BT-42. Finland captured more than fifty BT-7s during the Winter War. Since the BT-7 gun was inadequate, several were modified into assault guns using an improvised turret and surplus British 4.5 inch howitzers. The BT-42 was used in the Continuation war, where it proved adequate as an assault gun, but virtually useless against Soviet T-34s. They were replaced by German made StuG IIIs.