In Montana, you have to be at least 18 to buy a rifle or shotgun from a licensed dealer and at least 21 to buy a handgun from a licensed dealer. Those are the federal minimums, and Montana does not add its own purchase-age rules on top of them, so the federal thresholds are the ones that apply at every gun store in the state.
Buying From a Licensed Dealer
Federal law sets two ages depending on what you’re buying. A licensed dealer cannot sell or deliver a handgun to anyone under 21, and cannot sell a rifle or shotgun to anyone under 18. Because Montana has not enacted its own purchase ages, a Montana dealer applies those same cutoffs whether you walk into a shop in Billings, Bozeman, or anywhere else in the state.
Every purchase from a licensed dealer also runs through the National Instant Criminal Background Check System. The dealer submits your information and the system returns proceed, denied, or delayed.1Federal Bureau of Investigation. Firearms Checks (NICS) A delayed result means the FBI needs more time. Under the Brady Act, if the FBI cannot reach a determination within three business days the dealer may complete the transfer, though the dealer is not required to.2Federal Bureau of Investigation. About NICS A delay is not a denial, and most resolve with an approval.
NFA Items
For items regulated under the National Firearms Act, including short-barreled rifles, short-barreled shotguns, and suppressors, you must be at least 21 to purchase from a dealer. As of January 2026, the federal tax stamp for individual NFA transfers dropped to $0, but the registration paperwork (Form 4) is still required before you can legally possess the item.
Buying From a Private Seller
Private sales follow a different set of ages. Federal law prohibits transferring a handgun to anyone under 18 in a private transaction, and there is no federal minimum age for buying a long gun from a private seller. Montana has not set its own minimum age for private long gun sales either, so a private rifle or shotgun sale to a minor is not blocked by a specific state age rule.
Montana also does not require background checks for private firearm sales. If two private individuals complete a transaction without involving a licensed dealer, no check is legally mandated. The federal and state rules on who can and cannot possess a firearm still apply, and a private seller who knowingly transfers a firearm to a prohibited person commits a federal crime. Many private sellers voluntarily route a sale through a licensed dealer to run a background check; dealers typically charge between $20 and $75 for that service.
Possessing a Firearm as a Minor
Buying and possessing are two different questions, and Montana’s rules on possession reflect the state’s hunting culture.
Federal law draws one hard line: no one under 18 may possess a handgun, with narrow exceptions for employment, ranching, farming, target practice, and hunting, each requiring prior written parental consent.3Office of the Law Revision Counsel. 18 U.S. Code 922 – Unlawful Acts
Montana adds a rule for the youngest kids. A parent, guardian, or custodian cannot allow a child under 14 to carry or use a firearm in public unless the child is accompanied by a responsible adult or is under the supervision of a qualified firearms safety instructor.4Montana State Legislature. Montana Code 45-8-344 – Use of Firearms by Children Under 14 Years of Age Prohibited – Exceptions For teenagers 14 and older, Montana does not impose a state-level restriction on possessing long guns. A 15-year-old can legally carry a rifle while hunting without special documentation beyond what the federal handgun rules require.
So the practical picture for minors in Montana: a child of any age can use a rifle or shotgun for hunting and shooting sports under adult supervision, teens 14 and older face no additional state-level restrictions on long gun possession, and handgun possession stays off-limits for anyone under 18 outside the narrow federal exceptions.
Who Cannot Buy or Possess at Any Age
Meeting the age cutoff is only the first filter. Federal law bars several categories of people from possessing any firearm or ammunition regardless of age: anyone convicted of a crime punishable by more than a year in prison, anyone subject to a qualifying domestic protective order, anyone convicted of a misdemeanor crime of domestic violence, fugitives, unlawful users of controlled substances, anyone dishonorably discharged from the military, anyone who has renounced U.S. citizenship, and anyone adjudicated as mentally defective or involuntarily committed to a mental institution.5Bureau of Alcohol, Tobacco, Firearms and Explosives. Identify Prohibited Persons
Montana adds a narrower state prohibition. Under state law, a person convicted of certain qualifying felonies, specifically those that triggered an enhanced sentence or that require registration as a sexual or violent offender, cannot purchase or possess a firearm. The penalty is two to ten years in state prison.6Montana State Legislature. Montana Code 45-8-313 – Unlawful Possession of Firearm by Convicted Person The federal prohibition reaches more people than Montana’s state law does, because federal law covers all felonies punishable by more than a year while Montana’s statute targets a subset of felons.
Domestic Violence
The federal domestic violence prohibition catches more buyers than almost any other restriction. Under the Lautenberg Amendment, even a misdemeanor domestic violence conviction triggers a lifetime ban on possessing firearms. The conviction does not have to be recent. Offenses predating the law’s 1996 effective date still count. The qualifying offense must involve the use or attempted use of physical force, or the threatened use of a deadly weapon, against a spouse, former spouse, co-parent, cohabitant, or someone in a similar relationship.7United States Department of Justice Archives. Restrictions on the Possession of Firearms by Individuals Convicted of a Misdemeanor Crime of Domestic Violence A person subject to a qualifying domestic protective order is also federally prohibited for as long as the order remains in effect.5Bureau of Alcohol, Tobacco, Firearms and Explosives. Identify Prohibited Persons
Penalties for Selling to an Underage Buyer
Selling or transferring a firearm to someone you know is a prohibited person, whether because of age, criminal history, or any other disqualifying factor, is a federal crime. Under federal law, it is illegal for any person to sell, deliver, or otherwise transfer a handgun to someone they know or have reasonable cause to believe is under 18.3Office of the Law Revision Counsel. 18 U.S. Code 922 – Unlawful Acts Licensed dealers face the stricter cutoffs described above: no handgun to a buyer under 21 and no long gun to a buyer under 18.
Straw purchases carry particularly steep penalties. A straw purchase happens when someone buys a firearm on behalf of another person who is prohibited from buying one or wants to avoid the background check. The Bipartisan Safer Communities Act created dedicated federal straw purchase offenses carrying up to 15 years in prison and a $250,000 fine. If the firearm is later used in a felony, an act of terrorism, or drug trafficking, the sentence can reach 25 years.8Bureau of Alcohol, Tobacco, Firearms and Explosives. Don’t Lie for the Other Guy An adult who buys a handgun because a 19-year-old friend cannot is squarely within that definition.
On the state side, Montana holds parents and guardians accountable for allowing children under 14 to use firearms in public without proper supervision.4Montana State Legislature. Montana Code 45-8-344 – Use of Firearms by Children Under 14 Years of Age Prohibited – Exceptions