Illegal Weapons in Colorado – 10 That You Cannot Have

Colorado law prohibits the knowing possession of the following 10 weapons (with some exceptions):

• 1. Machine Guns
• 2. Submachine Guns (SMGs)
• 3. Short Shotguns
• 4. Short Rifles
• 5. Gas Guns
• 6. Firearm Silencers
• 7. Destructive Devices
• 8. Ballistic Knives
• 9. Blackjacks
• 10. Metallic Knuckles

In this article I discuss each of these illegal or dangerous weapons as well as the penalties for knowingly possessing them in Colorado. You “possess” a weapon in one of three ways:

1. Actual possession, which is physically holding or carrying the weapon; or
2. Constructive possession, which is having control over the weapon such as by keeping it in a drawer or storage unit; or
3. Joint possession, which is sharing possession with one or more other people.

1. Machine Guns

Machine guns shoot more than one shot automatically by a single trigger pull and without manual reloading.

Colorado state law classifies machine guns as “dangerous weapons”. Possessing a dangerous weapon is a class 5 felony, punishable by:

• 1 to 3 years in Colorado State Prison (with 2 years of mandatory parole) and/or
• $1,000 to $100,000 in fines.

A subsequent conviction of unlawful possession of a dangerous weapon is a class 4 felony, punishable by:

• 2 to 6 years in prison (with 3 years mandatory parole) and/or
• $2,000 to $500,000 in fines.

However, you can legally own a machine gun as long as you obtain an NFA tax stamp for the machine gun from the ATF (Bureau of Alcohol, Tobacco, Firearms and Explosives).¹

2. Submachine Guns (SMGs)

Submachine guns are like machine guns, except they use handgun ammo instead of rifle ammo.

As a “dangerous weapon” under Colorado law, submachine guns cannot be lawfully possessed. To do so is a class 5 felony, carrying:

• 1 to 3 years in prison (with 2 years of mandatory parole) and/or
• $1,000 to $100,000 in fines.

A subsequent conviction is a class 4 felony, punishable by:

• 2 to 6 years in prison (with 3 years mandatory parole) and/or
• $2,000 to $500,000 in fines.

However, you can legally own a submachine gun as long as you obtain an NFA tax stamp for the SMG from the ATF.²

See our related article, Are submachine guns legal in Colorado?

3. Short Shotguns

Short shotguns are shotguns with a barrel(s) less than 18 inches long or an overall length of less than 26 inches.

Short shotguns guns are “dangerous weapons” in Colorado. Possessing one is a class 5 felony, carrying:

• 1 to 3 years in prison (with 2 years of mandatory parole) and/or
• $1,000 to $100,000 in fines.

A subsequent conviction is a class 4 felony, punishable by:

• 2 to 6 years in prison (with 3 years mandatory parole) and/or
• $2,000 to $500,000 in fines.

However, you can legally own a short shotgun as long as you obtain an NFA tax stamp for the short shotgun from the ATF.³

4. Short Rifles

Short rifles are rifles with a barrel(s) less than 16 inches long or an overall length of less than 26 inches.

Since Colorado gun law classifies short rifles as “dangerous weapons,” possessing one is a class 5 felony, carrying:

• 1 to 3 years in prison (with 2 years of mandatory parole) and/or
• $1,000 to $100,000 in fines.

A subsequent conviction is a class 4 felony, punishable by:

• 2 to 6 years in prison (with 3 years mandatory parole) and/or
• $2,000 to $500,000 in fines.

However, you can legally own a short rifle as long as you obtain an NFA tax stamp for the short rifle from the ATF.⁴

5. Gas Guns

Gas guns shoot projectiles by compressed air.

Colorado weapons law classifies gas guns as “illegal weapons.” This means possession is charged as a class 1 misdemeanor, carrying:

• 6 to 18 months in jail and/or
• $500 to $5,000 in fines.⁵

6. Firearm Silencers

Like they sound, firearm silencers muffle the noise that guns make.

Because silencers are classified as “dangerous weapons” in Colorado, possessing one is a class 5 felony, carrying:

• 1 to 3 years in prison (with 2 years of mandatory parole) and/or
• $1,000 to $100,000 in fines.

A subsequent conviction is a class 4 felony, punishable by:

• 2 to 6 years in prison (with 3 years mandatory parole) and/or
• $2,000 to $500,000 in fines.

However, you can legally own a silencer as long as you obtain an NFA tax stamp for the silencer from the ATF.⁶

7. Destructive Devices

Colorado law makes it a felony to possess a bomb or other explosive or incendiary device. The specific penalties turn on the kind of device it is and your intentions.

In general, however, you may lawfully possess a “destructive device” as long as you obtain an NFA tax stamp for the device from the ATF.⁷

8. Ballistic Knives

Ballistic knives have blades that are forcefully projected from the handle through a spring-loaded device or explosive charge.

Ballistic knives are “dangerous weapons” under Colorado law. Therefore, possessing one is a class 5 felony, carrying:

• 1 to 3 years in prison (with 2 years of mandatory parole) and/or
• $1,000 to $100,000 in fines.

A subsequent conviction is a class 4 felony, punishable by:

• 2 to 6 years in prison (with 3 years mandatory parole) and/or
• $2,000 to $500,000 in fines.

Note that it is no longer a crime in Colorado to possess a switchblade knife or gravity knife.⁸

9. Blackjacks

Blackjacks comprise billies, sand clubs, sandbags, or other hand-operated striking weapons 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.

With blackjacks being “illegal weapons” in Colorado, possession is prosecuted as a class 1 misdemeanor, carrying:

• 6 to 18 months in jail and/or
• $500 to $5,000 in fines.⁹

10. Metallic Knuckles

Metal knuckles – also called “brass knuckles” – are metal guards worn over your knuckles to increase the force of a punch.

In Colorado, metal knuckles are considered “illegal weapons.” This means possessing them is a class 1 misdemeanor, carrying:

• 6 to 18 months in jail and/or
• $500 to $5,000 in fines.¹⁰

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.

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Legal References