Wachtmeister Hugo Primozic
One of the greatest Sturmgeschutz aces was Wachtmeister Hugo Primozic of StuG battalion 667, who was noted for his quick reactions, clever tactical use of ground and the icy nerve which in tense situations enabled him to hold his fire until his opponent had closed to point-blank range. In a five-month period of fighting he was awarded the two grades of the Iron Cross, the Knight's Cross and the Oak leaves. Primozic became the first NCO in the history of the German Army to be awarded the Knight's Cross. 

Born in 1914, Primozic joined the Reichswehr and fought in the French campaign as a field artillery gunner. In 1942 he joined the 667th Sturmgeschutz battalion which was sent to the Eastern Front. In September 1942, his three-gun troop, fighting in isolation, routed a determined Russian breakthrough attempt at Rzhev, destroying a total of 24 enemy tanks. Allowing the Russian tanks to advance, the StuG crews aimed at the most dangerous opponents first, killing them with one round at a short distance. By January 1943 Primozic had 60 personal kills to his credit and after an equally gallant action on the 28th he was awarded the Oakleaves, being simultaneously commissioned with the rank of Lieutenant. 

Repairing a broken track while being under fire...
September 1942: 24 enemy tanks of tankbrigade Stalin destroyed 
" Wachtmeister Primozic destroyed tanks day after day during an enemy offensive. One the fourth day, he had to cover the flank of his division, but during that day he fired his last shell... He had to retreat to escape from encirclement by breaking through... There was another StuG, immobilized, and while the Russians were closing in, Primozic came out of his vehicle to connect both vehicles, and drove both back to their own lines..."  

From a special report in the German propaganda magazine Signal
As described above, Primozic was able to connect both vehicles of his platoon with a steel wire rope, and had to fight off the surrounding Russian infantry with a machine gun. For this action he was awarded the Iron Cross First Class.

Wachtmeister Primozic pulls out a disbled StuG of his platoon 
in front of the advancing Russians 
 

rigth: Oberwachtmeister Hugo Primozic, 
who was the first NCO to be awarded the Oak Leaves

In September 1942 a large Russian army (including the Stalin Tank Brigade) tried to attack the town and area of Rzhev. As Primozic told: " On september the 15th we had only two StuGs ready, when the Russians wanted to break through. There was heavy artillery fire, and we had to hide in trenches untill the storm was over. When the artillery barrage ended, the first enemy tanks already passed our positions, while we still had to climb aboard our guns." Moving from position to position, the StuG platoon was fighting both tanks and infantry. Primozic destroyed 24 tanks on that particular day, first those who had broken through, often with one shot. For this action Primozic was awarded the Knight's Cross and promoted to senior sergeant.