122 mm gun M1931 ( A - 19 ) 122 mm corps gun M1931 ( A - 19 ) ( ) was a Soviet field gun , developed in late 1920s and early 1930s . In 1939 the gun was replaced in production by an improved variant , M1931 / 37 . The piece saw action in World War II with the Red Army . Captured guns were employed by Wehrmacht and the Finnish Army . Development history . From late 1920s the Red Army sought to upgrade its First World War era artillery pieces . In January 1927 the Main Artillery Directorate ( GRAU ) initiated development of a new 122 mm gun for corps artillery . The development was initially entrusted to GRAU design bureau ( led by F . F . Lender until its death in September 1927 ) , and from June 1929 - to the design bureau of All - Union Ordnance Trust , with assistance from GRAU designers . On 17 June 1929 a prototype piece , along with technological documentation , was ordered from Motovilikha Plants . The piece underwent trials starting in October 1931 , with two barrels of different construction , both fitted with muzzle brake . In May 1932 the gun was sent for improvements to the " No 38 Plant " , and it received that plant ' s designation " A - 19 " . In 1933 , three more prototypes were ordered from the Barrikady Plant in Stalingrad and were completed in March 1935 . The gun reached trials again in November 1935 . After successfully completing the trials , it was adopted by RKKA on 13 March 1936 as 122 mm corps gun M1931 ( A - 19 ) . Production history . The M1931 was in production in 1935 - 1939 . It was gradually improved until 1937 , so late production peces differ from the early production ones . In 1939 , the gun was replaced in production by an improved variant , M1931 / 37 , which combined barrel of the M1931 with the carriage of the 152 mm howitzer - gun M1937 ( ML - 20 ) . The exact number of pieces manufactured is not known ; estimations are 450 - 500 pieces . Description . In contrast with World War I - era guns , the M1931 had split trail carriage , allowing for much wider traverse angle . The carriage was fitted with leaf spring suspension and ten - spoke metal wheels with solid rubber tire s . Some late production pieces had ML - 20 - type wheels with pneumatic tires . The carriage also featured spring - type equlibrator . The shield gave the crew some protection from small arms and shell fragments . The barrel consisted of liner , jacket and screwed - upon breech . Early production barrels hade built - up construction , but in 1936 these were replaced in production by free liner barrels . The breechblock was of interrupted screw type , similar in construction to that of the 152 mm howitzer M1910 / 37 . Unlike early prototypes , productional barrels did not have muzzle brake . Recoil system consisted of hydraulic recoil buffer and hydropneumatic recuperator , both located inside the cradle under the barrel . The limber of the experimental 152 mm ML - 15 was used . Initially a separate transportation ( with the barrel removed from the carriage and transported on a special wagon ) was considered . However , following the trials it was decided to always tow the gun as a single piece . Several types of artillery tractor s were employed : 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 a few guns effective against new German tanks . 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 . Variants . As mentioned above , late production M1931s differed from early production ones . Guns manufactured starting in 1936 had free liner barrel construction in contrast to the earlier built - up barrels ; in 1937 changes in breech block construction were introduced , and some late production pieces received ML - 20 - type wheels with pneumatic tires . In addition , the M1931 had a number of experimental variants . In 1933 , development of a carriage with improved off - road mobility was started . The carriage in two variants - on tracks and on large , tractor - type wheels - reached trials in 1937 and was found to be not durable enough . In 1933 - 36 the gun was involved in experiments with pre - rifled projectiles . For these experiments a special variant of the barrel was produced . The experiments were stopped because of inherent deficients of those projectiles , namely more complicated loading process and lower accuracy . Another variant , with bag loading , designated Br - 3 , reached trials in 1937 , but was not adopted . The carriage of M1931 , almost unmodified , was used for the 152 mm gun M1910 / 34 . As already mentioned , in Finland carriages of the A - 19 were fitted with 152 mm barrels , resulting in two models : Summary . The M1931 was one of the first Soviet artillery pieces to feature split trail carriage . This carriage construction allowed for much better traverse angles compared to earlier single trail or box trail carriages . Good elevation angle and ability to use different propellant charges made the gun flexible indirect fire weapon , and its ballistics were powerful enough to make it useful in direct fire role against enemy armor ( though , as mentioned above , it was not an ideal anti - tank gun because of its size , traverse speed and rate of fire ) . 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 . These shortcomings eventually led to adopting a better carriage , creating the M1931 / 37 . As calibers similar to 122 mm were not typical for western field artillery of World War II era , pieces directly comparable to the M1931 were rare . The German 10 . 5 cm sK 18 was significantly lighter ( 5 . 64 t ) while having about the same range ( 19 km ) , but fired much smaller 15 kg shell ; on the other side , the 15 cm K 18 was heavy ( combat weight 12 . 46 t ) , limited production ( 101 pieces ) weapon , more comparable to the Soviet 152 mm Br - 2 . Late in the war Germans worked on a number of 128 mm field guns ; one of these designs , the 12 . 8 cm K 81 / 2 , was a gun with combat weight of 8 . 2 t , based on a heavily modified carriage of captured 152 mm ML - 20 . However , little is known about its characteristics ; anyway , none of these 128 mm designs reached mass production . British Army and U . S . Army both employed 4 . 5 inch ( 114 mm ) pieces with similar characteristics , and designed to utilize the same ammunition - BL 4 . 5 inch Medium Field Gun and 4 . 5 inch Gun M1 respectively . The 5 . 65 - ton M1 fired a 24 . 9 kg shell to the maximum range of 19 . 3 km ; however the only type of ammunition available for the gun was a HE - frag shell , and that contained only about two kg of explosives . 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 ; use of steely iron howitzer shells O - 460A and O - 462A was prohibited . Surviving pieces . The M1931 can be seen :