122 mm gun M1931 / 37 ( A - 19 ) 122 mm corps gun M1931 / 37 ( A - 19 ) ( ) was a Soviet field gun developed in late 1930s by combining the barrel of the 122 mm gun M1931 ( A - 19 ) and the carriage of the 152 mm howitzer - gun M1937 ( ML - 20 ) . The gun was in production from 1939 until 1946 . It saw action in World War II ( primarily with corps and RVGK artillery of the Red Army ) and remained in service for a long time after the end of the war . Vehicle - mounted variants of the gun were fitted to the IS - 2 and 3 tanks and ISU - 122 self - propelled gun . Development history . In 1936 the Red Army adopted the 122 mm gun M1931 , also known as A - 19 . Unlike earlier ordnance pieces used by the Red Army , it had split trail carriage with suspension , and consequently improved mobility and traverse . The carriage of M1931 had a number of shortcomings though . The elevation mechanism was slow and unreliable ; solid - tired wheels hindered mobility to some extent ; there were technological problems in carriage production . Soon after the M1931 , the Red Army received another artillery piece in form of the 152 mm howitzer - gun M1937 ( ML - 20 ) , developed at the No . 172 Plant , under F . F . Petrov . This led to an upgrade of the M1931 , handled also by Petrov ' s design bureau . The barrel of the M1931 was placed on the carriage of a ML - 20 . The improved gun successfully underwent trials in September – October 1938 and on 29 April 1939 was adopted as 122 mm corps gun M1931 / 37 . Unusually , the new variant , like the old one , was referred to as A - 19 . Production history . The M1931 / 37 was manufactured by the " Barrikady Plant " in Stalingrad ( 1939 – 41 ) , " No . 172 Plant " ( 1941 – 46 ) . The number of M1931 / 37s manufactured can be estimated at about 2 , 450 , not including vehicle - mounted barrels . Description . Like barrel of late production M1931 , the barrel of the M1931 / 37 was of loose liner construction , and consisted of liner , jacket and screwed - upon breech . The breechblock was of interrupted screw type , similar in construction to that of the 152 mm howitzer M1910 / 37 . Recoil system consisted of hydraulic recoil buffer and hydropneumatic recuperator , both located inside the cradle under the barrel . The gun had split trail carriage adapted from the 152 mm howitzer - gun M1937 ( ML - 20 ) . The carriage was fitted with leaf spring suspension and metal wheels with pneumatic tire s . The carriage also featured equlibrator . The shield gave the crew some protection from small arms and shell fragments . The M1931 / 37 was transported as a single piece , with barrel pulled back . It was permitted to tow the gun with barrel in its normal position , but for short distances only and with speed of no more than 4 – 5 km / h . Several types of artillery tractor s were used : S - 2 Stalinets - 2 , Komintern and , from 1943 , Ya - 12 . Organization and employment . Both variants - M1931 and M1931 / 37 - had the same place in army organizations , were often used alongside each other and combat reports rarely differentiate between them ; consequently , the data in this section is for M1931 and M1931 / 37 together , unless specified otherwise . Red Army . The A - 19 was originally intended for corps artillery . Together with ML - 20 it formed a so - called " corps duplex " . In 1940 - 41 there were three types of corps artillery regiment s : Soon after the outbreak of the Great Patriotic War the corps artillery was eliminated ( as rifle corps themselves were eliminated ) and was only reintroduced late in the war . Those new artillery regiments were issued 122 mm guns along with other pieces , mainly 107 mm guns and 152 mm howitzers , in total 16 - 20 pieces per regiment . On 1 June 1944 , RKKA corps artillery possessed 387 A - 19s ( along with some 750 107 mm and 152 mm pieces ) , an on 1 May 1945 - 289 A - 19s ( again along with some 750 100 mm , 107 mm and 152 mm pieces ) . The gun was also used by artillery units of the Reserve of the Main Command ( RVGK ) . In mid - 1941 a cannon regiment of the RVGK had 48 A - 19 ; in autumn 1941 these regiments were reorganized , a new , smaller , regiment had 18 A - 19s . From 1942 cannon brigade s were introduced , with 36 A - 19s each . Such brigade could be a part of an artillery division - a huge formation , with up to four brigades of A - 19 or ML - 20 ( meaning up to 144 pieces ) . The first combat use of the A - 19 was in the Battle of Khalkhin Gol . It also saw combat in the Winter War . On 1 March 1940 there were 130 A - 19 guns at the frontline . Three pieces were lost . By June 1941 the RKKA possessed , according to different sources , 1257 ( 1236 in the Army and 21 in the Navy ) or 1300 A - 19s . The gun proceeded to be used throughout the Great Patriotic War . The A - 19 was primarily used for indirect fire against enemy personnel , fortification s and key objects in the near rear . It was also equipped with armour - piercing shells for direct fire against armoured targets . Although not an ideal anti - tank gun because of its large size , slow traverse and relatively slow rate of fire , in 1943 the A - 19 was one of only a few Soviet guns effective against the new German tanks , such as the Tiger and Elefant . It is said that an A - 19 was the first gun to fire at the start of the Battle of Berlin . Other operators . In the early stage of the Great Patriotic War hundreds of A - 19s fell into the hands of Wehrmacht . Both variants were adopted - M1931 as 12 , 2 cm K . 390 / 1 ( r ) and M1931 / 37 as 12 , 2 cm K . 390 / 2 ( r ) . Germans used a total of 424 of these guns in field and coastal artillery and manufactured ammunition for them . The Finnish Army captured 25 pieces in 1941 and also pressed them into service . The same designation 122 K / 31 was applied to both variants . Because of shortage in heavy tractors , the gun was mostly used in coastal artillery . Four pieces were lost ; the rest remained in service after the war . In 1980s some pieces had their barrels replaced with 152 mm barrels of ML - 20 ; the resulting pieces were designated 152 H 37 - 31 . In late 1980s both 152 H 37 - 31 and the remaining 122 K / 31 received new 152 mm L / 32 barrels manufactured by Vammas , to become 152 H 88 - 31 . Only in 2007 the Finnish Army began to remove these guns from service . The A - 19s were used by Polish Armed Forces in the East in 1944 - 45 and remained in Polish service after the war . In 1952 the Polish Army possessed 63 pieces . In 1980s , in order to improve their mobility , the Polish guns were fitted with wheels from KrAZ - 255B truck , resulting in 122 mm armata wz . 1931 / 37 / 85 . By 2004 the guns were removed from service . 78 122 mm guns were supplied to Yugoslavia . Other recipients of the M1931 / 37 were Syria ( at least 100 pieces , currently in storage ) and Egypt . China also purchased a number of the M1931 / 37 during early stages of the Second Sino - Japanese War . Ammunition . The gun fired separate loading , cased charge ammunition , with one of four possible propellant charges - the full , no . 1 , no . 2 and no . 3 ( the smallest ) . In addition to 122 mm gun shells , the A - 19 could fire 122 mm howitzer shells ; however because of lesser durability of those shells they could not be used with full charge . Surviving pieces . The M1931 / 37 can be seen , among other places :