How Firearm Background Checks Work

Performing a Background Check

A customer walks into a licensed gun store and chooses the model(s) to purchase. Before any money changes hands, he or she fills out ATF Form 4473, which in addition to asking for name, address, citizenship and other basic information, will ask whether the buyer has been convicted of a crime with imprisonment of more than one year; is a fugitive from justice; is addicted to drugs; judged mentally defective; or unlawfully living in the U.S., among other criteria.

Once the form is filled out, the gun dealer then either picks up the phone or goes online to reach the NICS division at the FBI, or a state agency that acts as an NICS "Point of Contact" (POC) and has access to the FBI system. A licensed gun dealer in a POC state contacts the state agency instead of the FBI [source: FBI].

The dealer submits the supplied Form 4473 responses. The NICS searches for records matching that potential buyer with any of the prohibited criteria listed on the form. The system automatically searches three databases:

  • Interstate Identification Index, a nationwide database of criminal records
  • National Crime Information Center, a nationwide database of restraining orders and outstanding warrants
  • NICS Index, a supplemental database of people identified by state and federal sources as ineligible to purchase a gun, including people in the United States illegally and those with documented mental illnesses that would indicate a threat to public safety.

If the potential gun buyer is not a U.S. citizen, the search extends to databases maintained by the U.S. Immigration and Customs Enforcement agency [source: Bureau of Justice Statistics].

In less than a minute, the gun dealer receives one of three responses: "Proceed" with the sale, indicating no matches were found; "deny" the sale, indicating at least one definitive match; or "delay" the sale, indicating at least one possible match [source: FBI].

With a "delay," the clock starts running on a three-day waiting period. The FBI has exactly 72 hours to gather additional information from sources not automatically searched by the NICS, which can include contacting state or local law-enforcement or court authorities directly. If the FBI can confirm the match, a "deny" response is returned to the gun dealer; if the FBI can disprove the match, a "proceed" response is returned; and if the FBI is unable to do either (or just doesn't respond) by the end of the three days, it is within the gun dealer's discretion whether or not to proceed with the sale [source: FBI].

Regardless of the response, the FBI must destroy all records generated by the background check within 24 hours of returning a decision. The only exception to this is the Voluntary Appeal File (VAF). The gun seller is not told the reason for the "deny" and so cannot tell the prospective buyer. But the denied person can find out by writing to the FBI or state POC. He or she can also file an appeal, in which case the FBI reviews its decision in light of any additional information or corrections provided by the denied buyer. If the appeal is granted, the sale can proceed [source: FBI].

The system seems pretty straightforward. And yet, there are some serious limitations.