7"/44 caliber gun - Transportation personnel at Naval Support Facility Dahlgren prepare to off-load a World War I-era 7-inch gun on a tracked mount, the first gun originally test-fired to mark the establishment of Dahlgren as a naval proving ground on Oct. 16, 1918. The 7-inch, 45 caliber gun will be restored by the Naval Surface Warfare Center Dahlgren Division.