This pistol was issued in 1946 by the Naval Gun Factory in D.C. to a LtJg. who was a courier for Operation Crossroads at Bikini Atoll. Operation Crossroads was the first nuclear test after the war, which consisted of two detonations, Shot Able and Shot Baker. I have the original documents and all the equipment that came with it...
http://www.fototime.com/{FC93173E-9F...A}/picture.JPG
