Gun Purchase Requirements: Age, ID, Form 4473, and NICS Checks

To buy a gun from a licensed dealer in the United States, you have to meet the federal gun purchase requirements: be old enough for the firearm type, fall outside the categories of people federal law prohibits from owning guns, show valid government-issued photo ID, fill out ATF Form 4473 truthfully, and pass a background check through the National Instant Criminal Background Check System (NICS). Your state may add more on top of that, and often does.

How Old You Have to Be

Federal law sets two age floors. You must be at least 18 to buy a rifle or shotgun from a licensed dealer, and at least 21 to buy a handgun. Some states have raised the minimum to 21 for all firearms, so the federal age is the floor rather than the ceiling.¹

Buyers between 18 and 20 also face an enhanced background check under the Bipartisan Safer Communities Act, signed in June 2022. NICS reaches out to state and local agencies for juvenile court records and mental health adjudications, and if the system flags something the review period stretches from three business days up to ten.²

Who Federal Law Prohibits From Buying

Under 18 U.S.C. § 922(g), nine categories of people cannot buy or possess firearms, and the background check is built to catch them.³ You are prohibited if you:

Have been convicted of a crime punishable by more than one year in prison. The potential punishment controls, not the sentence actually served.
Are a fugitive from justice.
Are a current unlawful user of, or addicted to, a controlled substance. This includes marijuana, even in states where it is legal, because federal law still treats it as a controlled substance.
Have been involuntarily committed to a mental institution or adjudicated mentally unfit by a court.
Are unlawfully present in the U.S., or hold a nonimmigrant visa (with narrow exceptions).
Received a dishonorable discharge from the military.
Have renounced U.S. citizenship.
Are subject to a qualifying domestic violence restraining order issued after a hearing you had notice of.
Have a misdemeanor domestic violence conviction, which carries a lifetime federal ban under the Lautenberg Amendment.

Citizenship and Where You Live

U.S. citizens and lawful permanent residents with a valid green card can buy firearms. Nonimmigrant visa holders are almost entirely barred from buying at a licensed dealer, with narrow exceptions such as holding a valid state-issued hunting license or serving as an accredited foreign government official. Even under an exception, they generally must show at least 90 continuous days of residency in the state where the purchase occurs.⁴

Residency also controls where you can shop. A licensed dealer cannot sell you a handgun if you live in a different state. Rifles and shotguns can cross state lines, but the sale has to comply with the laws of both states.³ Most out-of-state handgun purchases work by shipping the firearm to a licensed dealer in your home state, where you complete the paperwork and background check.

What You Bring to the Counter

You need a valid government-issued photo ID showing your full legal name, date of birth, and current address. A driver’s license is the standard document. If your license shows an old address, bring a second government document proving where you currently live, such as a voter registration card or vehicle registration. Without proof of your current address, the dealer cannot complete the sale.

Some states also require a purchase permit, firearms identification card, or safety certificate before a dealer can begin the transaction. These are separate applications, usually through local law enforcement, and may involve fingerprinting, a safety course, and fees that vary by jurisdiction. If your state requires one, show up without it and you go home empty-handed regardless of your background check.

ATF Form 4473

Every sale at a licensed dealer starts with ATF Form 4473, the Firearms Transaction Record. You fill in your personal information and answer yes-or-no questions that track the prohibited categories above. You also certify under penalty of perjury that you are the actual buyer, not purchasing on behalf of someone else. Providing your Social Security number is optional but strongly recommended, because it reduces the chance of a delay from a name match with someone else’s record.⁵

Lying on Form 4473 is a federal felony carrying up to five years in prison.⁶ If the lie amounts to a straw purchase, the exposure gets much worse.

The NICS Background Check

Once the form is done, the dealer contacts NICS, run by the FBI. Some states run the check through their own agency as a point of contact, but the underlying databases are the same: the National Crime Information Center, the Interstate Identification Index, and the NICS Index.⁷

You get one of three results. A Proceed means no disqualifying records were found and the dealer can transfer the firearm. A Denied means a matching record blocks the sale. A Delayed means the system found something that needs an examiner’s review. Federal law gives the FBI three business days on a delay; if no final answer comes back in that window, the dealer is allowed (but not required) to complete the transfer.³ Some dealers wait for a definitive response either way.

A clean NICS check doesn’t override a state waiting period. Some states impose a cooling-off period of several days to over a week before you can take the gun home, and that clock runs on its own.

State Rules Layered on Top

Federal requirements are the floor. States commonly add mandatory waiting periods, purchase permits with their own application and approval process, safety training, registration of purchased firearms, and limits on how many guns you can buy in a set period. A few states maintain broader prohibited-person categories than federal law.

If your state has an extreme risk protection law (a “red flag” law), a family member or law enforcement officer can petition a court to temporarily remove your firearms and block new purchases if there’s evidence you pose a danger. More than 20 states and the District of Columbia have these laws, and the Bipartisan Safer Communities Act provides federal grants to help states implement them.² The orders require court hearings, but they can block a purchase you’d otherwise pass.

Check your state’s specific rules before you go. The dealer will know them, but if you don’t have the required permit or certificate in hand, no dealer can start the paperwork.

Private Sales Work Differently

Everything above applies to licensed dealers. Federal law does not require a background check when one private individual sells a gun to another, provided both live in the same state and the seller has no reason to believe the buyer is prohibited.³ No Form 4473, no NICS check, no federal record. A growing number of states have closed this gap by requiring all sales, including private ones, to run through a licensed dealer. If your state hasn’t, a private sale can legally happen with nothing more than a handshake, though the seller still can’t knowingly transfer to a prohibited person.

Straw Purchases

Buying a gun for someone else who asked you to purchase it on their behalf is a straw purchase, and it’s one of the most heavily prosecuted federal firearms offenses. Under 18 U.S.C. § 932, added in 2022, a straw purchase carries up to 15 years in federal prison and a $250,000 fine. If the firearm is linked to a felony, an act of terrorism, or drug trafficking, the maximum climbs to 25 years.⁸

Buying a firearm as a genuine gift for someone who is legally eligible to own one is fine. Buying it because they asked you to, or because they can’t pass a check themselves, is not. That’s what the “actual buyer” certification on Form 4473 is designed to catch.

If You Get Denied

You can challenge a denial. The FBI must provide the general reason within five business days of your inquiry, and from there you submit a formal appeal in writing, by fax, or online. You’ll need your full name, mailing address, and the NICS Transaction Number from the dealer’s paperwork.⁹

The most common successful appeal is mistaken identity, where your information matched someone else’s record. Submitting a set of rolled fingerprints through a law enforcement agency can prove you aren’t that person. If the denial rested on an outdated record, like an expunged conviction or a dismissed restraining order, court documentation can get the record corrected. Incomplete appeals get rejected outright, so include everything the FBI asks for in a single submission.¹⁰

1
Bureau of Alcohol, Tobacco, Firearms and Explosives. Minimum Age for Gun Sales and Transfers
2
Congress.gov. Bipartisan Safer Communities Act – Text
3
Office of the Law Revision Counsel. 18 USC 922 – Unlawful Acts
4
Bureau of Alcohol, Tobacco, Firearms and Explosives. Nonimmigrant Aliens Purchasing Firearms and Ammunition in the United States
5
Bureau of Alcohol, Tobacco, Firearms and Explosives. ATF Form 4473 – Firearms Transaction Record
6
Office of the Law Revision Counsel. 18 USC 924 – Penalties
7
Federal Bureau of Investigation. Firearms Checks (NICS)
8
Office of the Law Revision Counsel. 18 USC 932 – Straw Purchasing of Firearms
9
Federal Bureau of Investigation. Requesting Reason for and/or Challenging a NICS-Related Denial
10
Federal Bureau of Investigation. NICS Guide for Appealing