The 2S7 "Pion" (translated to English as "Peony", M-1975 is NATO classification) is a Soviet 203 mm self-propelled gun capable of firing nuclear ammunition. It was accepted for service in the Soviet Army in 1975 as a self-propelled gun of the Reserve of Supreme Command of the USSR. 2S7 was designed for suppression of enemy's back lands, elimination of objects of strategic importance and means of nuclear attack from the range up to 47 km.
Its design is based on a T-80 chassis carrying an externally mounted 2A44 203 mm gun on the hull rear. It takes the crew of seven men 5–6 minutes to come into action and 3–5 minutes to come out of action. It carries four 203 mm projectiles for immediate use. The range of the gun can be extended to 55 km by using RAPs (Rocket Assisted Projectiles). The Pion has been the most powerful conventional artillery piece since entering service in 1983. One interesting feature of the Pion is the firing alarm. Because the blast of the weapon firing is so powerful - it can physically incapacitate an unprepared soldier or crew member near it from concussive force - the Pion is equipped with an audible firing alarm that emits a series of short warning tones for approximately five seconds prior to the charge being fired.
The 2S7 carries a crew of 14, of these 7 are carried by the Pion and the remaining 7 are accompanied by an auxiliary vehicle. The system carries 4 total round with additional 4 being carried by the support vehicle. Due to the long range the crew can fire one or two rounds and leave position before the first round is able to hit the enemy position over 40km away, thus avoiding being susceptible to possible return fire. The 2S7 was modernized in 1983 and named 2S7M 'Malka'. The new vehicle can be distinguished from the original item by new more powerful multi diesel engine, increased permanent ammunition (8 rounds vs 4 in original version), higher fire rate and new fire control system. Despite of the fact that no official figures on 2S7 production have been released, it is estimated that from 500 to 1000 were built during 1975-1990 years. Ukraine is a second largest operator of 'Pion's having a bit less than 100 items in 2014, while Russia is on the first place (320 units as of 2014) however 300 of them are in stock. Ukrainian vehicles were also kept in stand-by storage before the military conflict in the east of Ukraine. After first Minsk Agreement in September 2014 (Minsk-1) Ukraine start actively using Pions as were able to fire outside of 'buffer zone. In the end of January 2015 Ukrainian Ministry of Defense claimed that separatists received a number of 2S7s from Russia. The convoy of 'Pion's was noticed in Makeyevka on January 29th, 2015.