The "K 39" and its variants served as mobile artillery only with "Artillery Battalions (Artillerie-Abteilungen) 767" and "768", each battalion being organized with 3 batteries, each with two guns. Both battalions were raised in April—May 1940, but it is unknown if either participated in the Battle of France. For Operation Barbarossa "767" was assigned to the Sixth Army of Army Group South where it participated in the sieges of Odessa and Sevastopol. "768" was initially assigned to 4th Army of Army Group Center, but it was quickly transferred to Army Group North to aid in the siege of Leningrad. By the start of Case Blue in late June 1942, "Artillery Battalion 767" had been converted to smaller guns, but "768" was assigned to the 18th Army of Army Group North.