Colorado sorts prohibited weapons into two statutory buckets, and which bucket a weapon falls into decides whether you face a felony or a misdemeanor. Illegal weapons in Colorado, in the narrow statutory sense, are blackjacks, gas guns, ballistic knives, and metallic knuckles, and possessing any of them is a class 1 misdemeanor.1Justia. Colorado Code 18-12-102 – Possessing a Dangerous or Illegal Weapon The heavier category, “dangerous weapons,” covers machine guns, short-barreled shotguns and rifles, machine gun conversion devices, and firearm silencers, and possession is a class 5 felony. Layered on top are separate rules for large-capacity magazines, concealed carry, explosives, and who can lawfully possess a firearm at all.
Dangerous Weapons: The Felony Category
Under C.R.S. 18-12-102, “dangerous weapons” are firearm silencers, machine guns, machine gun conversion devices, short shotguns, and short rifles. Possession is a class 5 felony, punishable by one to three years in prison and a fine between $1,000 and $100,000. A second or subsequent conviction moves the charge to a class 4 felony, which carries two to six years in prison and fines up to $500,000.1Justia. Colorado Code 18-12-102 – Possessing a Dangerous or Illegal Weapon
Under federal law, a short-barreled shotgun has a barrel under 18 inches and a short-barreled rifle has a barrel under 16 inches.2Bureau of Alcohol, Tobacco, Firearms and Explosives. National Firearms Act A machine gun conversion device — the small part that turns a semi-automatic firearm into an automatic — is treated the same as the machine gun itself.
There is one affirmative defense. If you are a peace officer or a member of the armed forces acting in the lawful discharge of your duties, or if you hold a valid permit and license for the weapon, you can raise that at trial.1Justia. Colorado Code 18-12-102 – Possessing a Dangerous or Illegal Weapon An affirmative defense means you admit the possession and carry the burden of proving it was lawful. For silencers and short-barreled firearms, the “valid permit” is federal NFA registration.
Illegal Weapons: The Misdemeanor Category
The statute’s shorter list, “illegal weapons,” consists of blackjacks, gas guns, ballistic knives, and metallic knuckles. Possession is a class 1 misdemeanor, carrying up to 364 days in jail and a fine of up to $1,000.1Justia. Colorado Code 18-12-102 – Possessing a Dangerous or Illegal Weapon The same peace-officer, military-duty, and valid-permit affirmative defense applies.
Ballistic knives, which launch a detachable blade, stay in this category even though Colorado repealed its switchblade and gravity knife ban in 2017.
Large-Capacity Magazines
Since July 1, 2013, Colorado has prohibited selling, transferring, or possessing a magazine capable of accepting more than 15 rounds. For shotguns, the limit is length-based: a fixed tubular shotgun magazine cannot exceed 28 inches (including extensions), and a detachable shotgun magazine cannot hold more than eight shells when combined with a fixed magazine.3Justia. Colorado Code 18-12-301 – Definitions A violation is a class 2 misdemeanor, punishable by up to 120 days in jail and a fine of up to $750.4Justia. Colorado Code 18-12-302 – Large-Capacity Magazines Prohibited – Penalties – Exceptions
The law grandfathers magazines owned before July 1, 2013, so long as the owner has kept continuous possession.4Justia. Colorado Code 18-12-302 – Large-Capacity Magazines Prohibited – Penalties – Exceptions Proving that date is the practical problem, since magazines don’t come stamped with a purchase date. A few categories are exempt outright: magazines permanently altered to hold no more than 15 rounds, tubular devices designed exclusively for .22 caliber rimfire ammunition, and tubular magazines in lever-action firearms.3Justia. Colorado Code 18-12-301 – Definitions
Knives: State Law vs. Local Ordinances
Colorado repealed its ban on switchblades and gravity knives effective August 9, 2017. Both are now legal to own under state law, though they remain subject to the concealed carry blade-length limit of 3.5 inches.5Knife Rights. Colorado Switchblade Ban Repeal Effective August 9th Ballistic knives are the exception and remain illegal under 18-12-102.
Here is the catch. Colorado does not preempt local knife ordinances, so several major cities, including Denver, Aurora, Boulder, Colorado Springs, and Lakewood, still ban switchblades under their own municipal codes.5Knife Rights. Colorado Switchblade Ban Repeal Effective August 9th Legal statewide does not mean legal in every city. Check the local code before carrying.
Explosives and Incendiary Devices
Possessing or controlling an explosive or incendiary device is a class 5 felony, and manufacturing, mailing, or distributing one is a class 4 felony, carrying two to six years in prison.6Justia. Colorado Code 18-12-109 – Possession, Use, or Removal of Explosives or Incendiary Devices Even possessing component parts intended for building an explosive device is a separate felony.7Colorado Bureau of Investigation. Colorado Code 18-12-109 – Possession, Use, or Removal of Explosives or Incendiary Devices
Exemptions cover peace officers acting in their official capacity, armed forces members, authorized mine employees, permit holders, and businesses authorized to use chemical or biological materials in their lawful operations.7Colorado Bureau of Investigation. Colorado Code 18-12-109 – Possession, Use, or Removal of Explosives or Incendiary Devices
Concealed Carry
Carrying a concealed knife or firearm without authorization is a class 1 misdemeanor.8Justia. Colorado Code 18-12-105 – Unlawfully Carrying a Concealed Weapon – Unlawful Possession of Weapons “Concealed” means placed out of sight so it would not be apparent on ordinary observation. Several exemptions apply:
- Carrying on property you own or control, including your home or business.
- Carrying a weapon in a private vehicle for lawful protection of yourself or others while traveling.
- Holding a valid Colorado concealed handgun permit, which covers handguns specifically.
- Peace officers carrying in conformance with agency policy.
The concealed handgun permit is issued by your county sheriff after a background check and fingerprinting, with $52.50 paid to the Colorado Bureau of Investigation plus whatever administrative fee your sheriff’s office charges.9Colorado Bureau of Investigation. Concealed Handgun Permit (CHP) The permit is for handguns only. Carrying explosives, incendiary devices, or other dangerous items in the state legislature buildings or hearing rooms is separately prohibited regardless of any permit.8Justia. Colorado Code 18-12-105 – Unlawfully Carrying a Concealed Weapon – Unlawful Possession of Weapons
Prohibited Use of Weapons
C.R.S. 18-12-106 makes it a class 1 misdemeanor to knowingly aim a firearm at another person, recklessly discharge a firearm or bow, set a loaded trap and leave it unattended, or possess a firearm while under the influence of alcohol or a controlled substance. A concealed carry permit is explicitly not a defense to the intoxication charge.10FindLaw. Colorado Code 18-12-106 – Prohibited Use of Weapons
Throwing stars and nunchaku have their own rule. Aiming or throwing them at someone, or possessing them in public outside of an authorized demonstration or organized class, is a class 2 misdemeanor. When transporting them for a demonstration or class, they must be in a closed, non-accessible container.10FindLaw. Colorado Code 18-12-106 – Prohibited Use of Weapons
Who Cannot Possess a Weapon at All
Colorado’s Previous-Offender Rule
If you have been convicted of a felony, or an attempt or conspiracy to commit a felony, under Colorado, another state’s, or federal law, possessing any firearm or weapon covered by Colorado’s weapons laws is a separate crime. The baseline is a class 5 felony, one to three years in prison. If you used or threatened to use the weapon while committing another crime, probation and alternative sentences are off the table and the sentence goes to the Department of Corrections. Any sentence for this offense runs consecutively with a sentence you are already serving, so the time stacks. Juvenile adjudications for acts that would be felonies also count, subject to a ten-year window after completion of sentence and a petition process for relief.11Justia. Colorado Code 18-12-108 – Possession of Weapons by Previous Offenders
Federally Prohibited Persons
Federal law under 18 U.S.C. § 922(g) bars several categories of people from possessing any firearm or ammunition:
- Anyone convicted of a crime punishable by more than one year in prison.
- Fugitives from justice.
- Unlawful users of controlled substances.
- People adjudicated as mentally defective or committed to a mental institution.
- Certain noncitizens, including those illegally in the United States or admitted on most nonimmigrant visas.
- Dishonorably discharged veterans.
- People who have renounced U.S. citizenship.
- Subjects of qualifying domestic restraining orders.
- Anyone convicted of a misdemeanor crime of domestic violence, under the Lautenberg Amendment.
These federal prohibitions apply in Colorado regardless of state law, and a single act of possession can be prosecuted in both systems.
Extreme Risk Protection Orders
Since January 1, 2020, family members, household members, or law enforcement can petition a court for an Extreme Risk Protection Order when someone poses a significant risk to themselves or others by having access to firearms.13Colorado Bureau of Investigation. Colorado Code 13-14.5-103 – Temporary Extreme Risk Protection Orders A full ERPO lasts 364 days and requires the respondent to surrender all firearms and any concealed carry permit to law enforcement or a federally licensed firearms dealer.14Colorado General Assembly. HB19-1177 Extreme Risk Protection Orders Firearms that were lawful to own become unlawful to hold while the order is in force. If the order expires without extension or is terminated, the firearms are returned.
Straw Purchases
Buying a firearm for someone else, especially someone legally prohibited from owning one, is a federal crime under 18 U.S.C. § 932. The maximum penalty is 15 years in federal prison and a $250,000 fine. If the firearm is later used to commit a felony, an act of terrorism, or a drug trafficking crime, the maximum jumps to 25 years.15Bureau of Alcohol, Tobacco, Firearms and Explosives. Don’t Lie for the Other Guy Firearms trafficking under § 933, which covers knowingly transferring a firearm to a prohibited person or moving guns across state lines for illegal purposes, carries up to 15 years, with enhancements if the firearm is used in a violent crime or drug offense.
If You Are Charged
Weapons cases in Colorado sit on top of federal firearms law, and both systems have their own definitions, penalty structures, and defenses. An attorney can look at whether the search that produced the weapon was lawful, whether the prosecution can prove knowing possession, and whether an affirmative defense under 18-12-102 applies. Federal sentencing operates on different math than Colorado’s presumptive ranges, so if federal charges are in play, experience in both court systems matters.