The 2S7 Pion ("peony") was a Soviet self-propelled 203 mm cannon under the GRAU designation 2S7 and called "Pion" or "Peony" as customary flower names were given to this category of ground vehicles. This was when introduced in 1976 the longest ranged conventional self propelled artillery anywhere. Its 203 mm 2A44 gun L/56.2 could reach a target at 37.4 km with the 43.2 kg 3VOF34 round. It was produced until the collapse of the Soviet Union and authors still argues about the number delivered (as no record was established to confuse the west), with numbers ranging from a mere 250 to 500, or even 1,000 units*. Russian wikipedia states 468+. They were exported to Belarus, Czechoslovakia, Poland, now Slovakia and are also used today by Angola, Azerbaijan, Georgia, Ukraine having 99, brought from reserve and restored to be sent in Donbass. Russia still have 60 of the later 2S7M version in active service today with 260 older 2S7 in reserve by 2022. They were to be modernized from December 2021.

An much improved version of the "Peony"

Under NATO "M1975" The 2S7 Pion (Project 216) was also designated officially SO-203 and sued a chassis, partly based on the T-72 and T-80 main battle tanks. The centerpiece of the design was a massive 2A44 203 mm gun hinged with its base at the hull rear, unprotected (no turret). The vehicle was capable of self-entrenching and used an overpressure CBRN defense system. The massive gun had an estimated service life of 450 rounds. Chassis was produced at the Kirov Factory in St. Petersburg and the gun and mount at Titan-Barrikady, Volgograd.

As of 1990, the cost of one 2S7 self-propelled gun was 521,527 rubles. In total, over 500 2S7 were produced over 16 years, including the 27M.

However in 1982 it was already believed the design could be improved, which led to the creation of the improved "M" version. So many improvements were made that even called 2S7M, a new name was chosen, "Malka", also called Project 207M. This was a full-on modernization, with a Project 216M chassis powered by a V-84B diesel engine, new guidance and loading systems, sometimes also called "Pion-M". Production of the standard 2S7 ended in 1985 and of the 2S7M started in 1986.

Design Changes

The need to modernize the 2S7 self-propelled gun led research and development work under the program "Malka" (GRAU 2S7M) starting with a new engine, the V-84B, which had an different engine layout close to the transmission compartment. The new engine was more tolerant and could be refueled not only with diesel but also kerosene and gasoline. The chassis was also modernized, with reworked suspensions and shock absorbers albeit the tracks and roadwheels remained the same.

In February 1985 the new Malka underwent testing. Its service life was increased to 8,000-10,000 km. There was a new display for the chief officer while gunner and commander's positions received digital indicators with automatic data reception to reduce the time spent from the traveling to combat position and back. The stowage was reworked and the round capacity doubled, which at least enough ammunition to do some impression. A battery of four vehicles was now capable of sending collectively 32 rounds at a target before retreating to a safe resupply point.

The new gun laying and loading system also allowed to load the gun at any angle, considerably increasing the rate of fire by 1.6 times (up to 2.5 rounds per minute) and the fire mode by 1.25 times. To monitor subsystems, it was equipped with routine control equipment continuously monitored the general state of the weapon, the diesel parameters, transmission, hydraulic system and auxiliary power unit. The crew was reduced to six.

The 2s7M comes with an R-173 communications complex, and can carry eight 203 mm shells with the gearing and loading mechanisms revised to increase the rate of fire from 1.5 to 2.5 rds/min. More automation also reduced the crew, and the vehicle is easier to prepare, from travel to fire ready, and much faster to pack up and leave. The added weight is compensated by the better diesel engine, for a bit of extra speed of 50+ kph.

By the late 1970s, there was also a project for a naval artillery mount as "Pion-M", developed from the 2A44 cannon with a weight of 65-70 tons. This was notably envisioned for the new Sovremenny class (Project 956) artillery destroyers but never implemented. The ammunition supply, was to be 75 rounds, at 1.5 rounds per minute. However, due to the fundamental disagreement of the Navy leadership the fnal destroye design changed and the program was cancelled.

The differences between the two could be summarized on a simple table:

2S7 vs. 2S7M
Start of production	1975	1986
Combat weight	45t	46.5t
Crew	7	6
Main gun	2A44	2A44
Ammunition	4	8
Maximum rate of fire	1.5	2.5
Regular rate of fire/h	40	50
Travel to Fire ready	10 min.	7 min.
Time to travel config.	10 min.	5 min.
Engine	V-46-1 780 hp	V-84B 840 hp
Radio set	R-123M	R-173
Intercom	1V116	1V116

Current status

The 2S7M saw action in Ukraine recently. According to Oryx, so far Russia lost thirty-one 2S7 or 27SM. Ukraine lost thirteen, all 2S7 vehicles, as seemingly Ukraine does not possess the Malka variant. These were former vehicle in reserve, dusted off and restored to combat conditions. They are of course less efficient than the Russian Malka.

specifications
Dimensions (L-w-h)	as 2S7
Total weight, battle ready	46,5 tonnes (102,500 lb)
Crew	6, but up to 14
Propulsion	V-84B V12 turbocharged diesel 840 hp
Speed	50 km/h (31 mph)
Range	650 km (400 mi) on flat
Armament	203 mm 2A44 gun L/56.2
Armor	10 mm (0.39 in)
Total production	c150 1986-1990

Illustrations

2S7M in Russian service, 2000

A Russian 27M Malka in 2022

An opposing Ukrainian 2S7 Peony, 2023

Gallery

Videos

Sources

Jane's Armour and Artillery 2005-2006
mil.in.ua
en.defence-ua.com/
recomonkey.com
On nationalinterest.org
armyrecognition.com analysis upgrade
pmulcahy.com
theworldwars.net/
/old.weaponsystems.net
armyrecognition.com
weaponsystems.net