Gun sales from licensed firearm dealers, also known as Federal Firearm Licensees (FFLs), typically require a federal firearm background check.  This is true even if a firearm is purchased online. There are two main exceptions to the background check requirement for firearm purchases:

1. 21 states have their own background check that can be used instead of the federal system, and system
2. Some states have concealed carry licenses/permits that allow a purchaser to skip the background check for a firearm purchasebecause one was already done for their permit/license.

The FBI’s National Instant Criminal Check System (NICS) is our federal firearm background check system used by FFLs. Therefore, a strong indicator of relative firearm sales for any given month is to see how many NICS checks have been processed. The NICS number of background checks is not a direct indication of the number of firearms sold, however, for a few reasons:

1. Some background checks find criminal issues that result in a cancelled/denied sale,
2. Some firearm sales don’t have federal background checks (see above), and
3. In rare circumstances, some states use the NICS system for permit renewals that aren’t tied to actual firearms sales.

Despite these potential inconsistencies in NICS numbers, the total number of background checks is still a reliable source for seeing trends in the industry. For a more accurate picture of which NICS checks might be related to actual firearm sales, the firearms industry’s trade association, the National Shooting Sports Foundation (NSSF), adjusts the raw NICS background check data with their own research to try to paint a more accurate picture.