During the Winter War with Finland in 1940, Soviet troops were first used heavy artillery to break through heavily fortified enemy defenses. Mannerheim Line is a continuous series of reinforced concrete structures, which housed cannons and machine guns. To pave the way for advancing infantry, 203-mm howitzer B-4 showered thousands of enemy shells. Their breaks on the domes bunkers led to the fact that the defenders burst eardrums and walked nosebleed. Prisoners with respect Finns called B-4 howitzer Stalinist sledgehammer.
Development tools began in 1927 in KB Artkomiteta GAC. Work initially headed FF Lender, and then project management was taken over by the leading designers of the plant. The first prototype was made howitzers in early 1931, and mass production of artillery systems deployed in the next year. 203-mm gun was meant to destroy the enemy's high-strength structures of reinforced concrete and steel armor, as well as to destroy targets located away from the front line.
Howitzer B-4 was attached to, or monobloc barrel liner and heavy carriage to the track progress. Carriage has high maneuverability and can fire from the ground without the use of stops and platforms. In the stowed position weapon disassembled into two parts (barrel and carriage) and transported on two wagons at a speed of about 15 km / h Ammunition B-4 consisted of rounds of separate loading kartuznogo with ten different charges. Shots were fired high-explosive shells and betonoboynymi weighing about 100 kg. To facilitate loading at the rear of the howitzer was mounted winch.
the beginning of World War 33 heavy artillery regiments RGC was 727 howitzers B-4. Small number of them captured by the Germans. The rest were assigned to the rear and took part in combat operations until the end of 1942, when Soviet troops attacked.