a "federal database" is NOT going to include stolen guns,and will not include FEDGOV and military guns.
FEDGOV is "missing" over 1000 of their guns as of 2003,some being full-auto machine guns. that does not include US military arms losses. Then state and local law enforcement have guns stolen from their vehicles frequently. Former Orlando POLICE CHIEF Val Demings had her service handgun stolen from her unmarked SUV,and over a year later,it still hasn't been recovered. OPD has "lost" 2 AR-15 kits,and had 2 machine guns stolen from vehicles.
guns will ALWAYS be available to those who really want them.