57 55 J
57 55 J | ||
---|---|---|
Breech Vertical sliding-block | | |
Carriage | Fixed cone mount | |
Elevation | −10° to +32° | |
Muzzle velocity | Actual: 660 m/s (2,200 ft/s) Planned: 900 m/s (3,000 ft/s) | |
Maximum firing range | Actual: 9 km (5.6 mi) Planned: 12.8 km (8 mi) | |
Feed system | Semi-automatic |
The 57 55 J or 57 mm, 55 caliber length model Jokinen coastal gun is a Finnish light
Background
The gun was developed to replace the older 57 mm Nordenfelt and Hotchkiss guns which, while still usable, were getting old and only had
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
Service use
The 57 55 J was accepted for use as a training weapon in the 1950s because of a lack of suitable training guns and no funds to buy new ones. The old 57 mm Nordenfelt and Hotchkiss guns were worn-out, and 76 mm guns were kept in reserve, so the 57 55 J units, among other old guns, were used as training pieces. Some of the guns were converted for sub-caliber training
Notes
^A Sub-caliber training in this context refers to attaching a smaller weapon into a bigger one to reduce wear on the actual weapon. In the case of the 57 55 J, the gun, stripped of mounting and most other equipment, was attached into a barrel of a heavy gun. The 57 55 J was located outside the actual gun and fired normal ammunition; thus this does not refer to modern sabot ammunition or inner tube mounts.
References
- ^ ISBN 951-25-1033-2.
External links
Media related to 57/55 Jokinen at Wikimedia Commons