The SU-14 was a prototype Soviet heavy self-propelled gun built on a T-35 chassis. The original prototype mounted a 152 mm gun M1935 (Br-2); the SU-14-1 variant of 1936 carried a 203 mm gun B-4 which could fire 48.9 kilogram shells at ranges up to 25 km. Its armour was 20 to 50 mm thick. It never entered serial production.