While serving as a tank commander, Kalashnikov was seriously wounded in the Battle of Bryansk during Operation Barbarossa. This injury forced him to be evacuated to a hospital for recovery.

While recuperating in the hospital, Kalashnikov overheard fellow soldiers complaining about the Soviet Red Army's inferior weaponry compared to the Germans. This inspired him to design a better submachine gun, using the hospital's workshops and the knowledge he gathered.

Kalashnikov presented his first submachine gun design to the Main Artillery Directorate (GAU) in 1942. While not adopted for mass production, it earned him recognition and led to his assignment to the Central Scientific-testing Range for rifle firearms (NIPSMVO).

Kalashnikov designed a gas-operated carbine for the new 7.62x39mm cartridge. Although it was not accepted into service, it provided valuble experience and knowledge to build on.

The Soviet Union initiated a competition to develop a new assault rifle firing the 7.62x39mm cartridge, prompted by the German StG 44. Kalashnikov joined the competition.

Kalashnikov designed the AK-46 prototype assault rifle, which entered into the trials for the new Soviet assault rifle.

After undergoing rigorous testing and modifications, the AK-47 (Avtomat Kalashnikova 1947) was officially adopted by the Soviet Army. This marked a turning point in Kalashnikov's career and the beginning of the AK-47's global impact.