130 mm/50 B13 Pattern 1936

In 1929 design work began in the Soviet Union for a new 130 mm 45 caliber submarine deck gun that would have the same external ballistics as the older 130 mm/55 B7 Pattern 1913 gun. It was intended for the gun to use a wedge lock and fixed ammunition, but the plans were changed already before the prototype was ordered. Blueprints and a prototype was ordered from Bolshevik Plant no. 232 in 1930. The design bureau director was N. N. Magdasijev and project leader G. N. Rafalovits. Others involved in the design were S. A. Morozov, S. A. Zalazaev, B. A. Lever, V. M. Rosenberg and V. I. Kudrjashov. The gun design was changed from submarine to destroyer weapon using separate instead of fixed ammunition and in 1932 new specifications included a change from 45 to 50 calibers and a screw breech block instead of wedge block. During test firing in 1934—35 several shortcomings were found in the gun design, particularly with the breech and loading mechanism. Because the Leningrad-class destroyers that were supposed to use the guns were already under construction the 130 mm B-13 gun was accepted for mass production in 1935 and the first twelve guns were finished during the same year. ==Models==

In order to match the performance of the longer barreled 130 mm/55 Pattern 1913 gun it was necessary to use a higher barrel pressure in the 130 mm/50 B13 Pattern 1936. This led to such a rapid barrel wear that the Leningrad and Gnevny class destroyers using the first gun versions could not even empty their magazines a single time before needing to change out the barrel. The solution to the excessive barrel wear was found to be deeper rifling grooves. The original design had deep grooves and a barrel life of 130 rounds; a modified version with deep grooves had a barrel life of 1100 rounds. Additionally there existed a model with deep grooves. The gun had 40 grooves with a constant twist. All three gun models with different groove depths had different, mutually incompatible, ammunition, sights and range tables. A loading platform that could be rotated next to the gun barrel was used to deliver the shell to a pneumatic loading mechanism. The gun could be loaded on any elevation angle, but the rate of fire was reduced on elevations higher than +25°. A modified dual-purpose model with 55 caliber barrel suitable for anti-aircraft fire was planned but the project was stopped due to the war. Mountings Early destroyers and coastal guns used single open mountings protected by a Gun shield. An enclosed twin turret was developed for later destroyer classes and monitors. B-13 was the earliest mounting. This was a single mounting open from the rear and protected by a gun shield against shrapnel and bullets. This mounting was used in the destroyers constructed the before Second World War and in coastal and railway guns. The weight of the mount was and it was equipped with indicators for a central fire control system, but had hand-operated training and elevation. To fire the gun, a string would be attached to a hole at the end of the gun, as was the standard system at the time. B-2LM was a twin turret used in later destroyer classes. It was intended to use this turret to arm the , but the ship was equipped with B-13 mounts instead. The destroyer leader was initially equipped with B-13 mounts, but received the planned B-2LM turrets during a refit. Additionally the lead ship of the s, , was also refitted with a single B-2LM turret forward. The turret was used to arm the post-war and s. The weight of the turret was . B-2LMT twin turret was used as the armament on the monitors Sivash and Perekop and with Shilka-class monitors. Weight . B-28 twin turret was used on the monitor Khasan, weight . B-2-U was a planned dual-purpose universal twin turret (U = Universal'naya) that could have been used effectively also as an anti-aircraft weapon. This turret was planned to use a new 55-caliber model of the B-13 gun and to have a maximum elevation of 85° with a weight of . Due to the war the project was stopped and neither the turret nor the guns were produced. ==Service in Soviet Union==

130 mm/50 B13 gun was the standard armament of the newest destroyers of Soviet Union during World War II and it was used to arm the destroyers built in Soviet Union until 1954. The destroyers classes armed with 130 mm/50 B-13 gun were the Leningrad-class (project 1 and modified project 38 Minsk class), Tashkent, Gnevny class, Soobrazitelny class, Opytny, Ognevoy class and Skoryy class. The mass production of the gun resulted in more than one thousand guns being built, and the gun was also used to arm smaller warships and as a coastal gun. The coastal guns remained in use until the fall of the Soviet Union, and in the 1970s 90 guns in 20 batteries were installed in Muravyov-Amursky Peninsula to protect Vladivostok from a possible Chinese attack. ==Service in Finland==

Finland captured several 130 mm/50 B13 guns during the Battle of Hanko. The captured guns were known in Finland as 130/50 N or 130 mm 50 kaliiperin merikanuuna mallia N (130 mm 50 caliber coastal gun model N). Soviet Union had four batteries of B-13 guns in Hanko, but they were damaged or blown up when the Russians evacuated Hanko. Valtion Tykkitehdas (State Artillery Factory) and Helsinki Naval Base ordance personnel succeeded in repairing five guns. Only a few hundred rounds of ammunition were captured, so Finns began manufacturing suitable ammunition domestically. Captured Russian ammunition included modern high explosive fragmentation shells with point and base fuzes and semi-armour piercing shells, while the Finnish produced ammunition were older style high explosive shells. Three captured guns were used for short periods of time in Pihlajasaari and Miessaari forts by Uusimaa Coastal Brigade. Two guns were used to arm the auxiliary gunboats Aunus and Viena. The origin of the designation N (also Nl or NI) is uncertain, but most likely stood for Neuvostoliittolainen (from Soviet Union). The gun had a nickname Nikolajev in Finland. turret of the Polish destroyer ==Service in other countries==

Two Skoryy class destroyers were transferred to the Polish Navy in the late 1950s. Skoryy-class destroyers were also sold to Egypt (six ships) and Indonesia (seven ships). Four Gnevny-class destroyers were donated by Soviet Union to People's Republic of China as Anshan-class destroyers. ==Modifications==

In the early 1940s an attempt was made in the Soviet Union to mount the 130 mm B-13 gun on a tank chassis. After Winter War one of the T-100 tank prototypes was refitted with a hull mounted 130 mm B-13 naval gun. This vehicle was known as SU-100Y and the prototype was used in action during the Battle of Moscow. The prototype survived the war and is now on display in Kubinka Tank Museum. ==References==