The LaGG-3 of the 4th series was the second production modification of the aircraft and differed from earlier versions mainly in its armament. The problem of installing the ShVAK cannon firing through the propeller hub was solved, and underwing mounts for rockets and bombs were added (when four RS rockets were carried, only one bomb could be mounted). Due to a shortage of heavy machine guns, the aircraft retained a single synchronized Berezin BS machine gun. The 4th series received the improved Klimov M-105PA engine, equal in power to the M-105P but fitted with the more advanced K-105BS carburetor. Structural changes to the fuselage were also introduced. Heavily armed and highly survivable, the LaGG-3 proved effective against bombers and as a ground-attack aircraft. In skilled hands it could also fight fighters: on February 3, 1942, A. A. Gubanov shot down three Bf 109s in one battle.
More to read about the KIT here, thanks to scalemates, a Belgian Scale modeling database