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
regiments: • With two
battalions of ML-20 and one of either A-19 or 107-mm guns (a total of 24 ML-20s). • With two battalions of ML-20 and two of either A-19 or 107-mm guns (a total of 24 ML-20s). • With three battalions of ML-20 (a total of 36 ML-20s). 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), and 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
brigades 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,
fortifications 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. The Tank gun variant, the D-25 was even able to penetrate the upper frontal plate of the
Tiger II at a range of 500-600 metres although it did require multiple rounds to be fired to do so.
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. Germany sold 150 of the captured A-19s to Spain in 1943. This transaction was part of the "Bär Program", a program to complete and modernize the equipment of the
Spanish Armed Forces using armament delivered by Germany. Most of these A-19 were assigned to the Corps Field Artillery Regiments of the
Spanish Army, each regiment receiving 12 pieces to equip a group. The model was well liked in Spain, and 32 additional pieces were ordered by the Army and produced – with neither documentation nor licenses – by the Trubia Arms Factory. After acquisition of more modern American artillery, the Spanish A-19s were relegated to the artillery regiments of territorial defense units. 173 of the Spanish A-19s were modernized in the 1970s, and the guns remained in service with the Spanish Army until the 1990s. 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. The
Kingdom of Romania captured in 1941 a number of 477 various types of 122 mm howitzers and guns including M1931/37 and the modern ones were used as divisional artillery for units rebuilt after 1941 campaign. Some guns captured by the Romanians were modified and fitted on the initial prototypes of the
Mareșal tank destroyer. 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.
Yugoslavia received 78 122 mm guns. The
People's Army of Vietnam also received A-19s and used them during the
Vietnam War. Other recipients of the M1931/37 were
Syria (at least 100 pieces in storage ) and Egypt. China also purchased a number of the M1931/37 during early stages of the
Second Sino-Japanese War. ==Variants==