After the beginning of the war, the Mytischi Machine Building Plant received a government assignment for the production of military products and was transferred to the People's Commissariat of Armaments. The manufacture of bodies for air bombs and shells, platforms for antiaircraft artillery systems began. Despite daily air raids, the plant did not interrupt the production schedule for an hour, worked in two shifts.

October 10, 1941, it was decided to evacuate the Mytishchi plant in the Urals. October 17 from the station Mytishchi went to the Urals, the first echelon with plant equipment and heated freight cars, with workers inside.

Meanwhile, the Moscow Regional Committee of the All-Union Communist Party (Bolsheviks) adopted a decision: to use free production facilities remaining after the evacuation  for the manufacturing of armored turrets, antitank "hedgehogs", and to organize the production of grenades, shells and the repair of military equipment At the same time, the plant remained without equipment, materials, fuel and labor. But thanks to the selfless work of the deputy director of the plant, D. F. Pankratov, the head of the mechanical workshop S. N. Markov and others in the beginning of November, one shop was already ready for work.

At the same time, other workshops were being prepared. People worked days and nights in cold buildings, the machines worked continuously. During the first month, the plant cast 18 armored turrets with 4.5 tons each, and prepared over 110,000 bodies for anti-tank grenades. At the end of November, the plant began punching mortar support plates and assembling anti-aircraft armored trains. Workers carried out the labor order, despite all the difficulties, without having any drawings or workpieces.

In March 1942, the plant began the production of shells and separate parts for rockets. April 21, 1942 GKO USSR decided to return the evacuated equipment. In the same year, the design bureau (now OKB-40) was established at the enterprise and serial production of self-propelled artillery units SAU-76 was set up, and the plant itself was renamed into plant No. 40.

In 1945, the plant mastered the production of new self-propelled units with quadruple antiaircraft machine guns, and then powerful caterpillar tractors.

For exemplary performance of assignments for the front, the plant was awarded the Order of the Patriotic War of the first degree.