When an individual is denied the transfer of a firearm, they may initiate an appeal by accessing http://www.fbi.gov/nics-appeals. Individuals that do not have internet access may appeal the decision in writing directly to:
Federal Bureau of Investigation
Appeal Services Unit
PO Box 4278
Clarksburg, WV 26302-9922
Appeals submitted in writing must include the NICS Transaction Number (NTN) and a valid address for the appellant.
You may obtain an Appeal Brochure online at: http://www.fbi.gov/about-us/cjis/nics/appeals/nics_appeals_brochure_eng