The Soviet Union's first assault gun to be produced was a machine armed with a 122 mm howitzer called the SU-122. It was designed by engineer E.W. Wilniszczikov with the assistance of F.F. Pietrov, the king of Russian gun designers, who had designed the 122 mm gun. This was an excellent howitzer with a range of 11,800 m, muzzle velocity of 515 m/sec and rate of fire of 5 or 6 rounds/min. The SU-122 self propelled gun was similar in shape to the German StuG III armed with the short barreled 75 mm gun. With its bulky recoil mechanism and mantlet, the first production SU-122 was quite unsightly. The final production model, however, featured refined semi spherical recoil mechanism and gun shield. The SU-122 assault gun first saw action in the Battle of Kursk in the summer of 1943. SU-122s took part in the recapture of Orel to the north of Kursk and in the subsequent pursuit.