All Federal Firearms Licensees should be aware that there are prohibited categories of buyers of firearms and ammunition.  If we tell you there are nine categories of prohibited buyers of firearms and ammunition, how many can you recall from memory?  It could mean prison for up to ten years if you conduct a sale to a person in one of these categories, which should be sufficient motivation for you to work at the answer. The Gun Control Act of 1968 makes it is unlawful for you to sell or dispose of any firearm or ammunition to another person when you know or have reason to believe that the other person is in one of more of the following categories: (1) under indictment or been convicted of a felony; (2) a fugitive from justice; (3) abusive of any controlled substance; (4) adjudicated as suffering from mental health issues; (5) an illegal alien or an alien admitted under a non-immigrant visa; (6) dishonorably discharged from the Armed Forces; (7) renounced of United States citizenship; (8) subject to a restraining court order prohibiting harassing, stalking, or threatening an intimate partner or child; or (9) convicted of a misdemeanor crime of domestic violence. As a practical matter, using the FBI’s NICS to conduct a background check is your first line of defense against engaging in an illegal sale.  Nearly 70% of federal denials using NICS are because the would-be buyer has been convicted of a felony or has been convicted of a misdemeanor crime of domestic violence.  Another near 10% of federal denials during an NICS background check are because the person trying to buy the gun is a fugitive from justice.  Approximately 80% of federal NICS denials happen when customers are counting on a seller who does not follow compliance requirements of processing ATF Form 4473 and performing a background check.   In spite of all of the press coverage on mental health relative to firearms, only about 1% of federal NICS denials are returned for an adjudication of mental health issues.  This may be due, in part, to the incomplete mental health information uploaded by states to NICS.  Even so, the category of an adjudication of a mental health issue is only a small fraction of mental health patients, reflecting persons found to be incompetent, persons involuntarily committed, and the criminally insane.  Whenever an NICS background check results in a denial, you cannot complete the purchase.  At the point you receive the federal NICS denial, you “know” that the customer meets one of the Gun Control Act prohibited purchasers categories.  To proceed with the sale would be to engage in an unlawful act that could subject you to up to ten years in prison. If you find yourself faced with a mental block when trying to remember these nine categories of prohibited buyers, if you’re an FFL for sales of firearms and ammunition the information is always at hand – the list is on Form 4473.  So, if you can’t remember all nine categories, at least remember where to find the answer.