Colorado Revised Statute § 18-12-102 makes it a crime to possess certain weapons classified as “dangerous” or “illegal.” You “possess” a weapon by carrying it or by having it under your control, such as in your car, home, storage facility, etc.

The following graphic illustrates what these dangerous and illegal weapons may look like:

Below our Colorado criminal defense lawyers provide full descriptions of what constitutes dangerous or illegal weapons as well as potential defenses to criminal charges.

• 1. Dangerous Weapons
• 2. Illegal Weapons
• 3. Defenses
• Additional Reading

1. Dangerous Weapons

The following are Colorado’s official definitions of “dangerous weapons,” which you may not knowingly possess in the state:

• Firearm silencer: Any instrument, attachment, weapon, or appliance for causing the firing of any gun, revolver, pistol, or other firearm to be silent or intended to lessen or muffle the noise of the firing of any such weapon.
• Machine gun: Any firearm, whatever its size and usual designation, that shoots automatically more than one shot, without manual reloading, by a single function of the trigger.
• Machine gun conversion device: Any part designed or intended, or combination of parts designed or intended, for use in converting a firearm into a machine gun. A common example is bump stocks.
  
• Short rifle: A rifle having a barrel less than 16 inches long or an overall length of fewer than 26 inches.
• Short shotgun: A shotgun having a barrel or barrels less than 18 inches long or an overall length of fewer than 26 inches. This includes shotguns of normal length that have been sawed-off so that the barrel is less than 18 inches.¹

A weapon does not need to be operable in order to be “dangerous.” You violate 18-12-102 C.R.S. if the weapon can be made operable with the addition of a readily replaceable part or quick repair.²

As discussed above, knowingly possessing a dangerous weapon is a class 5 felony carrying one to three years in Colorado State Prison and/or $1,000 to $100,000.³

2. Illegal Weapons

The following are Colorado’s official definitions of “illegal weapons,” which you may not knowingly possess in the state:

• Ballistic knife: Any knife that has a blade that is forcefully projected from the handle by means of a spring-loaded device or explosive charge.
• Blackjack: Any billy, sand club, sandbag, or other hand-operated striking weapon consisting, at the striking end, of an encased piece of lead or other heavy substance and, at the handle end, a strap or springy shaft which increases the force of impact.
• Gas gun: A device designed for projecting gas-filled projectiles that release their contents after having been projected from the device and includes projectiles designed for use in such a device.
• Metallic knuckles: A metal weapon worn over the knuckles intended to increase the injuries caused when hitting someone. They are also called brass knuckles. (This description is from Merriam Webster since the C.R.S. does not provide an official definition.)

As discussed above, knowingly possessing an illegal weapon in Colorado is a class 1 misdemeanor carrying six to 18 months in jail and/or $500 to $5,000.⁴

3. Defenses

Here at Colorado Legal Defense Group, we have represented literally thousands of people charged with weapons crimes, such as knowingly possessing a dangerous or illegal weapon. In our experience, the following five defenses have proven very effective with prosecutors, judges, and juries.

1. You had no idea the weapon was in your possession. For example, perhaps someone left it in your home without your knowledge.
2. The weapon was not operable and could not easily be made so. An irrevocably broken weapon is not illegal to possess.
3. The weapon was found during an illegal search and seizure. If the court agrees to suppress the weapon as evidence because of the police’s misconduct, the state may be left with too weak of a case to prosecute.
4. You were a peace officer or member of the armed forces of the United States or Colorado National Guard acting in the lawful discharge of your duties. A note from your superior is often enough to get the D.A. to drop the charges.
5. You held a valid permit and license for the possession of the weapon. For example, you had a federal tax stamp from the AFT.

Note that it is not a defense that you did not know that the weapon was illegal to possess.⁵

Additional Reading

• The Deadly Weapon Doctrine: Common Law Origin – Harvard Law Review.
• The Law as to Concealed Deadly Weapons – Kentucky Law Journal.
• Dangerous, Not Deadly: Possession of a Firearm Distinguished from Use under the Felony-Murder Rule – William Mitchell Law Review.
• Premeditation Inferred from Use of Deadly Weapon – Kentucky Law Journal.
• Deadly Weapons in the Hands of Police Officers, on Duty and off Duty – Journal of Urban Law.

See our related article, Illegal Weapons in Colorado – 10 that you cannot have.

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