Kim Anh Vo, 20, was taken into custody Tuesday in Richmond County.
The sailor was assigned to the Norfolk-based aircraft carrier George H.W. Bush when prosecutors say he unlawfully sold at least 23 guns for profit.
The outer armory door, the weapons vault and all of the weapons racks were unlocked.
NCIS agents executed arrest warrants Wednesday in connection to a sextortion ring that has victimized hundreds of service members.