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Illegal Weapons in Colorado – 10 That You Cannot Have

Colorado law prohibits the knowing possession of the following 10 weapons (with some exceptions): 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.
Graphic that shows defenses to having illegal weapons in Colorado, such as lack of awareness, illegal police search, or the weapon was inoperable

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? Graphic that shows the various illegal and dangerous weapons that are prohibited 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
Home security 12 gauge short barrel semi- auto firearm/ shotgun resting on a wooden plank floor with four bullets.
Short-barreled shotguns are illegal in Colorado (unless you have an NFA stamp).

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
Machine gun positioned on a gun mount against barren background outside
Machine guns are illegal in Colorado unless you have an NFA tax stamp.

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
Man's fist wearing brass knuckles (which is illegal in Colorado) against a black background
Metal knuckles are illegal weapons in Colorado.

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

For more in-depth information, refer to the following scholarly articles:

Legal References

  1. Colorado Revised Statute 18-12-101. C.R.S. 18-12-102. 26 U.S.C. 5812, 5822 & 5845. HB 23-1293. See also People v. Tenorio, (1979), 590 P.2d 952.
  2. See note 1.
  3. See note 1. See, for example, People v. Licona-Ortega (Colo.App. 2022) 511 P.3d 721.
  4. See note 1.
  5. CRS 18-12-101. CRS 18-12-102.
  6. See note 1. See also Miller v. District Court In and For Nineteenth Judicial Dist., (1977), 566 P.2d 1063, 193 Colo. 404.
  7. CRS 18-12-109. 26 U.S.C. 5812, 5822 & 5845
  8. CRS 18-12-101. CRS 18-12-102. Senate Bill 8 (2017).
  9. See note 5.
  10. See note 5.

About the Author

Picture of Michael Becker

Michael Becker

Michael Becker has over a quarter-century's worth of experience as an attorney and more than 100 trials under his belt. He is a sought-after legal commentator and is licensed to practice law in Colorado, Nevada, California, and Florida.

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