S-51 Heavy SPG

The heavy C-51 SPG was designed at the end of 1943 at the CADB under the leadership of V.G.Grabin. In order to obtain a powerful mobile fire weapon, the designers installed a 203-mm howitzer B-4 on the body of a heavy tank KV-1S. The result was not very successful and after the tests in early 1944 the project was closed.