Background checks were processed at a rate of nearly three per second as Black Friday gun shoppers took advantage of huge discounts in soft gun market.

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.

The number of FBI NICS background checks processed during a given time period provides a rough look at the number of firearms purchased in a given time period.

It is not a true count of the number of firearms purchased, however, as one background check can reflect the sale of any number of firearms by a given purchaser at a given time. Also, there are many states where a concealed carry permit is used instead of a NICS check, and the number of people with concealed carry permits has skyrocketed in recent years.

Roughly 92-percent of NICS background checks will result in permission to immediately “proceed” with a sale. The majority of the remainder will be given a “delay” for having some personally identifying information that matches that of a prohibited person.

Only 0.95% of sales will ultimately be denied, because criminals do not buy guns from gun stores.