Machine Guns & Conversion Devices in Montana

Last updated December 31, 2023 .

Montana does not criminalize mere possession of a machine gun. It is legal to possess a machine gun in Montana:

For a scientific purpose;
If the machine gun is not usable as a weapon and is possessed as a curiosity, ornament, or keepsake; or
For a purpose manifestly not aggressive or offensive.¹

However, possession or use of a machine gun for an offensive or aggressive purpose is a crime punishable by imprisonment in the state penitentiary for a term of not less than 10 years.² Moreover, possession or use of a machine gun in the perpetration or attempted perpetration of a crime of violence is a crime punishable by imprisonment in the state penitentiary for a term of not less than 20 years.³

Possession or use of a machine gun is presumed to be for an offensive or aggressive purpose when the machine gun is used or possessed by a person who has been convicted of a crime of violence⁴ in any court of record, state or federal, in the U.S. or its territories.⁵

Federal law requires machine guns to be registered with the Bureau of Alcohol, Tobacco, Firearms & Explosives (ATF), and generally prohibits the transfer or possession of machine guns manufactured after May 19, 1986.⁶

See our Machine Guns & Automatic Firearms policy summary for a comprehensive discussion of this issue.

Notes

Mont. Code Ann § 45-8-307(2) and (3).
Mont. Code Ann. § 45-8-304.
Mont. Code Ann. § 45-8-303.
Mont. Code Ann. § 45-8-302 defines a “crime of violence” to include any of the following offenses or an attempt to commit any of the following offenses: forcible felony, robbery, burglary, and criminal trespass.
Mont. Code Ann. § 45-8-305.
18 U.S.C. § 922(o); 26 U.S.C. § 5861(d).