 15 rounds.
- An attached tubular magazine designed to accept and operate only with .22 caliber rimfire ammunition.
- A tubular magazine housed inside a lever-action firearm.
The last two exclusions matter for classic sporting rifles that use tubular magazines with capacities technically above 15 rounds.3Justia. Colorado Code 18-12-301 – Definitions
What the Law Prohibits
Selling, transferring, or possessing a large-capacity magazine anywhere in Colorado is illegal. “Transfer” covers any change in custody or ownership, so giving one away or lending one to a friend at a range breaks the statute the same way a retail sale would.1Justia. Colorado Code 18-12-302 – Large-Capacity Magazines Prohibited – Penalties – Exceptions
Possession alone is enough. You do not have to use the magazine in a crime or take it out of your home. Simply keeping one in your collection triggers liability unless an exemption applies, and bringing a restricted magazine into Colorado from another state is treated the same as possessing one here.
Who Can Legally Have One
The Grandfather Clause
The most useful exemption is for people who owned a large-capacity magazine on July 1, 2013. If you owned the magazine that day and have maintained continuous possession of it since, you can keep it.1Justia. Colorado Code 18-12-302 – Large-Capacity Magazines Prohibited – Penalties – Exceptions
A few points trip people up. The exemption protects only the original owner. Sell, give, or lend a grandfathered magazine to someone else and that person has no legal right to possess it, and you cannot restore the exemption by taking it back. The statute requires “continuous possession” but does not define the phrase. Storing the magazine in a safe at your home almost certainly qualifies; the law leaves gray areas around extended absences and shared-household situations.
If you claim the grandfather exemption and the state disagrees, the prosecution carries the burden of proving you did not own the magazine before the cutoff.1Justia. Colorado Code 18-12-302 – Large-Capacity Magazines Prohibited – Penalties – Exceptions Few magazines carry any proof of purchase date, so a dated receipt or photograph is worth keeping.
People moving to Colorado from another state do not qualify. The statute requires ownership “on July 1, 2013,” not just ownership before arriving in Colorado. Relocating here with magazines that exceed 15 rounds means possessing restricted items with no applicable exemption.
Duty, Dealer, and Manufacturer Exemptions
The statute also carves out a handful of groups:
- Employees of any branch of the U.S. armed forces, while carrying a firearm in the course of official duties.
- Employees of any federal, state, or local law enforcement agency, including agencies from other states, when bearing a firearm in the course of official duties.
- Colorado-based manufacturers and licensed gun dealers, but only to make, possess, or sell large-capacity magazines for transfer to the military, government agencies, out-of-state retailers, approved foreign governments, or individual buyers in states where possession is legal.
- A person transporting a large-capacity magazine to an out-of-state buyer on behalf of a Colorado manufacturer, for that purpose only.
The law enforcement and military exemptions are duty-specific, not personal. An off-duty officer who wants a large-capacity magazine for private use has to rely on the grandfather clause or one of the manufacturer channels rather than the duty exemption.1Justia. Colorado Code 18-12-302 – Large-Capacity Magazines Prohibited – Penalties – Exceptions
Retired officers sometimes assume the federal Law Enforcement Officers Safety Act (LEOSA) shields them from state magazine restrictions. It does not. LEOSA lets qualified retired officers carry concealed firearms across state lines, but the statute says nothing about magazine capacity. A retired officer carrying a large-capacity magazine in Colorado faces the same restrictions as any other civilian.
Penalties for a Violation
A violation is a class 2 misdemeanor.1Justia. Colorado Code 18-12-302 – Large-Capacity Magazines Prohibited – Penalties – Exceptions Colorado overhauled its misdemeanor sentencing structure in 2022, so the exposure depends on when the conduct occurred:
- Offenses on or after March 1, 2022: up to 120 days in jail, a fine of up to $750, or both.
- Offenses before March 1, 2022: three months to 364 days in jail, a fine of $250 to $1,000, or both.
Many online guides still quote the pre-2022 numbers.2Justia. Colorado Code 18-1.3-501 – Misdemeanors Classified – Penalties
Each magazine is a separate act of possession, so owning several restricted magazines can produce stacked charges. Courts treat the 15-round threshold as a bright line and look to the technical evidence of a magazine’s capacity.
Local Limits Can Be Stricter
State law sets the floor, not the ceiling. Some Colorado municipalities have adopted magazine restrictions tighter than 15 rounds. Boulder County, for example, defines a large-capacity magazine as one holding more than 10 rounds, five fewer than the state threshold. If you move between jurisdictions inside Colorado, you can be compliant in one county and in violation in the next. Check local ordinances before assuming the state number is the only one that applies to you.
Traveling Through Colorado With Magazines
If you are driving through Colorado with large-capacity magazines that are legal at both origin and destination, federal law offers limited help. The Firearm Owners Protection Act (FOPA) allows you to transport firearms and ammunition through restrictive states, provided the gun is unloaded and neither the firearm nor the ammunition is readily accessible from the passenger compartment.4Office of the Law Revision Counsel. 18 USC 926A – Interstate Transportation of Firearms
FOPA’s text protects “a firearm” and “ammunition” during interstate transport but does not mention magazines as a separate category. Whether a large-capacity magazine qualifies as part of the firearm or as ammunition under FOPA is unsettled. Relying on FOPA as a defense after a Colorado stop is a gamble. Shipping magazines separately to your destination is the safer route.
Where the Ban Stands in Court
The Colorado Supreme Court unanimously upheld the law in 2020. The picture grew more complicated after the U.S. Supreme Court’s 2022 decision in New York State Rifle & Pistol Association v. Bruen, which requires gun regulations to be consistent with the nation’s historical tradition of firearms regulation.
In March 2026, the D.C. Court of Appeals struck down the District of Columbia’s 10-round magazine limit in Benson v. United States, holding that magazines of all capacities are “arms in common and ubiquitous use by law-abiding citizens” and therefore protected by the Second Amendment.5D.C. Courts. Benson v. United States, No. 23-CF-0514 That ruling conflicts with every federal circuit court that has addressed the issue post-Bruen. The First, Second, Fourth, Seventh, and Ninth Circuits have all upheld magazine capacity bans. Colorado sits in the Tenth Circuit, which has not yet issued a definitive ruling. In May 2026, the U.S. Department of Justice filed a new federal lawsuit in Denver’s U.S. District Court challenging Colorado’s 15-round limit under the Second Amendment. That case is still in its early stages.
The ban remains fully enforceable. Rulings striking down similar laws elsewhere do not create a defense to prosecution in Colorado. Until the Supreme Court resolves the circuit split, the 15-round limit is the law you have to live with.