Colorado’s New Gun Laws: Semiauto Ban, Age 21, and Waiting Period

Colorado’s new gun laws, passed in a wave of legislation from 2023 through 2025, change who can buy a firearm, how long they must wait, where they can carry, how firearms must be stored, and, starting August 1, 2026, which semiautomatic firearms can be sold in the state at all. Penalties range from $25 civil fines to felony charges. Several of the laws have already been challenged in court, and at least one spent more than a year blocked by an injunction before taking effect.

Ban on Specified Semiautomatic Firearms Starting August 1, 2026

Senate Bill 25-003 is the most sweeping of the recent changes. Beginning August 1, 2026, it is illegal to manufacture, sell, transfer, or purchase a specified semiautomatic firearm in Colorado. If you already own one before that date, you can keep it, but you cannot sell or transfer it to another person inside the state. The only transfers allowed are to someone living in another state or to a federally licensed dealer.¹

A first violation is a Class 2 misdemeanor. A second or subsequent offense is a Class 6 felony.

The same bill reclassifies rapid-fire devices as dangerous weapons and raises the penalty for selling, transferring, or possessing a large-capacity magazine (more than 15 rounds) to a Class 1 misdemeanor, with up to 364 days in jail and up to a $1,000 fine.¹ Colorado capped magazine capacity at 15 rounds back in 2013, but the penalty under the old framework was weaker.

Minimum Age of 21 to Buy Any Firearm

Senate Bill 23-169 raised the minimum age to purchase any firearm in Colorado to 21. Before this law, 18-year-olds could buy rifles and shotguns; federal law already set the handgun threshold at 21.²

A federal district court blocked the law with an injunction on the day it was set to take effect in August 2023. The injunction held for more than a year. On November 5, 2024, the Tenth Circuit Court of Appeals reversed the district court and ordered the injunction dissolved, clearing the way for enforcement.³ If you are under 21, you cannot legally purchase any firearm in Colorado, rifles and shotguns included. Further proceedings on remand could still affect how the law is enforced.

Three-Day Waiting Period on Every Transfer

House Bill 23-1219 requires a waiting period before any firearm can change hands. The clock runs three days from when a background check is initiated, or until the check comes back approved, whichever is later. It applies to every seller in the state, licensed dealers and private individuals alike.⁴

Delivering a firearm before the waiting period expires is a civil infraction. A first offense carries a fine of up to $500. A second or subsequent offense raises the fine to between $500 and $5,000.⁴

Exceptions are limited. Antique firearms and curios or relics are exempt. A service member being deployed outside the United States within 30 days may transfer a firearm to a family member without waiting.⁴

Background Checks on Private Sales

Colorado has required background checks on private firearm transfers since 2013. If you are not a licensed dealer and you sell or give a firearm to someone, you must arrange for a licensed dealer to run the background check first. The dealer runs the check, records the transaction, and retains the paperwork. The dealer may charge up to $10 for the service, on top of the CBI’s $15 InstaCheck fee.⁵

A background check approval is valid for 30 calendar days. If the transfer does not happen within that window, you need a new check. The three-day waiting period applies on top of the background check, so a private sale involves both the check and the wait.

Serialization of Ghost Guns

Senate Bill 23-279 bans the manufacture, sale, transfer, and possession of firearms and firearm components without a serial number. The law covers both completed unserialized firearms and unfinished frames or receivers that can be readily assembled into a working firearm.⁶

Anyone who owned an unserialized firearm, frame, or receiver before the law took effect had until January 1, 2024, to have a federally licensed dealer engrave a serial number on it. Missing that deadline makes the item illegal to possess. A first violation is a Class 1 misdemeanor, with up to 364 days in jail and up to a $1,000 fine. A second or subsequent offense is a Class 5 felony.⁶

The engraving process itself requires a background check to confirm the owner is legally eligible to possess a firearm. Someone who might not pass that check faces a bind: bringing the item in for engraving could trigger a denial, and keeping it is already illegal.

Where You Cannot Carry a Firearm

Senate Bill 24-131 created a statewide list of places where carrying a firearm, openly or concealed, is prohibited:

State legislative buildings, local government buildings where elected officials work, and courthouses
Licensed child care centers, all public and private K-12 schools, and colleges and universities
Polling places, central count facilities, and the area within 100 feet of a ballot drop box while election activity is in progress
Public parks as defined under Colorado law

The prohibition extends to adjacent parking areas for government buildings. Concealed carry permit holders get a narrow exception: they may carry a concealed handgun in the parking areas of child care centers and higher education institutions, though not inside the buildings themselves.⁷

Violating the restriction is a Class 1 misdemeanor, with up to 364 days in jail and up to a $1,000 fine. For permit holders, a conviction triggers automatic revocation of the permit by the issuing sheriff.⁸

Local rules complicate the picture in both directions. A local government can pass an ordinance permitting firearms in its own buildings, opting out of the state ban.⁷ Because Colorado repealed its firearms preemption law in 2021, cities and counties can also impose their own restrictions on top of state law. Check both state and local rules for anywhere you plan to carry.

Federal property is a separate regime. Under 18 U.S.C. § 930, carrying a firearm into a federal building where employees regularly work is a federal offense punishable by up to one year in prison. Post offices, federal courthouses, and Social Security offices all count. Federal court facilities specifically carry up to two years.⁹

Concealed Carry Permit Training

House Bill 24-1174, effective July 1, 2025, overhauled training requirements for concealed handgun permits. Applicants must now complete an in-person class of at least eight hours covering safe handling, storage, shooting fundamentals, relevant state and federal law, use of deadly force, and interaction with law enforcement during an emergency. The class must include a live-fire exercise and a written competency exam, and applicants must pass both.¹⁰

Training must be completed within one year before submitting the application. A current peace officer certification satisfies the competency requirement. The law also bars issuance of a permit to anyone convicted of certain misdemeanor offenses within the five years before applying.¹⁰

Who Can File a Red Flag Petition

Colorado’s extreme risk protection order law, in place since 2019, lets a court temporarily remove firearms from someone who poses a danger to themselves or others. Senate Bill 23-170 expanded who can file. In addition to family or household members and law enforcement, licensed medical providers, licensed mental health professionals, licensed educators, and district attorneys can now petition the court directly.¹¹

The process is civil, not criminal. No conviction is required. A petitioner presents evidence under oath that the person poses a significant risk. If the judge finds the evidence sufficient, a temporary order requires immediate surrender of all firearms, with a full hearing to follow where the respondent can contest it.

Safe Storage at Home

Firearms must be stored securely when not in use to keep them away from unsupervised minors and from anyone in the household who is legally prohibited from possessing a firearm. A firearm counts as safely stored if it is kept in a locked gun safe or secure container, has a locking device installed, or is a personalized firearm with its safety features activated. The key, combination, or unlocking mechanism must be kept away from anyone who should not have access.

Failing to store a firearm responsibly is a misdemeanor if you know or should know that a minor could access it without parental permission, or that someone in the home is barred from possessing firearms. Separate child access prevention provisions make it a felony to intentionally or recklessly provide a handgun to anyone under 18.

Reporting a Lost or Stolen Firearm

If you have reason to believe one of your firearms has been lost or stolen, you must report it to a law enforcement agency within five days of discovering the loss. The report should include a description of the firearm, including manufacturer, model, serial number, caliber, and other identifying marks to the extent you know them.¹²

A first failure to report is a civil infraction with a $25 fine. A second or subsequent offense is an unclassified misdemeanor punishable by up to $500. A household member can file the report on the owner’s behalf, which satisfies the owner’s obligation. Licensed dealers are exempt from this statute because federal rules through the ATF already require them to report theft or loss within 48 hours.¹³

1
Colorado General Assembly. SB25-003 Semiautomatic Firearms and Rapid-Fire Devices
2
Colorado General Assembly. SB23-169 Increasing Minimum Age to Purchase Firearms
3
United States Court of Appeals for the Tenth Circuit. Rocky Mountain Gun Owners v. Polis, No. 23-1251
4
Colorado General Assembly. HB23-1219 Waiting Period to Deliver a Firearm
5
InstaCheck – Colorado. InstaCheck
6
Colorado General Assembly. SB23-279 Unserialized Firearms and Firearm Components
7
Colorado General Assembly. SB24-131 Prohibiting Carrying Firearms in Sensitive Spaces
8
Colorado General Assembly. Senate Bill 24-131 – Prohibit Carrying Firearms in Sensitive Spaces
9
Office of the Law Revision Counsel. 18 U.S. Code 930 – Possession of Firearms and Dangerous Weapons in Federal Facilities
10
Colorado General Assembly. HB24-1174 Concealed Carry Permits and Training
11
Colorado General Assembly. SB23-170 Extreme Risk Protection Order Petitions
12
Justia Law. Colorado Revised Statutes Title 18 Section 18-12-113 – Failure to Report a Lost or Stolen Firearm – Exception
13
Bureau of Alcohol, Tobacco, Firearms and Explosives. Report Firearms Theft or Loss