the Zipgun callsign was used by the 23 TASS OV-10s detached to U-Tapao, from about May 70 to Possibly Nov 70 (may have lasted longer). We flew in southwest Cambodia from the Ton Le Sap Lake to the Thai border. This was Cambodian Military Region 3, Headquartered at Battambang.
 
Trey Moran Nail/Zipgun 13