57 55 J
Encyclopedia
57 55 J or 57 mm, 55 caliber length model Jokinen coastal gun was a Finnish
light coastal gun
designed during Continuation War
. This was the first coastal gun designed and manufactured completely in Finland and it was intended to replace the older 57 mm Nordenfelt
and Hotchkiss
guns, but the design was found faulty and only 11 pieces were constructed. They were used for training after World War II until retired in the mid–1960s.
s for aiming. The desire of the Finnish Navy
headquarters operational section to begin domestic manufacturing of coastal and naval guns also influenced the decision to develop 57 55 J. The prototype, partially based on the older Nordenfelt and Hotchkiss guns, was designed by Engineering Lieutenant Colonel Antero Albert Jokinen and was finished in 1941 in the Helsinki naval base. A series of 50 guns was ordered from Valtion Tykkitehdas (VTT, State Artillery Factory) in Jyväskylä
at the turn of 1941 and 1942, but only 10 guns were built in 1944-1945. With the prototype included the final number was 11 complete pieces.
resulting in muzzle velocity of 900 m/s. But when the same gunpowder batch was tested two years later, it produced a barrel pressure of 3500 atm, resulting in unacceptable barrel wear. At first Jokinen intended to settle for a muzzle velocity of 800 m/s, but in the end the muzzle velocity was reduced to 660-670 m/s, no better than the older 57 mm guns. Antero Jokinen has later been criticized for attempting to build a "too good" gun, without considering the abilities of the Finnish industry at the time.
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...
light 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....
designed during Continuation War
Continuation War
The Continuation War was the second of two wars fought between Finland and the Soviet Union during World War II.At the time of the war, the Finnish side used the name to make clear its perceived relationship to the preceding Winter War...
. This was the first coastal gun designed and manufactured completely in Finland and it was intended to replace the older 57 mm Nordenfelt
QF 6 pounder Nordenfelt
The QF 6 pounder Nordenfelt was a light 57 mm naval gun and coast defence gun of the late 19th century used by many countries.Note that this gun should not be confused with the short-barreled 57 mm Cockerill-Nordenfelt "Canon de caponnière" or fortification gun, which was used to arm the...
and Hotchkiss
QF 6 pounder Hotchkiss
The QF 6 pounder Hotchkiss was a light 57 mm naval gun and coast defence gun of the late 19th century used by many countries, and was adapted for use in the early British tanks in World War I.- Canada History :...
guns, but the design was found faulty and only 11 pieces were constructed. They were used for training after World War II until retired in the mid–1960s.
Background
57 55 J was developed to replace the older 57 mm Nordenfelt and Hotchkiss guns which, while still usable, were getting old and only had iron sightIron sight
Iron sights are a system of shaped alignment markers used as a sighting device to assist in the aiming of a device such as a firearm, crossbow, or telescope, and exclude the use of optics as in telescopic sights or reflector sights...
s for aiming. The desire of the Finnish Navy
Finnish Navy
The Finnish Navy is one of the branches of the Finnish Defence Forces. The Navy employs 2,300 people and about 4,300 conscripts are trained each year. Finnish Navy vessels are given the ship prefix "FNS" simply short for "Finnish Navy Ship"...
headquarters operational section to begin domestic manufacturing of coastal and naval guns also influenced the decision to develop 57 55 J. The prototype, partially based on the older Nordenfelt and Hotchkiss guns, was designed by Engineering Lieutenant Colonel Antero Albert Jokinen and was finished in 1941 in the Helsinki naval base. A series of 50 guns was ordered from Valtion Tykkitehdas (VTT, State Artillery Factory) in Jyväskylä
Jyväskylä
Jyväskylä is the capital of Central Finland and the largest city on the Finnish Lakeland, north-east of Tampere and north of Helsinki, on northern coast of lake Päijänne. The city has been continuously one of the most rapidly growing cities in Finland since World War II. The city is surrounded...
at the turn of 1941 and 1942, but only 10 guns were built in 1944-1945. With the prototype included the final number was 11 complete pieces.
Design flaws
When the guns were test-fired in Jyväskylä, it was found that the slide of the semi-automatic mechanism was not strong enough and could bend. The second serious flaw was ammunition. The gunpowder ordered from Valtion Ruutitehdas (State Gunpowder Factory) was designed to produce a barrel pressure of 2800 atmATM
-In science and technology:*Adobe Type Manager, typeface management software from Adobe Systems Allocated*Air traffic management, synonym for air traffic control*Alternating Turing machine, model of computation used in theoretical computer science...
resulting in muzzle velocity of 900 m/s. But when the same gunpowder batch was tested two years later, it produced a barrel pressure of 3500 atm, resulting in unacceptable barrel wear. At first Jokinen intended to settle for a muzzle velocity of 800 m/s, but in the end the muzzle velocity was reduced to 660-670 m/s, no better than the older 57 mm guns. Antero Jokinen has later been criticized for attempting to build a "too good" gun, without considering the abilities of the Finnish industry at the time.