Since November 30, 1998 due to the Brady handgun Violence Prevention Act of 1993 all Federal Firearms Licensees must perform a background check on everyone who intends to purchase a firearm. When you intend to purchase a firearm from an FFL dealer, you fill out ATF Form 4473. The form is ran through a division of the FBI and instantly the person is either flagged with proceed, deny or delay. There could be any number of things that show up on a back ground check that will deny you ownership. The ATF has a list of who cannot own a firearm.
It is not required to run a background check on person-to-person individual sales, inheritances and gifts of firearms. However, by law those who are prohibited from owning a firearm are still prohibited from possessing a firearm. It is illegal to give a firearm to someone who cannot legally own it.
Proponents of a universal background system or expanded background checks say that it will keep guns out of the hands of a criminals and the mentally ill. They think our current system is not working. However, since the end of 2012, over 980,000 NICS checks returned denied.
ATF Agent Jeff Wachtel says, "Let's be honest, if someone wants a gun, it's obvious the person will not have difficulty buying a gun, either legally or through the extensive United States black market." Seventy nine percent of convicted criminals involved in gun crimes report obtaining their gun from the street or from a friend or family member. The other percent receive guns from theft or corrupt FFL dealers.
The Federal Firearms License was established to implement the Federal Firearms Act of 1938. The FFA required all manufacturers and dealers of firearms who ship or receive firearms or ammunition in interstate or foreign commerce to have a license, and forbade them from transferring any firearm or most ammunition to any person interstate unless certain conditions were met.  As a practical matter, this did not affect the interstate commerce in firearms or ammunition. It was with the adoption of the Gun Control Act of 1968, which repealed most of the FFA, that the lawful interstate trade of firearms was limited almost entirely to person holding a Federal Firearms License in the United States.