Key Takeaways
- Federal law requires licensed firearms dealers to run a background check through the FBI's NICS system before a sale, screening for prohibitors such as felony convictions and involuntary mental health commitments.
- Unlicensed private sellers who are not "engaged in the business" of dealing firearms have no federal duty to run a background check, whether the sale happens at a gun show, online, or in person.
- About 20 states and the District of Columbia require checks on some or all private sales, so the rules a buyer faces depend heavily on where the sale takes place.
If you buy a gun at a sporting goods store, a background check is almost certain. But what if you buy the same gun from a stranger at a gun show, or from someone you found through a website? Does federal law require a check then?
In this TalksOnLaw Brief, Jake Charles, Associate Professor of Law at Pepperdine Caruso School of Law and a Second Amendment scholar, explains how the national background check system works, where its coverage stops, and what people mean when they talk about the "gun show loophole."
How Federal Background Checks Work
Professor Charles explains that background checks are one of the few parts of gun regulation handled at the national level. Anyone in the business of selling firearms, which he describes as selling with the predominant purpose of earning a profit, must be federally licensed and must run a check before any sale. At a store like Walmart or Dick's Sporting Goods, the check runs through a centralized FBI system, the National Instant Criminal Background Check System (NICS), which queries several databases for disqualifying statuses such as a felony conviction, a past involuntary mental health commitment, or a dishonorable discharge from the military. If nothing turns up, the sale proceeds. In general, he notes, the check happens every time you buy from a licensed dealer, though some permits can substitute for a new check.
He also points to a gap after the sale. Because there is no national registry of gun buyers, someone who passes a check and later becomes disqualified cannot easily be identified. Some states, such as California, keep more comprehensive records that allow guns to be recovered from people who become prohibited.
The Private-Sale Gap
The "gun show loophole," Professor Charles explains, is something of a misnomer. Licensed dealers who sell at gun shows still have to run checks. The gap concerns unlicensed private sellers, who have no federal duty to run a check because they are not "in the business" of selling guns. Those sales can happen at gun shows, privately, or through online marketplaces such as Armslist, sometimes called the "Craigslist for guns." About 20 states and the District of Columbia require broader checks. Because there is no registration system, the volume is hard to measure, but he cites survey-based estimates that roughly a quarter of guns are acquired outside the system that requires a check, likely millions of guns each year.
What to Know Now
The framework Professor Charles describes remains in place: licensed dealers run checks, and most private sales between unlicensed individuals still fall outside federal law. The Bipartisan Safer Communities Act of 2022 adjusted that framework. It defined being engaged in the business as dealing to "predominantly earn a profit," the standard he describes, and it added an enhanced check for buyers under 21 that reaches juvenile and mental health records. In 2024, ATF issued a rule spelling out when frequent sellers must become licensed, which aimed to bring more private sellers into the system; the rule drew court challenges, and in 2026 ATF proposed rescinding most of its added definitions and presumptions while keeping the statutory standard. Separately, in Bondi v. VanDerStok (2025), the Supreme Court upheld ATF's rule treating many build-it-yourself "ghost gun" kits as firearms, so kits sold by licensed dealers now come with serial numbers and background checks. Supporters of universal background checks see the private-sale gap as a priority for Congress, while opponents argue such mandates burden lawful owners and are hard to enforce without registration. For now, state law remains the main source of variation.
