on the first batch, the SU-85's observational optics were improved by the introduction of a standard commander's cupola - the same as on the T-34/76 model 1942 - in addition to the already existing prismatic observation sights installed in left side and rear. On later vehicles, the same optics were added, allowing all-around observation. Production history SU-85 production started in mid-1943, with the first vehicles reaching their units by August. When the up-gunned T-34-85 medium tank entered mass production in the spring of 1944, there was no point in continuing production of a tank destroyer without superior firepower. In light of this, SU-85 production was stopped in late 1944 after 2,650 vehicles had been produced. It was replaced on the production lines by the SU-100 tank destroyer, armed with the more powerful 100 mm D-10S gun, but due to delays with 100 mm ammo, a stopgap version called SU-85M appeared in September 1944, which was SU-100 fitted with 85 mm gun, already with thicker frontal armor and commander's cupola. Service history The SU-85 entered combat in August 1943. It saw active service across the Eastern Front until the end of the war. Though a capable weapon, it was found that its 85 mm weapon was not adequate to penetrate the armour of the larger German armoured fighting vehicles. It was replaced by the SU-100. The SU-85 was withdrawn from Soviet service soon after the war, and was exported to many Soviet client states in Europe and elsewhere. Some SU-85s were converted to use as command and recovery vehicles. Countries such as North Korea and Vietnam kept it in service for many years. Variants Former Soviet Union SU-85 Basic version with four periscopes and no commander's cupola. SU-85M SU-100-like cupola and thicker frontal armor. 315 built. Poland WPT-34 (1960s) - Polish repair and maintenance vehicle with a superstructure replacing the casemate, a crane, a large-diameter telescoping snorkel for deep fording operations as well as a large-spade type earth anchor in the rear. It was converted from SU-85 tank destroyers as well as T-34 medium tanks and SU-100 tank destroyers. Operators – 26 armored recovery vehicles based on the SU-85 were received by 1 January 1956 from 1952/56 until 1962 See also List of Soviet tanks - covers all periods ASU-85 SU-100 Tanks of comparable role, performance and era Germany – StuG III, StuG IV and Jagdpanzer IV Italy – Semovente da