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. 

1. Mont. Code Ann § 45-8-307(2) and (3).[↩]
2. Mont. Code Ann. § 45-8-304.[↩]
3. Mont. Code Ann. § 45-8-303.[↩]
4. 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.[↩]
5. Mont. Code Ann. § 45-8-305.[↩]
6. 18 U.S.C. § 922(o); 26 U.S.C. § 5861(d).[↩]