152 mm gun M1935 (Br-2)
Encyclopedia
152 mm gun M1935 () was a Soviet
Red Army
The Workers' and Peasants' Red Army started out as the Soviet Union's revolutionary communist combat groups during the Russian Civil War of 1918-1922. It grew into the national army of the Soviet Union. By the 1930s the Red Army was among the largest armies in history.The "Red Army" name refers to...

 152.4 mm heavy gun, produced in limited numbers by the Barrikady Plant in Stalingrad in late 1930s. The most unusual feature of the gun was its tracked carriage, shared by a number of Soviet heavy artillery systems of the interwar period. Despite a number of drawbacks, most notably limited mobility and short service life of the barrel, the weapon was employed throughout the German-Soviet War; an upgraded variant with wheeled carriage, Br-2M, remained in service at least until 1970s.

B-10

Work on a long range 152 mm gun for Reserve of the Main Command units started in 1929, when the Bolshevik Plant
Obukhov State Plant
Obukhov State Plant is a major Russian metallurgy and heavy machine-building plant in St. Petersburg, Russia. It was founded in 1863 to produce naval artillery based on German designs by Krupp. It has since been a major producer of artillery and other military equipment. From 1922 to 1992 it...

 in Saint Petersburg
Saint Petersburg
Saint Petersburg is a city and a federal subject of Russia located on the Neva River at the head of the Gulf of Finland on the Baltic Sea...

 received from the Artillery Directorate requirements specifications for such a piece. The project received a factory index B-10. First barrel was manufactured in April 1932; it was sent for trials even before the carriage, which had an unusual tracked
Caterpillar track
Continuous tracks or caterpillar tracks are a system of vehicle propulsion in which modular metal plates linked into a continuous band are driven by two or more wheels...

 construction, was ready. Development and testing of the B-10 continued until 1935; a number of problems were revealed, including slow elevation, low rate of fire and short service life. As a result, the gun was not adopted. The two produced barrels
Gun barrel
A gun barrel is the tube, usually metal, through which a controlled explosion or rapid expansion of gases are released in order to propel a projectile out of the end at a high velocity....

 were experimentally modified for firing pre-rifled
Rifling
Rifling is the process of making helical grooves in the barrel of a gun or firearm, which imparts a spin to a projectile around its long axis...

 projectiles and polygonal projectiles respectively. The experiments didn't produce practical results. An attempt to improve elevation speed by use of an electric motor
Electric motor
An electric motor converts electrical energy into mechanical energy.Most electric motors operate through the interaction of magnetic fields and current-carrying conductors to generate force...

 failed to provide smooth elevation. The Soviet Navy
Soviet Navy
The Soviet Navy was the naval arm of the Soviet Armed Forces. Often referred to as the Red Fleet, the Soviet Navy would have played an instrumental role in a Warsaw Pact war with NATO, where it would have attempted to prevent naval convoys from bringing reinforcements across the Atlantic Ocean...

 briefly considered adopting a derived weapon as a coastal gun
Coastal artillery
Coastal artillery is the branch of armed forces concerned with operating anti-ship artillery or fixed gun batteries in coastal fortifications....

, in towed or self propelled variant, the latter based on T-28
T-28
The Soviet T-28 was among the world's first medium tanks. The prototype was completed in 1931 and production began in late 1932. It was an infantry-support tank intended to break through fortified defences...

 medium tank chassis. Only the towed variant, B-25, reached factory trials; eventually it was canceled because of shortcomings of the design and decision of the Army not to adopt the B-10.

B-30 and Br-2

In early 1930s the Artillery Directorate ordered a development of a "heavy artillery triplex", consisting of a 152 mm gun, a 203 mm howitzer
Howitzer
A howitzer is a type of artillery piece characterized by a relatively short barrel and the use of comparatively small propellant charges to propel projectiles at relatively high trajectories, with a steep angle of descent...

 and a 280 mm mortar utilizing the same carriage. The Bolshevik Plant and the Barrikady Plant in Stalingrad were entrusted with the development. The 152 mm gun projects were called B-30 (sometimes referred to as B-10-2-30) and Br-2 respectively. Both mated a barrel ballistically
Ballistics
Ballistics is the science of mechanics that deals with the flight, behavior, and effects of projectiles, especially bullets, gravity bombs, rockets, or the like; the science or art of designing and accelerating projectiles so as to achieve a desired performance.A ballistic body is a body which is...

 identical to that of the B-10, to a tracked carriage of the 203 mm howitzer M1931 (B-4).

Late in 1936, the Bolshevik Plant delivered an experimental series of six pieces. A number of longer (55 calibres) barrels and a number of barrels with deeper rifling were manufactured. The B-30 barrels were also used for ultimately unsuccessful experiments with pre-rifled shells and with "Ansaldo system" variable depth rifling.

While generally similar to the competing design, the Br-2 had different barrel construction (built-up vs loose liner
Liner
Liner or LINER may refer to:In line drawing:* Eye liner, a type of makeup* Liner, a sable brush used by coach paintersIn linings:...

), slightly different breechblock
Breechblock
A breechblock is the part of the firearm action that closes the breech of a weapon at the moment of firing....

 and featured an equilibrating mechanism.

Despite results of trials, which favored the B-30, the Artillery Directorate decided to adopt the Br-2. The reasons for the decision are not clear. However, it was decided to switch to free tube barrel construction in production pieces, making the gun somewhat more similar to the B-30.

Improved variants

Although the Br-2 was adopted, it was evident that the gun had significant drawbacks. One of the problems was very short life of the barrel: it took about 100 shots for the muzzle velocity to drop 4%. In an attempt to tackle the problem, an experimental piece with longer (55 calibers) barrel was produced; another experimental barrel had smaller chamber and deeper rifling. The latter solution was eventually preferred and from 1938 a variant with deep rifling replaced the original barrel in production. It was claimed that the new variant had five times longer service life. However, service life of the new barrel was measured using different criterion (10% drop in muzzle velocity), so actual improvement was probably much smaller.

Another drawback of the gun was its low mobility, aggravated by separate transportation of the barrel. Attempts to improve the tracked carriage (such as the experimental T-117, which was tried out in 1939) were ultimately unsuccessful. In 1938 the Artillery Directorate issued specifications for a wheeled carriage for the Br-2 and the 203 mm howitzer M1931 (B-4). The project was handled by the design bureau of Plant no. 172 (The Perm
Perm
Perm is a city and the administrative center of Perm Krai, Russia, located on the banks of the Kama River, in the European part of Russia near the Ural Mountains. From 1940 to 1957 it was named Molotov ....

 plant), headed by F. F. Petrov
Fyodor Petrov
Fyodor Fyodorovich Petrov was a Soviet artillery designer....

. Because the design bureau was busy with other tasks, the development of the new carriage - factory index M-50 - advanced slowly; it never advanced past the design phase and was canceled after the outbreak of the German-Soviet War. An improved wheeled cart Br-15 for barrel transportation was considered in 1940 but was never adopted, because it couldn't improve the mobility of the carriage. It took until 1955 to develop a variant of the Br-2 - designated Br-2M - which had wheeled carriage and didn't require sepatare transportation.

The Br-2 was also used in a number of unsuccessful experiments with discarding sabot shells
Sabot
A sabot is a device used in a firearm or cannon to fire a projectile, such as a bullet, that is smaller than the bore diameter, or which must be held in a precise position. The term is also applied to a battery stub case, a device used similarly to make a small electrical battery usable in a...

, intended to increase range. These included experiments carried out in 1940, with 162 mm barrel firing 162/100 mm shells. The barrel was damaged during the experiments; additionally, the gun was found to have unsatisfactory ballistics and problems with loading. Firing 152/107 mm shells failed to produce significant improvement in range.

Br-19

The Br-19 was an experimental piece which combined elements of late production Br-2 (breechblock, barrel with deep rifling) with elements of B-30. The gun was tried out in 1939; it found superior to the Br-2 and was recommended for production, which, however, never started.

Br-21

The Br-21 was an experimental 180 mm gun developed privately at the Barrikady Plant by mating Br-2 barrel bored out to the 180 mm caliber to carriage of B-4. The gun reached trials on 20 December 1939. The gun turned out to be more powerful and accurate than the Br-2, but was never adopted, because of the need to produce a new ammunition.

Production

The Br-2 was in production from 1936 or 1937 to 1940. At least 37 pieces were manufactured. Early pieces had barrels with the original "shallow" rifling (at least seven, built in 1936-37), while late production pieces had barrels with the newer "deep" rifling (27 in 1939-40).

Description

The Br-2 had a long - 47.2 calibers - barrel of free-tube construction, with interrupted screw
Interrupted screw
An interrupted screw or interrupted thread is a mechanical device typically used in the breech of artillery guns. It was invented circa 1845....

 breech
Breechblock
A breechblock is the part of the firearm action that closes the breech of a weapon at the moment of firing....

. The recoil
Recoil
Recoil is the backward momentum of a gun when it is discharged. In technical terms, the recoil caused by the gun exactly balances the forward momentum of the projectile and exhaust gasses, according to Newton's third law...

 system with variable recoil length consisted of hydraulic recoil buffer and hydropneumatic recuperator. The gun utilized bag loading ammunition. For assistance in loading, a special hoisting crane was used.

The single trail tracked carriage was essentially the same as used for the 203 mm howitzer M1931 (B-4) and the 280 mm mortar M1939 (Br-5)
280 mm mortar M1939 (Br-5)
The 280 mm mortar M1939 was a Soviet heavy artillery piece used during World War II....

. It included an equilibrating mechanism of pushing type. The carriage allowed transportation of the weapon to short distances wit the speed of 5–8 km/h. For longer distances, the barrel was removed from the carriage and transported separately on a special cart. In this case, it took from 45 minutes to two hours to prepare the weapon for combat.

Several types of carts were used for barrel transportation. Guns produced in 1937 received the Br-6 cart. Other types used were the wheeled Br-10 (11.1 tons with the barrel) and the tracked Br-29 (13.42 tons with the barrel). In the trials report of 7 August 1938 both were referred to as unsatisfactory; the former because of bad passability and the latter because of excessive weight.

For transportation of carriages, Voroshilovets tracked gun tractors were used. Less powerful Komintern tracked gun tractors were employed to pull gun carts.

Organization and service

As of June 1941, the Br-2 guns were eissued to the heavy gun regiment
Regiment
A regiment is a major tactical military unit, composed of variable numbers of batteries, squadrons or battalions, commanded by a colonel or lieutenant colonel...

 of the Reserve of the Main Command. The regiment consisted of four battalion
Battalion
A battalion is a military unit of around 300–1,200 soldiers usually consisting of between two and seven companies and typically commanded by either a Lieutenant Colonel or a Colonel...

s, each with three two-gun batteries
Artillery battery
In military organizations, an artillery battery is a unit of guns, mortars, rockets or missiles so grouped in order to facilitate better battlefield communication and command and control, as well as to provide dispersion for its constituent gunnery crews and their systems...

, totaling 24 pieces. Two independent two-gun batteries also existed. After the outbreak of the German-Soviet War, the gun was employed by independent six-gun battalions. Later the organization was changed once again, to super heavy gun regiments of four two-gun batteries, totaling six Br-2 and two 210 mm gun M1939 (Br-17)
210 mm gun M1939 (Br-17)
The 210 mm gun M1939 was a Czechoslovak heavy siege gun used by the Soviet Union during World War II. After the Germans occupied Czechoslovakia in March 1939 they took over the Škoda Works, which had been working on this design and a companion 305 mm howitzer. As a result of the...

. By May 1945, the RKKA had four such regiments.

The Br-2 (or possibly B-30) saw combat in the Winter War
Winter War
The Winter War was a military conflict between the Soviet Union and Finland. It began with a Soviet offensive on 30 November 1939 – three months after the start of World War II and the Soviet invasion of Poland – and ended on 13 March 1940 with the Moscow Peace Treaty...

 against Finland
Finland
Finland , officially the Republic of Finland, is a Nordic country situated in the Fennoscandian region of Northern Europe. It is bordered by Sweden in the west, Norway in the north and Russia in the east, while Estonia lies to its south across the Gulf of Finland.Around 5.4 million people reside...

, one piece was lost. As of June 1941, the RKKA possessed 37 or 38 pieces, of them 24 in the aforementioned heavy artillery regiment and further four in two independent batteries. These batteries were given to the Arkhangelsk
Arkhangelsk
Arkhangelsk , formerly known as Archangel in English, is a city and the administrative center of Arkhangelsk Oblast, Russia. It lies on both banks of the Northern Dvina River near its exit into the White Sea in the north of European Russia. The city spreads for over along the banks of the river...

 military district for use as coastal artillery
Coastal artillery
Coastal artillery is the branch of armed forces concerned with operating anti-ship artillery or fixed gun batteries in coastal fortifications....

. The rest of the guns, mainly early production guns with shallow rifling and experimental pieces, remained in storage depots and proving grounds. There is only a fragmentary information of the actual combat use of the Br-2. Some sources mention the guns being used in the Battle of Kursk
Battle of Kursk
The Battle of Kursk took place when German and Soviet forces confronted each other on the Eastern Front during World War II in the vicinity of the city of Kursk, in the Soviet Union in July and August 1943. It remains both the largest series of armored clashes, including the Battle of Prokhorovka,...

; the 8th Guards Army employed them in the Battle of the Seelow Heights
Battle of the Seelow Heights
The Battle of the Seelow Heights , was a part of the Seelow-Berlin Offensive Operation ; one of the last assaults on large entrenched defensive positions of World War II. It was fought over three days, from 16–19 April 1945...

. By the end of the war, Reserve of the Main Command still had 28 pieces, so apparently none were lost.

The modernized Br-2M remained in service at least until 1970s.

Surviving pieces can be seen in the Central Armed Forces Museum
Central Armed Forces Museum
The Central Armed Forces Museum also known as the Museum of the Soviet Army, is located in northern Moscow near the Red Army Theater.-History:...

 (Moscow
Moscow
Moscow is the capital, the most populous city, and the most populous federal subject of Russia. The city is a major political, economic, cultural, scientific, religious, financial, educational, and transportation centre of Russia and the continent...

), in the Artillery Museum (Saint Petersburg
Saint Petersburg
Saint Petersburg is a city and a federal subject of Russia located on the Neva River at the head of the Gulf of Finland on the Baltic Sea...

) and on the Sapun Mountain (Sevastopol
Sevastopol
Sevastopol is a city on rights of administrative division of Ukraine, located on the Black Sea coast of the Crimea peninsula. It has a population of 342,451 . Sevastopol is the second largest port in Ukraine, after the Port of Odessa....

).

Variants

  • Br-2 with built-up barrel - experimental piece.
  • Br-2 with shallow rifling - at least seven pieces manufactured in 1936-37.
  • Br-2 with 162 mm barrel - experimental piece.
  • Br-2 with deep rifling - 27 pieces in 1939-40.
  • Br-2M - Br-2 barrel on a new wheeled carriage, adopted in 1955.

Self-propelled mounts

The only self-propelled mount of the Br-2 was a variant of the experimental SU-14
SU-14
The SU-14 was a prototype Soviet heavy self-propelled gun built on a T-35 chassis. The SU-14-1 variant of 1936 carried a 152.4 mm B-10 naval cannon which could fire 43.5 kilogram shells at ranges up to 20 km. Its armour was 20 to 30mm thick. It never entered serial production.-External...

, based on the chassis of the T-35
T-35
The T-35 was a Soviet multi-turreted heavy tank of the interwar period and early Second World War that saw limited production and service with the Red Army. It was the only five-turreted heavy tank in the world to reach production but proved to be slow and mechanically unreliable...

 heavy tank with elements of T-28
T-28
The Soviet T-28 was among the world's first medium tanks. The prototype was completed in 1931 and production began in late 1932. It was an infantry-support tank intended to break through fortified defences...

 medium tank, and intended to carry either 203 mm howitzer or 152 mm gun. The prototype armed with Br-2 is referred to as SU-14Br-2. In Autumn 1941 the experimental piece shelled German forces
Wehrmacht
The Wehrmacht – from , to defend and , the might/power) were the unified armed forces of Nazi Germany from 1935 to 1945. It consisted of the Heer , the Kriegsmarine and the Luftwaffe .-Origin and use of the term:...

 from Kubinka
Kubinka
Kubinka is a town in Odintsovsky District of Moscow Oblast, Russia, located on the Setun River, west of Moscow. Population: Kubinka was the location of the Soviet Union's tank proving grounds, and today is the home of the Kubinka Tank Museum...

 proving ground
Proving ground
A proving ground is the US name for a military installation or reservation where weapons or other military technology are experimented or tested, or where military tactics are tested...

. The vehicle is still on display in the Kubinka Tank Museum
Kubinka Tank Museum
The Kubinka Tank Museum is a large museum of armoured fighting vehicles in Kubinka, just outside Moscow. It has many famous tanks from World War I, World War II and the Cold War. The museum also houses many unique vehicles, such as the Panzer VIII Maus, Troyanov super-heavy tank and a Karl-Gerät...

.

Summary

The Br-2 project can hardly be seen as a success. Its main problem was the tracked carriage, intended to provide better passability. The carriage was too heavy, unsuitable to transportation of the complete weapon and provided very limited traverse of 8 degrees. To manoeuvre the gun beyond the eight-degrees sector took at least 25 minutes. Separate transportation of the barrel meant setup time of at least 45 minutes. Powerful artillery tractors were needed to move the massive gun, especially in poor road conditions. Service life of the barrel and rate of fire were also unsatisfactory. An attempt to remedy the barrel life problem led to existence of two types of barrels, which utilized different ammunition. In addition to the mentioned deficiences, the weapon was in short supply, with only 37 or 38 pieces available during World War II.

For the sake of comparison, Wehrmacht
Wehrmacht
The Wehrmacht – from , to defend and , the might/power) were the unified armed forces of Nazi Germany from 1935 to 1945. It consisted of the Heer , the Kriegsmarine and the Luftwaffe .-Origin and use of the term:...

 possessed several models of heavy 15 cm guns: K 16
15 cm Kanone 16
The 15 cm Kanone 16 was a heavy field gun used by Germany in World War I and World War II. Guns turned over to Belgium as reparations after World War I were taken into Wehrmacht service after the conquest of the Belgium as the 15 cm K 429...

, K 18, K 39; a limited number of naval SK C/28
15 cm SK C/28
The 15 cm SK C/28 was a German medium-caliber naval gun used during the Second World War. It served as the secondary armament for the Bismarck class and Scharnhorst-class battleships, Deutschland-class pocket battleships and the Graf Zeppelin class aircraft carrier...

 guns were fitted with wheeled carriages. The most numerous of those was K 18, with at least 101 pieces built. Like with Br-2, its barrel and carriage were transported separately; it also had similar range of 24,740 m. However, the Rheinmetall
Rheinmetall
Rheinmetall AG is a German automotive and defence company with factories in Düsseldorf, Kassel and Unterlüß. The company has a long tradition of making guns and artillery pieces...

 design was superior in many respects. It was lighter (18,310 kg in travel position, 12,930 kg in combat position), used turntable platform to achieve relatively quick 360 degrees traverse, and had wider range of ammunition (though its high explosive shell contained about one kg less explosives). Another comparable weapon was the 17 cm K 18 MrsLaf (338 pieces). Similar to the Br-2 in weight (travel 23,375 kg, combat 17,520 kg), and also separately transported, this gun was far more powerful, firing 68 kg shells to the range of 29.6 km, and had all-around traverse by means of a turntable platform.

Also of interest is a comparison to the American
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 155 mm M1/M2 gun, nicknamed Long Tom
155 mm Long Tom
The 155 mm Gun M1 and M2 , widely known as Long Tom, were 155 millimeter calibre field guns used by the United States armed forces during World War II and Korean War. The Long Tom replaced the Canon de 155 mm GPF in United States service.-Development:Before entering World War I, the United...

. Somewhat inferior in range (23.2 km), Long Tom was much lighter (13.9 tons in travel position) and was transported as a complete weapon. Its split trail carriage with firing base allowed traverse of 60° and provided better stability in firing position.

Ammunition

The Br-2 fired specially developed ammunition. The shallow rifling pieces and the deep rifling ones also used different projectiles. High explosive / fragmentation and anti-concrete projectiles were produced; there is some indication that chemical and "special" (i.e. nuclear) projectiles also existed, though it is not completely clear. The bag charge allowed three charges - full, no. 1 and no. 2.

Ammunition for the pieces with deep rifling.
Type Model Weight, kg HE weight, kg Muzzle velocity, m/s Range, m
HE-Frag OF-551 48.9 6.53 880 25,000
Anti-concrete G-551 49.0



Ammunition for the pieces with shallow rifling
Type Model Weight, kg HE weight, kg Muzzle velocity, m/s Range, m
HE-Frag OF-550 49.0 7.0 880 27,000
Anti-concrete Г-550 49.0
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