What Is a Background Check and How Does It Work
Woody's answers are based on published federal and state law. Not legal advice. Consult a licensed attorney for your specific situation.
A background check is a federal screening process that verifies your legal eligibility to purchase firearms through the National Instant Criminal Background Check System (NICS). Licensed dealers must run this check before completing any firearm transfer.
What This Means for You
Every time you buy a firearm from a Federal Firearms License holder, they're legally required to verify you can legally own that gun. This applies whether you're buying a complete rifle, a stripped lower receiver, or any other firearm component that requires transfer through an FFL. The system exists to prevent prohibited persons from acquiring firearms through legal channels.
The Detail
The background check process starts when you fill out ATF Form 4473 at your local gun store. The dealer then contacts NICS, which searches three main databases: the National Crime Information Center, the Interstate Identification Index, and the NICS Index. These databases contain records of criminal convictions, restraining orders, mental health adjudications, and other disqualifying factors.
NICS responds with one of three answers: proceed, deny, or delay. A proceed means you're clear to complete the transaction immediately. A deny blocks the sale entirely. A delay means the system needs more time to research your records, and if no definitive answer comes back within three business days, the dealer can legally complete the transfer at their discretion.
Certain purchases require additional screening beyond the standard NICS check. NFA items like suppressors, short-barreled rifles, and machine guns go through a much more intensive process involving fingerprints, photographs, and approval that can take months. Some states also impose waiting periods or additional state-level background check requirements that run parallel to the federal system.
The system has some notable gaps. Private sales between individuals in most states don't require background checks, and the databases aren't always complete or up to date. Some states have implemented universal background check laws that close the private sale loophole, while others rely solely on the federal framework.
Build Impact
If you're building an AR-15, you'll need a background check to buy the stripped or complete lower receiver, since that's the legally regulated firearm component. Everything else can typically be purchased without additional screening, though some states restrict certain parts like high-capacity magazines.