122 mm gun M1931 (A-19)

From the 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.[1]

On 17 June 1929 a prototype, along with technological documentation, was ordered from Motovilikha Plants. It 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).[1]

The M1931 was in production in 1935-1939. It was gradually improved until 1937, so late production pieces 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.

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 tires. Some late production pieces had ML-20-type wheels with pneumatic tires. The carriage also featured spring-type equilibrator. The Gun 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 had a built-up construction, but in 1936 these were replaced in production by loose 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 hydro-pneumatic recuperator, both located inside the cradle under the barrel.

The limber of the experimental 152 mm ML-15 was used.[1]

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 tractors were employed: S-2 Stalinets-2, Komintern and, from 1943, Ya-12.

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.

M1931 in the Central Armed Forces Museum, Moscow. Note ML-20-type wheels.

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.[1]

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.[1]

Another variant, with bag loading, designated Br-3, reached trials in 1937, but was not adopted.[1]

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:

• 152 H 37-31 - with barrel of the Soviet ML-20,
• 152 H 88-31 - with 152 mm L/32 barrels manufactured by Vammas.

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.[1] 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.

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).[1] 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.[9]

M1931 in the Museum of Artillery and Engineering Forces, St. Petersburg.

The M1931 can be seen:

• In the Central Armed Forces Museum, Moscow, Russia.
• In the Museum of Artillery and Engineering Forces, Saint Petersburg, Russia.
• In the Artillery Museum in Hämeenlinna, Finland.

Wikimedia Commons has media related to 122-mm corps gun M1931.

• Shirokorad A. B. - Encyclopedia of the Soviet Artillery - Mn. Harvest, 2000 (Широкорад А. Б. Энциклопедия отечественной артиллерии. — Мн.: Харвест, 2000., ISBN 985-433-703-0)
• Shirokorad A. B. - The God of War of The Third Reich - M. AST, 2002 (Широкорад А. Б. - Бог войны Третьего рейха. — М.,ООО Издательство АСТ, 2002., ISBN 5-17-015302-3)
• Ivanov A. - Artillery of the USSR in Second World War - SPb Neva, 2003 (Иванов А. - Артиллерия СССР во Второй Мировой войне. — СПб., Издательский дом Нева, 2003., ISBN 5-7654-2731-6)
• Kolomiets M. - The Battle of River Khalkhin-Gol - "Frontovaya Illustratsiya" magazine, no. 2, 2002 (М.Коломиец. - Бои у реки Халхин-Гол. - журнал «Фронтовая иллюстрация», №2, 2002)
• Military History Journal, no. 5, 2005 and no. 2, 2006.
• Statistical Compilation No 1 - Red Army on 22 June 1941.
• Ballistic Tables for Corps Guns M1931 and M1931/37 - Voenizdat NKO, 1944.
• 122 K/31 at Jaegerplatoon.net

• Photo gallery at svsm.org
• Walk-around of A-19