The Mig-3 entered service with the Soviet Air Force in 1940. It was a highly capable fighter, and though slightly out-gunned by other fighters of the time, it was used successfully in large numbers. Production was stopped by the discontinuation of engines by Mikulin to concentrate on the IL-2.
The Mig-3 was armed with 1 x 12.7mm, and 2 x 7.62mm machine guns. It was also adapted to carry bombs and rockets, but was not suited to the ground attack role.