The busiest shopping day of the year also saw a major boom for gun sales , with the federal background check system setting a record of more than 175,000 background checks Friday , according to the FBI . The staggering number of checks -- an average of almost three per second , nearly three times the daily average -- falls on the shoulders of 600 FBI and contract call center employees who will endure 17-hour workdays in an attempt to complete the background reviews in three business days , as required by law , FBI spokesman Stephen Fischer said . `` Traditionally , Black Friday is one of our busiest days for transaction volume , '' Fischer said . Indeed , Friday saw the highest number of background checks ever for a Black Friday , and second in history . The highest day on record was December 21 , 2012 , with more than 177,000 background checks . On average , more than 500 gun background checks a day fail because of incomplete information required for a decision , according to the FBI 's National Instant Criminal Background Check System , which is responsible for checks on firearm purchases from federally licensed shops . Employees of the background check agency , who work every day but Christmas , worked through the weekend to vet Friday 's purchases . `` We are averaging three checks per second , '' Fischer said Friday afternoon , before the final numbers were in . `` The challenge is to have staff keep up with this volume . We do that by limiting personal leave , asking employees to work extra shifts and reutilizing former ... employees to serve in NICS during this busy period . '' The agency brings in 100 extra employees to deal with the increase . `` This means saving lives and protecting people from harm -- by not letting guns fall into the wrong hands , '' FBI Manager Kimberly Del Greco said in a statement . `` It also ensures the timely transfer of firearms to eligible gun buyers . '' Opinion : Black Friday 's liability risk for stores . Overall , about 186,000 background checks a year can not be completed , according to the FBI . It 's difficult to know exactly how many gun sales are authorized from that number because whether to make the sale is ultimately in the hands of the shop owner . Last year , the agency completed 21 million background checks , and about 1.1 % of those purchases were denied , the agency said . Firearm background checks have doubled from the more than 9 million conducted when the system was implemented in 1999 . Ten factors can disqualify a purchase : felony conviction , arrest warrant , documented drug problem , mental illness , undocumented immigration status , dishonorable military discharge , renunciation of U.S. citizenship , restraining order , history of domestic violence or indictment for any crime punishable by longer than one year of prison . Gun purchasers are required to fill out a form from the Bureau of Alcohol , Tobacco , Firearms and Explosives with basic identification information and questions about the 10 disqualifying factors . The history of Black Friday . The gun shop can read the information to the background check agency over the phone or run the information through a secure Internet connection . The check sometimes involves calling courthouses to get records and dispositions . `` We wo n't make a determination unless we are absolutely sure , '' Fischer said . However , the agency can not deny a transaction based on an arrest without knowing the disposition of a case . After the three business days have passed , completion of the sale becomes the prerogative of the licensed gun shop owner , according to the Brady Handgun Violence Prevention Act of 1998 . Fischer said major retailers such as Walmart , Dick 's Sporting Goods , Cabela 's and Gander Mountain usually wo n't go through with the sale without complete information . Injuries , arrests as 'Black Friday ' shopping tradition spreads to UK .
This was the busiest Black Friday ever for gun background checks . Score: 7 Black Friday brings nearly three times daily average of gun background checks , FBI says .