State SBR law

Are short-barreled rifles legal in Montana? (2026)

By Cole Harlan, EditorUpdated Oct 28, 2026How we verifyEditorial standards

Montana has no law that uses the term short-barreled rifle. Its sawed-off firearm offense, MCA 45-8-340, covers a rifle that was made with a longer barrel and then cut down. The law exempts a person with a valid federal tax stamp. How that exemption applies after ATF's October 9, 2026 change is not yet verified.

Not legal advice. This page summarizes Montana statutes and federal guidance as of the date above. Local rules and your own circumstances can matter. Check with your dealer or a Montana attorney if you're unsure.

The short answer

One state offense: possession of a sawed-off firearm under MCA 45-8-340. It reaches a rifle or shotgun that was modified to a shorter length than it had when originally manufactured.
Federal tax stamp exemption: subsection (3)(f) exempts a person with a valid federal tax stamp for the firearm.
Penalty: a first conviction is a fine of $200 to $500, 5 days to 6 months in county jail, or both. Priors raise it to up to 5 years in state prison.
Repeal is planned: per our suppressor guide, three legislators announced bills for the 2027 session to repeal the sawed-off firearm section. Nothing changes until a bill passes and takes effect.

The statute

The section is MCA 45-8-340, titled Sawed-off firearm, penalty. We found no provision in the sections we read that names a short-barreled rifle. Subsection (1) says:

(1) "A person commits the offense of possession of a sawed-off firearm if the person knowingly possesses a rifle or shotgun that when originally manufactured had a barrel length of:"

(1)(a) "16 inches or more and an overall length of 26 inches or more in the case of a rifle; or"

(1)(c) "the firearm has been modified in a manner so that the barrel length, overall length, or both, are less than specified in subsection (1)(a) or (1)(b)."

(2) "The barrel length is the distance from the muzzle to the rear-most point of the chamber."

(3)(f) "by a person who has a valid federal tax stamp for the firearm, issued by the bureau of alcohol, tobacco, firearms and explosives;"

The other exemptions in subsection (3) cover peace officers, federal officers, national guard members, people called to aid them, firearms kept for educational or scientific purposes that can't be fired, and certain pre-1900 muzzleloading collector guns. We found no separate exception for dealers or manufacturers in this section.

The section covers a gun modified from a longer original configuration. It doesn't address making a new short-barreled gun.

How Montana defines an SBR

The Montana statutes we read have no SBR definition. Section 45-8-340 describes a modified rifle by its original lengths of 16 inches (barrel) and 26 inches (overall). Federal law (26 U.S.C. 5845) uses the same 16-inch barrel and 26-inch overall lines for a rifle. See 26 U.S.C. 5845.

Penalty

Subsection (4) sets the penalty for a first conviction:

"A person convicted of the offense of possession of a sawed-off firearm shall be fined not less than $200 or more than $500 or be imprisoned in the county jail for not less than 5 days or more than 6 months, or both, upon a first conviction."

With prior convictions, the same subsection says:

"If a person has one or more prior convictions under this section or one or more prior felony convictions under a law of this state, another state, or the United States, the person shall be fined an amount not to exceed $1,000 or be imprisoned in the state prison for a term not to exceed 5 years, or both."

Is legality tied to federal registration?

Yes, through the exemption in subsection (3)(f), which refers to a valid federal tax stamp issued by ATF. The text doesn't say what happens to a gun that was never stamped because ATF stopped enforcing approval and registration.

ATF's October 9, 2026 open letter says it stopped enforcing Form 1 and Form 4 approval and registration for SBRs, SBSs, suppressors and AOWs. Voluntary forms are still processed. How a court would read the tax stamp wording for a gun without one: untested, and Not yet verified.

The Montana Attorney General's August 27, 2026 letter to prosecutors, sheriffs and police chiefs, as described in our suppressor guide, said criminal investigations under MCA 45-8-340 (along with 45-8-336 and 45-8-337) "may be tenuous given the current legal environment." It asked city and county attorneys to send cases under those statutes to the Montana Department of Justice Prosecution Services Bureau "for review and advisement before any charges". That is a request for central review, not a promise that no one will be charged.

The letter came before ATF's October 9 guidance. We haven't verified any Attorney General statement written after it. Our Montana suppressor guide covers how the state's registration-based provisions play out and the 2027 bills.

Hunting

SBR-specific hunting rules: Not yet verified. Per our suppressor guide, Montana has allowed hunting with a suppressor since 2015, but only one registered with ATF, which the Attorney General reads as NFA registration.

Other laws that interact

Concealed carry: MCA 45-8-316 punishes carrying a firearm concealed on your person with a fine up to $500, up to 6 months in county jail, or both. Subsection (3) says the section does not apply to a person eligible to possess a firearm under state or federal law. Whether a short rifle is ever carried that way: Not yet verified.
Local rules: MCA 45-8-310 states that "the legislature withholds from local governments the power to restrict or regulate the possession of firearms."
Machine guns: MCA 45-8-302 defines a machine gun as a firearm designed to discharge more than one shot by a single function of the trigger. That is a separate category from the sawed-off firearm section.
Shotguns: the same section 45-8-340 covers shotguns modified from an original barrel of 18 inches or more.
Minors, manufacturing and CLEO sign-off: Not yet verified.

Braced pistols

The state statutes cited here don't mention pistol braces. See our pistol brace guide for the federal side.

Federal process in 2026

The making and transfer tax on SBRs has been $0 since January 1, 2026.
ATF stopped Form 1 and Form 4 enforcement on October 9. Voluntary forms are still processed. See NFA wait times.
Dealers use a Form 4473 and NICS check. ATF won't enforce 18 U.S.C. 922(b)(4) "Until final rules are issued."
"For now," interstate transport still needs an approved Form 20 (18 U.S.C. 922(a)(4)).
A dealer can't sell where state law forbids it (18 U.S.C. 922(b)(2)).

ATF says there is no automatic grandfathering if enforcement resumes. Full detail is on our SBR rules 2026 page, and you can compare states with the state NFA checker.

Checked against the official statute text on October 28, 2026.

Frequently asked questions

Are short-barreled rifles legal in Montana?

Montana has no statute that names a short-barreled rifle. MCA 45-8-340 makes it an offense to knowingly possess a rifle that was originally made with a barrel of 16 inches or more and an overall length of 26 inches or more and was later modified shorter. Subsection (3)(f) exempts a person with a valid federal tax stamp for the firearm.

What is the penalty for a sawed-off rifle in Montana?

A first conviction brings a fine of $200 to $500, 5 days to 6 months in county jail, or both. With prior convictions under the section or prior felony convictions, the fine can be up to $1,000 and prison up to 5 years, or both.

Does Montana require a federal tax stamp for an SBR?

Subsection (3)(f) of MCA 45-8-340 exempts a person who has a valid federal tax stamp for the firearm. How it applies to a gun without a stamp after ATF's October 9, 2026 change is untested and not yet verified.

Is Montana changing its sawed-off firearm law?

Per our suppressor guide, three legislators announced bills for the 2027 session to repeal the sawed-off firearm section. Nothing changes until a bill passes and takes effect.

Do I need a Form 20 to bring an SBR into or out of Montana?

According to ATF's fact sheet, "For now," transporting an SBR across state lines still requires an approved Form 20.

Are short-barreled rifles legal in Montana? (2026)

The short answer

The statute

How Montana defines an SBR

Penalty

Is legality tied to federal registration?

Hunting

Other laws that interact

Braced pistols

Federal process in 2026

Frequently asked questions

Sources

Keep exploring

Are short-barreled rifles legal in Montana? (2026)

The short answer

The statute

How Montana defines an SBR

Penalty

Is legality tied to federal registration?

Hunting

Other laws that interact

Braced pistols

Federal process in 2026

Frequently asked questions

Sources

Keep exploring

The Gun Release Report