Are Submachine Guns Legal or Illegal in Colorado?

You can lawfully own a submachine gun (SMG) in Colorado if

1. you lawfully obtain an “NFA tax stamp” from the ATF (Bureau of Alcohol, Tobacco, Firearms and Explosives), and
2. the SMG was manufactured and lawfully registered prior to May 19, 1986.

To obtain an NFA tax stamp, you must pay $200 and complete and have approved an ATF Form 4, Application for Tax Paid Transfer and Registration of Firearm, for the specific SMG. This process can take several months.¹

In this article, I discuss what you need to know about the legality of submachine guns (SMGs) in Colorado law. 

“Submachine Gun” Meaning

Abbreviated SMG, submachine guns are portable automatic firearms that discharge from the hip or shoulder and that use handgun-type ammunition. Machine guns tend to be larger and have more firepower than submachine guns because machine guns use rifle ammunition.

SMGs were initially developed for WWI. The military still uses them. The most famous SMG model is the Thompson submachine gun, nicknamed the Tommy Gun.²

Prohibited Possession

You may not possess or own a submachine gun – or any other firearm – in Colorado if you are:

• a convicted felon;
• convicted of any crime carrying more than one year in prison;
• convicted of attempting to commit a felony;
• convicted of a misdemeanor crime of domestic violence;
• subject to a restraining order that prohibits gun possession;
• a fugitive from justice;
• an unlawful user of controlled substances or a drug addict;
• adjudicated a “mental defective” or have been committed to any mental institution;
• an undocumented alien;
• in the U.S. on a non-immigrant visa;
• dishonorably discharged from the Armed Forces; or
• a former U.S. citizen after renouncing your citizenship.³

Penalties

In Colorado, possessing a “dangerous weapon” (which includes submachine guns) without a valid NFA tax stamp is a class 5 felony. The punishment is:

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

But a subsequent violation of possessing a dangerous weapon without a valid NFA tax stamp is a class 4 felony in Colorado. The penalty increases to:

• 2 to 6 years in prison (with 3 years mandatory parole), and/or
• $2,000 to $500,000 in fines.⁴

Note that it is a class 5 felony in Colorado for people to possess firearms (including submachine guns) if they have a prior conviction for domestic violence or a qualifying felony crime. Penalties for POWPO (Possession of Weapon by a Previous Offender) include:

• 1 to 3 years in prison (with two years of mandatory parole), and/or
• $1,000 to $100,000 in fines.⁵

Weapons Requiring an NFA Stamp

In Colorado, you must obtain a valid NFA stamp in order to lawfully possess:

1. A machine gun;
2. A submachine gun;
3. A silencer (suppressor);
4. A shotgun with a barrel(s) of less than 18 inches long;
5. A rifle having a barrel(s) of less than 16 inches long;
6. A weapon made from a shotgun if such weapon as modified has an overall length of less than 26 inches or a barrel(s) of less than 18 inches long;
7. A weapon made from a rifle if such weapon as modified has an overall length of less than 26 inches or a barrel(s) of less than 16 inches long;
8. Any other weapon, as defined in 26 U.S.C. 5845 subsection (e); and
9. A destructive device.⁶

Frequently Asked Questions

What is the difference between a machine gun and a submachine gun?

A machine gun is any firearm that fires more than one round with a single pull of the trigger. A submachine gun is a type of machine gun that typically fires pistol-caliber ammunition, such as 9mm or .45 ACP. Because most submachine guns fire automatically, they are generally regulated as machine guns under both Colorado and federal law.

Are Glock switches legal in Colorado?

No. A Glock switch, auto sear, or other machine-gun conversion device is generally illegal to possess under Colorado and federal law. These devices can convert a semi-automatic firearm into a machine gun, and possession of an unregistered conversion device can lead to serious felony charges.

Can I inherit a submachine gun in Colorado?

Possibly. Federal law allows certain machine guns to be transferred to heirs if the firearm is lawfully registered and all federal transfer requirements are satisfied. The heir generally must complete paperwork with the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) before taking possession of the firearm.

Can I take a registered submachine gun across state lines?

Usually only with advance federal approval. Owners of registered machine guns generally must obtain permission from the ATF before transporting the firearm into another state. In addition, the destination state’s laws must allow possession of the firearm.

Can a gun trust own a submachine gun?

Yes. Federal law allows certain NFA firearms, including transferable machine guns, to be owned through a properly created gun trust. A trust can make it easier for multiple authorized trustees to lawfully possess and use the firearm, though all federal registration and transfer requirements still apply.

Are AR-15 rifles considered machine guns?

Generally no. Most AR-15 rifles sold to civilians are semi-automatic firearms that fire only one round per trigger pull. However, an AR-15 that has been modified to fire automatically may be classified as a machine gun under federal and Colorado law.

Can I shoot a registered submachine gun at a Colorado gun range?

Usually yes. A person who lawfully owns a federally registered transferable machine gun may generally use it at a shooting range that permits automatic firearms. Range rules vary, so it is important to confirm that the facility allows machine guns before bringing one. 

Is every firearm made before May 19, 1986 legal to own in Colorado?

No. The key issue is not simply when the firearm was manufactured. To be lawfully possessed by most civilians, a machine gun generally must be a federally registered transferable machine gun that was lawfully registered before the federal 1986 cutoff. Some firearms manufactured before that date cannot be transferred to civilians because of federal registration restrictions.

What happens if I possess a machine gun that is not properly registered?

Possessing an unregistered machine gun can result in both state and federal criminal charges. Depending on the circumstances, a conviction may carry substantial fines, imprisonment, and the permanent loss of firearm rights.

Can a convicted felon legally own a submachine gun in Colorado?

Generally no. Federal law prohibits most convicted felons from possessing firearms, including machine guns and submachine guns. Colorado law may also prohibit firearm possession by certain people with qualifying criminal convictions.

Additional Resources

For more information, refer to the following:

• Giffords Law Center to Prevent Gun Violence – A nonprofit advocating for stricter gun laws.
• Gun Control Act of 1968 – A federal law regulating firearm sales and ownership.
• 1994 Assault Weapons Ban – A federal law prohibiting certain semi-automatic firearms.
• National Rifle Association – A lobbying group promoting gun rights.
• Gun Owners for Responsible Ownership – An advocacy group supporting balanced gun regulations.

Legal References