This article has been updated.

The Feb. 14 mass shooting that left 17 dead at Marjory Stoneman Douglas High School in Parkland, Fla., has once again prompted calls from gun-control advocates for stricter laws in Minnesota and across the country, while gun-rights activists are pushing back.

Because any conversation about what the laws should be must begin with what's already on the books, here is an overview of Minnesota's gun laws.

Who can buy a gun in Minnesota?

Age restrictions: Federal law prohibits federally licensed dealers from selling or transferring a rifle or shotgun (these are also referred to as long guns) to anyone under the age of 18, but it does not set a minimum age for private sales. Under Minnesota law, the minimum age to purchase a rifle or shotgun without the permission of a parent or guardian is 18 in a municipality (defined as a county, town, city, school district or other municipal corporation or political subdivision) and 14 outside a municipality.

More on minors and firearms here.

Individuals must be 21 or older to purchase a handgun or handgun ammunition from a federally licensed dealer. The minimum age to buy a semiautomatic military-style assault weapon from a dealer is 18.

NOTE: These are the minimum ages at which individuals can legally purchase firearms in Minnesota in at least some circumstances, such as in private sales, which are less regulated than those by federally licensed dealers. Additional requirements, such as permits, background checks or firearms safety certification, may also apply.

Permit requirements: Under the law, no permit is required to purchase or transfer most long guns, such as rifles or shotguns. To purchase a long gun from a federally licensed dealer, the purchaser must undergo a background check through the FBI's National Instant Criminal Background Check System (NICS).

Those who wish to buy a handgun or a semiautomatic military-style assault weapon from a federally licensed dealer must possess a permit to carry or obtain a permit to purchase. This can be done by submitting an application for a one-year permit to the local police department or sheriff's office, which will then perform a series of background checks to ensure the buyer is eligible and either grant or deny the permit within seven days.

Some federally licensed gun dealers allow one-time buyers to apply directly at the gun shop where they will purchase a handgun. The dealer will conduct a name and date-of-birth background check using the NICS to determine the buyer's eligibility under state and federal law. In these cases, the dealer may not transfer the weapon for five business days after the sale or transfer is reported to law enforcement, unless the police department or sheriff's office waives all or a portion of the seven-day waiting period in writing if there is a threat to the life of the transferee or member of their household.

Private sales: Sales and transfers of any type of gun by a seller who is not a federally licensed dealer, which may take place at a gun show, online or elsewhere, are not subject to the requirements that law enforcement conduct a background check on the buyer or that the buyer obtain a permit to purchase. This is known as the "gun show (or private seller) loophole." If a person who is legally prohibited from purchasing a firearm buys one from a private seller, the purchase is illegal, but the sale is not. However, if the buyer (or transferee) uses a handgun or semiautomatic assault rifle within one year while committing a felony violent crime, the seller could be held criminally liable in some circumstances.

It is a crime in Minnesota to knowingly sell a firearm to an ineligible person or to make a "straw purchase," where an eligible person purchases a firearm with the intent of providing it to an ineligible person.

Violent criminals: Under state and federal law, individuals who have been convicted of violent crimes or any felony are prohibited from possessing a gun. In some cases, eligibility to possess a firearm may be restored along with other civil rights once the punishment is completed. Federal law prevents anyone convicted of a misdemeanor crime of domestic violence from possessing a firearm. Individuals who are subject to restraining orders from intimate partners or children or who are unlawful users of controlled substances are also prohibited from possessing guns.

Minnesota law also prohibits anyone who has been convicted of a "crime of violence" from possessing firearms. There are also restrictions for some individuals convicted of drug crimes.

Mental health restrictions: Under federal law, any person who has been ruled by a judge to be incompetent to stand trial, found not guilty by reason of insanity or mental defect or who has been involuntarily "committed to any mental institution" is prohibited from purchasing or possessing a firearm. However, the federal government does not require states to report such individuals to NICS.

Minnesota prohibits anyone from purchasing or possessing a firearm who: has ever been committed to a mental health facility for being mentally ill, developmentally disabled, or dangerous; has ever been found incompetent to stand trial or not guilty by reason of mental illness; is or has ever been in treatment for chemical dependence, unless treatment has been completed.

Minnesota law requires courts to report to NICS within three business days when individuals are committed to mental health facilities for being mentally ill, developmentally disabled, dangerous or chemically dependent; are judged to be incompetent to stand trial or not guilty by reason of mental illness; or have their rights to possess a firearm restored under state law.

The full statute detailing who is ineligible to possess firearms can be found here.

Are minors allowed to possess guns in Minnesota?

In a municipality (defined as county, town, city, school district or other municipal corporation or political subdivision), it is illegal to provide a firearm, airgun or ammunition to a minor under the age of 18 without the permission of a parent, guardian or local police department.

In general, the minimum age to possess a handgun, handgun ammunition or semiautomatic military-style assault rifle without the supervision of a parent or guardian is 18. But there are some notable exceptions.

Outside of a municipality, children 14 years of age or older may handle or use a firearm, airgun or ammunition with the supervision of a parent or guardian.

A person under the age of 16 may possess a firearm without the supervision of a parent or guardian if: they are on land owned or occupied by the person or their parent or guardian; are participating in an organized target shooting program with adult supervision; are participating in a firearms safety program or traveling to or from class; or are age 14 or 15 and possess a firearms safety certificate.

Can undocumented immigrants possess guns?

No.

What's the difference between semiautomatic and fully automatic weapons?

Semiautomatic refers to a firearm in which one cartridge is fired and a new cartridge is reloaded each time the trigger is pulled. A fully automatic weapon fires continuously while the trigger is pulled. Fully automatic weapons, or "machine guns," as they are sometimes referred to in statutes, are banned in most circumstances under federal law. More on fully automatic weapons below.

What is an assault rifle?

The state of Minnesota defines "semiautomatic military-style assault weapons" as any one of 17 specific models of semiautomatic firearms, including well-known styles such as the AK-47 and AR-15 rifles and the Uzi semiautomatic pistol. In addition, other makes or models with similar design features or guns modified to resemble the listed styles may be considered assault weapons. These features may include pistol grips (on rifles), detachable magazines or bayonet mounts. Some of these weapons were developed for use by the military but have become popular among civilian gun owners.

Firearms that are "generally recognized as particularly suitable for or readily adaptable to sporting purposes" are not assault weapons.

Are fully automatic weapons ever legal in Minnesota?

Yes, in very limited circumstances. Law enforcement officers, Minnesota National Guard members employed as security guards, chief executive officers of correctional facilities and other prison personnel they authorize may possess fully automatic weapons.

Additionally, ammunition manufacturers who use them solely for testing ammunition, and federally licensed dealers who are authorized to buy, sell or manufacture fully automatic weapons may possess them for use in training of law enforcement officers or for sale to federal, state or local law enforcement agencies. Individuals may also possess certain machine guns that are determined by the Bureau of Criminal Apprehension to be unlikely to be used as a weapon due to age, value, design or other characteristics. Private individuals, dealers or manufacturers must report their fully automatic weapons to the BCA.

These restrictions also apply to short-barreled shotguns.

Under federal law, buyers or transferees of fully automatic weapons manufactured before 1986 must register with the U.S. Bureau of Alcohol, Tobacco and Firearms, pass an extensive background check and pay a $200 tax. Machine guns manufactured after 1986 are banned by the federal Firearm Owners' Protection Act of 1986.

Does Minnesota place any restrictions on magazine capacity?

No.

How about bump stocks?

"Bump stocks," which enable semi-automatic rifles to fire rapidly like fully automatic weapons, exist in a legal gray area, according to a Minnesota Public Radio article published after the devices were used by a gunman who last year opened fire on a country music festival from a Las Vegas hotel room. A law on the books since the 1993 Waco standoff "specifically bans trigger activators, which speed up a gun's rate of fire — like a bump stock does," but bump stocks themselves are not addressed. Machine gun conversion kits, defined as a part or combination of parts intended to convert a weapon into a machine gun, are also illegal.

Who can carry a firearm in public?

Individuals who wish to carry a concealed or unconcealed handgun in public must possess a permit to carry and display it upon request by a law enforcement officer. This permit allows the individual to have a handgun in their clothes or on their person, in a motor vehicle, snowmobile or boat. Law enforcement and on-duty adult correctional facility officers are not required to have a carry permit.

It is illegal to carry a rifle or shotgun in a public place without a permit to carry, except in limited circumstances, such as to or from a gun shop, gun show or while lawfully hunting or target shooting.

To be eligible for a permit to carry, Minnesota residents must submit an application to the county sheriff where they reside. They must be at least 21 years old and a citizen or permanent U.S. resident, have received training in the safe use of a handgun, be eligible to possess a firearm and not be listed in Minnesota's criminal gang investigation system.

Minnesota is a "shall issue" state, as opposed to "may issue," meaning law enforcement authorities do not have discretion to deny a carry permit to anyone who meets the eligibility criteria, unless a determination is made that the applicant is a danger to themself or the public if authorized to carry a handgun.

Individuals with valid carry permits from a handful of other states listed on the Department of Public Safety website may also legally carry in Minnesota. This is known as "reciprocity."

Are guns allowed in schools?

Yes, in very limited circumstances. Law enforcement officers, military personnel or students participating in military training, individuals participating in firearm safety or marksmanship activities on school property, attendees of a gun show held on school property and individuals who are permitted to carry and have written permission from the principal or other senior district administrator may possess a gun on school property.

Those authorized to carry a handgun may store them in a vehicle. In nearly all other cases, possession of a firearm, replica firearm or BB gun on school property is a crime. Members of a color guard may possess a replica firearm or BB gun.

Are gun owners required to be licensed or to register their guns with the state or federal government?

No.

Where can't you have a gun in Minnesota?

Minnesota has a preemption law, meaning local governments cannot enact stricter laws regarding the possession or carrying of firearms than what the state legislature has put in place, though they may regulate the discharge of firearms within their jurisdiction.

Under Minnesota law, nongovernmental entities such as churches, businesses, private colleges and nonprofit organizations may prohibit the possession of firearms on their premises by posting signage with specific language in accordance with state law. Parking facilities may not restrict the lawful possession of firearms. Trespass statutes allow homeowners to prevent the possession of guns on their property, though landlords cannot prohibit tenants from allowing guns in their businesses or residences. Law enforcement officers are exempted from these restrictions.

Possessing a gun in a courthouse or any state building within the state capitol area, other than the Minnesota National Guard Armory, is a felony unless the individual possesses a permit to carry. On-duty law enforcement and military personnel are also exempt.

Federal law prohibits the possession of firearms on federal property, including federal buildings. Individuals can carry guns in national parks as long as they are properly permitted in the state where the park is located and follow the rules for the specific park they are visiting.

CORRECTION: An earlier version of this article incorrectly stated that Minnesota law does not set a minimum age for the purchase of rifles or shotguns. It has been corrected to note federal law prohibits federally licensed dealers from selling a rifle or shotgun to anyone under 18, and under Minnesota law the minimum age to purchase a long gun is 18 in a municipality and 14 outside a municipality. We regret the error. It has also been updated for clarity.