Firearm background checks are the federal screening step that every licensed gun dealer must run before transferring a firearm to a buyer. The check goes through the FBI’s National Instant Criminal Background Check System, or NICS, which compares your identifying information against national criminal and mental health databases.1Federal Bureau of Investigation. Firearms Checks (NICS) In fifteen states, a state agency runs the check itself using both federal and local records; elsewhere the FBI handles it directly. Most checks come back in minutes with a “proceed.” The rest turn on a specific set of disqualifiers written into federal law, and the penalties for lying your way through the process are as serious as the penalties for possessing a gun you weren’t allowed to buy.
Who Fails a Federal Background Check
The categories of people barred from buying or possessing a firearm come from 18 U.S.C. § 922(g), and they apply in every state.2Bureau of Alcohol, Tobacco, Firearms and Explosives. Identify Prohibited Persons A NICS check will flag you if any of the following applies:
- You have been convicted of a crime punishable by more than one year in prison, in either state or federal court.
- You are a fugitive from justice, meaning you have an active warrant or have fled a jurisdiction to avoid prosecution.
- You are an unlawful user of a controlled substance. A January 2026 ATF rule now requires evidence of “regular use over an extended period” rather than a single failed test or admission.3Federal Register. Revising Definition of Unlawful User of or Addicted to Controlled Substance
- A court or other authority has found you a danger to yourself or others because of mental illness, or you have been involuntarily committed.
- You have been convicted of a misdemeanor crime of domestic violence. The Lautenberg Amendment made this a lifetime ban in 1996, regardless of how old the conviction is.4United States Department of Justice. Criminal Resource Manual 1117 – Restrictions on the Possession of Firearms by Individuals Convicted of a Misdemeanor Crime of Domestic Violence
- You are subject to a court order restraining you from harassing, stalking, or threatening an intimate partner or that partner’s child.
- You were discharged from the military under dishonorable conditions.
- You have formally renounced your U.S. citizenship.
- You are in the country without legal status, or you hold a nonimmigrant visa without qualifying for a narrow exception like a valid U.S. hunting license.
Possessing a firearm while falling into any of these groups carries up to 15 years in federal prison.5Office of the Law Revision Counsel. 18 USC 924 – Penalties With three or more prior violent felony or serious drug convictions, 15 years becomes the mandatory minimum.
The Marijuana Problem
Marijuana is still a controlled substance under federal law, even in states that have legalized it. Regular users are prohibited from buying firearms, and a state medical marijuana card offers no protection: federal law doesn’t recognize marijuana prescriptions. The 2026 rule change means a single positive test or a single admission of past use no longer triggers a denial by itself, but ongoing use documented by other evidence still will.3Federal Register. Revising Definition of Unlawful User of or Addicted to Controlled Substance
Age Floors
Licensed dealers cannot sell a handgun or handgun ammunition to anyone under 21, and cannot sell a rifle, shotgun, or their ammunition to anyone under 18.6Office of the Law Revision Counsel. 18 USC 922 – Unlawful Acts Some states set higher minimums.
How the Check Actually Runs
Before the dealer contacts NICS, you fill out ATF Form 4473, the Firearms Transaction Record.7Bureau of Alcohol, Tobacco, Firearms and Explosives. ATF Form 4473 – Firearms Transaction Record It asks for your name, date of birth, place of birth, address, and sex, plus yes-or-no questions covering each prohibited category. You’ll need a government-issued photo ID showing your name, date of birth, and current address. If the address on your ID is out of date, you’ll need a supplemental document proving where you live now. Every detail on the form must match your ID exactly; a mismatch stops the process before a check is even submitted.
The Social Security number field is optional, but providing it helps distinguish you from other people with similar names and reduces the chance of a delay. Nonimmigrant visa holders must show they qualify for one of the exceptions to the general ban, such as a valid U.S. hunting license.8eCFR. 27 CFR 478.120 – Firearms or Ammunition Imported by or for a Nonimmigrant Alien
The dealer then submits the check through a secure portal or by phone. NICS searches three national databases (the National Crime Information Center, the Interstate Identification Index, and the NICS Indices) and returns one of three results:
- Proceed. No disqualifying record was found and the sale can be completed.
- Delayed. Something in the databases needs an examiner’s review before a final answer.
- Denied. A disqualifying record was found and the sale cannot go forward.
Most checks resolve on the spot. When a check comes back delayed, the FBI has three business days to reach a determination. If that window closes without an answer, the dealer may legally transfer the firearm, though no dealer has to.9Federal Bureau of Investigation. About NICS – Section: How Firearms Background Checks Work The FBI keeps working the case even after that deadline and can still issue a denial, which triggers retrieval efforts if the gun already changed hands.
Enhanced Checks for Buyers Under 21
The Bipartisan Safer Communities Act added a heavier screening layer for buyers who haven’t turned 21. NICS examiners must contact the buyer’s state juvenile justice system, mental health records custodian, and local law enforcement to look for disqualifying information that isn’t in national databases.10Federal Bureau of Investigation. NICS Enhanced Background Checks for Under-21 Gun Buyers Showing Results If that outreach turns up something worth investigating, the check window stretches from three business days to 10.11Federal Register. Bipartisan Safer Communities Act of 2022 and Consolidated Appropriations Act of 2022 Implementation Juvenile records are frequently sealed or held apart from adult criminal history systems, and the enhanced check is the only mechanism that reaches them.
When No Check Is Required
Federal law requires a NICS check for every sale by a licensed dealer, called a Federal Firearms Licensee. That covers gun shops, sporting goods retailers, and any licensed dealer working a gun show table. A private, unlicensed seller transferring a gun to another resident of the same state is not federally required to run a check. Around 20 states and the District of Columbia have closed that gap by requiring background checks on private sales as well.
The line between a private seller and someone who legally needs a dealer’s license moved under a 2024 ATF rule implementing the Bipartisan Safer Communities Act. Anyone who devotes time and effort to buying and reselling firearms predominantly for profit is now “engaged in the business” and needs a license.12Federal Register. Definition of Engaged in the Business as a Dealer in Firearms Flipping firearms within 30 days of purchase, advertising a willingness to supply more, or renting show tables to display inventory can all create a legal presumption that you’re a dealer. Someone occasionally selling from a personal collection, giving a gun as a gift, or liquidating inherited firearms generally stays on the private side.
Interstate transfers are more restrictive. An unlicensed person generally cannot transfer a firearm directly to a resident of another state.6Office of the Law Revision Counsel. 18 USC 922 – Unlawful Acts Handguns must move through a licensed dealer in the buyer’s home state. Long guns can move across state lines through a dealer if the transaction complies with both states’ laws. Firearms inherited after a death and temporary loans for lawful sporting purposes are treated separately.
Lying on the Form and Straw Purchases
Every question on Form 4473 carries a signature under penalty of perjury. Lying is a separate federal crime with up to 10 years in prison, even if the sale never goes through.13Bureau of Alcohol, Tobacco, Firearms and Explosives. Federal Prosecutors Aggressively Pursuing Those Who Lie in Connection with Firearm Transactions
A straw purchase is buying a firearm on paper for yourself when you’re actually acquiring it for someone else, especially someone who couldn’t pass a check or intends to use it in a crime. Congress created a dedicated offense for this in 2022 under 18 U.S.C. § 932, carrying up to 15 years in prison and a $250,000 fine.14Office of the Law Revision Counsel. 18 USC 932 – Straw Purchasing of Firearms The ceiling climbs to 25 years if the firearm is used in a felony, terrorism, or a drug trafficking crime. Buying a firearm as a genuine gift for someone who is legally eligible to own one is not a straw purchase. Buying one for a friend who hands you the cash is.
What to Do If You’re Denied
Denials sometimes come down to mistaken identity, outdated records, or information that belongs to someone with a similar name and birthdate. If you’re denied, you can request the reason and challenge the decision.15Federal Bureau of Investigation. Requesting a Reason for and/or Challenging a NICS Denial
You submit a written request, online or by mail, to the FBI’s NICS Appeal Services Team along with the NICS Transaction Number from the failed check. The FBI will tell you which record caused the denial. You can then submit documentation showing the record is wrong, outdated, or someone else’s. Criminal history disputes often require you to submit fingerprints so the FBI can confirm identity. If the administrative appeal doesn’t resolve the problem, 18 U.S.C. § 925A lets you file a civil lawsuit.
If you keep getting caught in the same false match, the FBI’s Voluntary Appeal File offers a longer-term fix. After a successful application, you receive a Unique Personal Identification Number to write on future Form 4473s, and the UPIN links directly to your pre-cleared file so NICS can bypass the mistaken hit.16Federal Bureau of Investigation. Voluntary Appeal File
Getting Firearm Rights Back After a Disqualification
Losing your firearm rights isn’t always permanent, and the way back depends on why you lost them. A presidential pardon for a federal conviction, or a governor’s pardon for a state conviction, generally removes the federal firearm disability. So does an expungement, a reversal, a set-aside, or a full restoration of civil rights under state law. The catch: if the pardon, expungement, or restoration order specifically says you still can’t possess firearms, or if state law doesn’t fully restore your firearm rights, the federal ban stays in place.17Bureau of Alcohol, Tobacco, Firearms and Explosives. 27 CFR 478.142 – Effect of Pardons and Expunctions of Convictions
A second, separate path exists under 18 U.S.C. § 925(c), which lets a prohibited person petition the Attorney General for relief from firearms disabilities. You have to show that you’re unlikely to endanger public safety and that granting relief wouldn’t be contrary to the public interest. Congress has historically blocked ATF funding for processing these individual applications, making approvals rare. In February 2026, the Attorney General granted relief to a group of applicants and published the decisions in the Federal Register.18Federal Register. Granting of Relief Federal Firearms Privileges The route exists on paper, and appears to be moving again, but it remains difficult and uncertain.