The 20 mm autocannon was used in the T-60 tank, as well as on Soviet aircraft. It would take quite a Rambo character to carry one. Although, maybe it was meant for this guy:
"On July 13th, 1941, Red Armyman Ovcharenko was transporting ammunition for the 3rd company in the Pesets region, and was 4-5 kilometers from his unit. In that region, two armoured cars, 50 German soldiers, and 3 officers surrounded him.
A German officer exited the car, and ordered Ovcharenko to raise his hands, took his rifle, and started questioning him. Ovcharenko had an ax in his cart. He grabbed the ax, chopped off the officer's head, and threw three grenades at a nearby car. 21 German soldiers were killed, the rest ran in panic. Ovcharenko pursued a wounded officer through a garden in the Pesets village, caught him, and also chopped his head off. The third officer ran away.
Comrade Ovcharenko calmly collected the documents of the dead, the officers' maps, papers, diagrams, notes, and delivered them to the regimental headquarters. The ammunition was delivered to his company on time. Comrade Ovcharenko continues his combat service, promoted to a machine gunner."
Edit: I have found the full text of the award order!
Ovcharenko was recommended for the Hero of the Soviet Union medal, combined with the Order of Lenin.