Colorado’s new gun laws, passed in a wave of legislation since 2023, reshape almost every part of owning a firearm in the state: who can buy one, how long they have to wait, where they can carry it, how it must be stored, and, starting August 1, 2026, which semiautomatic firearms can be sold at all. Some rules are already in force. Others take effect on future dates. A few have been tied up in court. Here is what has changed and what it means if you own, buy, sell, or carry a firearm in Colorado.
The 2026 Ban on Specified Semiautomatic Firearms
Senate Bill 25-003 is the most sweeping firearms law Colorado has passed. Beginning August 1, 2026, it becomes illegal to manufacture, sell, transfer, or purchase a specified semiautomatic firearm in the state.1Colorado General Assembly. SB25-003 Semiautomatic Firearms and Rapid-Fire Devices
If you already own one of these firearms before that date, you can keep it. What you cannot do is sell or give it to another person inside Colorado. The only permitted transfers are to someone who lives in another state or to a federally licensed dealer.
A first violation is a Class 2 misdemeanor. A second or subsequent offense becomes a Class 6 felony. The same law 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, punishable by up to 364 days in jail and up to $1,000 in fines.1Colorado General Assembly. SB25-003 Semiautomatic Firearms and Rapid-Fire Devices Colorado’s 15-round magazine cap has existed since 2013, but the new penalty structure puts real weight behind it.
Three-Day Waiting Period on Every Transfer
House Bill 23-1219 requires a waiting period before any firearm can be delivered to a buyer. The clock runs for three days after a background check is initiated, or until the check comes back approved, whichever is later. Every seller is covered: licensed dealers and private individuals alike.2Colorado General Assembly. HB23-1219 Waiting Period to Deliver a Firearm
Handing over a firearm before the waiting period ends is a civil infraction. A first offense carries a fine of up to $500. A second or later offense carries $500 to $5,000.
A few narrow exceptions apply. Antique firearms and items classified as curios or relics are not subject to the wait. A service member being deployed outside the United States within 30 days may transfer a firearm to a family member without waiting. Also worth knowing: the Colorado Bureau of Investigation charges a $15 fee for each background check run through its InstaCheck system, effective March 1, 2025.3InstaCheck – Colorado. InstaCheck
Age 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 21 as the floor for handguns.4Colorado General Assembly. SB23-169 Increasing Minimum Age to Purchase Firearms
The law had a rough start. A federal district court enjoined it on the day it was set to take effect in August 2023, and the injunction held for over a year. Then, on November 5, 2024, the Tenth Circuit reversed that ruling and ordered the injunction dissolved.5United States Court of Appeals for the Tenth Circuit. Rocky Mountain Gun Owners v. Polis, No. 23-1251 The age-21 requirement is now enforceable across all firearm types. Further proceedings on remand could still affect implementation, so buyers under 21 should confirm the current status before attempting a purchase.
Ghost Guns and Serialization
Senate Bill 23-279 bans the manufacture, sale, transfer, and possession of firearms and firearm components that lack a serial number. That covers finished unserialized firearms as well as unfinished frames or receivers that could be readily assembled into a working gun.6Colorado General Assembly. SB23-279 Unserialized Firearms and Firearm Components
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. That deadline has passed. Possessing an unserialized item now is a Class 1 misdemeanor for a first offense (up to 364 days in jail, up to $1,000 in fines) and a Class 5 felony for any subsequent offense (one to three years in prison, up to $100,000 in fines).7Justia Law. Colorado Revised Statutes Title 18 Section 18-1.3-401 – Felonies Classified – Presumptive Penalties
Serialization requires a background check to confirm the owner can legally possess a firearm. Anyone who might not pass faces a bind: bringing the gun in for engraving could trigger a denial, but keeping it unserialized is a crime too.
Where You Cannot Carry
Senate Bill 24-131 created a statewide list of sensitive spaces where firearms are prohibited, whether openly carried or concealed:
- 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 areas within 100 feet of a ballot drop box while election activity is in progress
- Public parks as defined under Colorado law
Adjacent parking areas are also off-limits at government buildings. Concealed carry permit holders get one narrow allowance: they may keep a concealed handgun in the parking areas of child care centers and higher education institutions, though not inside the buildings.8Colorado General Assembly. SB24-131 Prohibiting Carrying Firearms in Sensitive Spaces
A violation is a Class 1 misdemeanor, up to 364 days in jail and up to $1,000 in fines. For permit holders, a conviction also triggers automatic revocation of the concealed carry permit by the issuing sheriff.9Colorado General Assembly. Senate Bill 24-131 – Prohibit Carrying Firearms in Sensitive Spaces
Local law can shift the picture in either direction. SB 24-131 lets a local government pass an ordinance permitting firearms in its own building, opting out of the state ban for its own facility. Separately, Colorado repealed its firearms preemption law in 2021, which means cities and counties can also enact restrictions stricter than the state baseline. Check both state law and any local ordinance where you plan to carry.
Federal property is a separate matter. Under 18 U.S.C. § 930, carrying a firearm into any building owned or leased by the federal government where federal employees regularly work is a federal offense punishable by up to one year in prison, and up to two years for a federal court facility. That reach includes post offices, federal courthouses, and Social Security offices.10Office of the Law Revision Counsel. 18 U.S. Code 930 – Possession of Firearms and Dangerous Weapons in Federal Facilities
Concealed Carry Permit Training
House Bill 24-1174, effective July 1, 2025, rewrote the training requirement for concealed handgun permits. Applicants must complete an in-person class of at least eight hours covering safe handling, storage, shooting fundamentals, state and federal law, use of deadly force, and how to interact with law enforcement in an emergency. The class must include a live-fire exercise and a written competency exam, and the applicant must pass both.11Colorado General Assembly. HB24-1174 Concealed Carry Permits and Training
Training must be completed within one year before you apply. Current certification as a peace officer 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. Since an SB 24-131 conviction triggers automatic revocation, the stakes of carrying in a prohibited spot now go well past the fine.
Expanded Red Flag Petitioners
Colorado’s extreme risk protection order law has been on the books since 2019, allowing family members and law enforcement to ask a court to temporarily remove firearms from someone who poses a danger. Senate Bill 23-170 expanded who can file. Licensed medical providers, licensed mental health professionals, licensed educators, and district attorneys can now petition directly.12Colorado General Assembly. SB23-170 Extreme Risk Protection Order Petitions
The process remains civil. No conviction is required. The petitioner presents evidence under oath that the person poses a significant risk of injury to themselves or others. If a judge agrees, a temporary order requires immediate surrender of all firearms, followed by a full hearing where the person whose firearms were removed can contest the order.
Storage, Lost or Stolen, and Private Sales
Colorado law requires firearms to be stored securely when not in use, to keep them out of the hands of unsupervised minors and anyone in the household 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 or combination must be kept away from anyone who should not have access. Failing to store a firearm responsibly on property you own or control is a misdemeanor if you know or should know that a minor could reach it without a parent’s permission, or that a resident is legally barred from possessing firearms. Separate child access prevention provisions make it a felony to intentionally or recklessly provide a handgun to anyone under 18.
If you have reason to believe a firearm has been lost or stolen, Colorado requires you to report it to a law enforcement agency within five days of discovering the loss. The report should include the manufacturer, model, serial number, caliber, and any other identifying marks you know.13Justia Law. Colorado Revised Statutes Title 18 Section 18-12-113 – Failure to Report a Lost or Stolen Firearm – Exception A first failure to report is a civil infraction with a $25 fine; a second or later offense is an unclassified misdemeanor punishable by up to $500. A household member can file on the owner’s behalf. Licensed dealers are exempt from this statute because they follow stricter federal reporting to the ATF, with a 48-hour window.14Bureau of Alcohol, Tobacco, Firearms and Explosives. Report Firearms Theft or Loss Even with low state fines, reporting matters: if a stolen firearm is used in a crime and you never reported it missing, you may face civil claims arguing your negligence contributed to the harm.
Private sales require a background check that has been in place since 2013. If you sell or give a firearm to another person and you are not a licensed dealer, you must have a licensed dealer run the background check before the transfer. The dealer follows the same procedures as a retail sale and may charge up to $10 for the service, on top of the $15 CBI InstaCheck fee.3InstaCheck – Colorado. InstaCheck A background check approval is valid for 30 calendar days; miss that window and a new check is required. Transferring a firearm without going through this process can create civil liability if the recipient later uses it to cause harm. The three-day waiting period stacks on top: private sales require both the check and the wait.