During WWII, Finnish forces were very short of adequate armored vehicles such as tanks. Most of the tanks in their possession were obsolete models which were no match for the newer Russian tanks such as the T-34 and KV-1. However, circumstances meant the Finnish Army had to make the most of what was available, and they combined the hull from a captured Russian BT-7 light tank with a new turret armed with the ancient 1918 British 4.5-inch howitzer to create the BT-42 assault gun. It is believed only 18 vehicles were produced during the WWII conflict.