Germany
5.5 cm/77 (2.17") Gerät 58
Updated 20 May 2012
Gas-operated, air-cooled automatic gun developed for both land and naval use.  Only two prototypes were completed before the end of World War II.  Interesting in that no alloy steels were to be used in its construction, a reflection of the growing shortages in Germany as World War II neared its end.

Used a five-round ammunition clip and the gun fired with the breech locked as it moved forward from recoil.
WNGER_55_Gerat58_pic.jpg

One of the two completed prototypes
Picture copyrighted by M.J. Whitley
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Gun Characteristics
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Designation 5.5 cm/77 (2.165") Gerät 58
Ship Class Used On Planed for the Type 1942C destroyers
Date Of Design 1944
Date In Service N/A (prototypes, only)
Gun Weight 1,430 lbs. (650 kg)
Gun Length oa 236 in. (6.000 m)
Barrel Length 166 in (4.220 m)
Rifling Length 148 in. (3.750 m)
Grooves (20) 0.030 in deep x 0.171 in (0.75 mm x 4.34 mm)
Lands 0.169 in (4.3 mm)
Twist Increasing RH 1 in 90 to 1 in 25.6
Chamber Volume N/A
Rate Of Fire 120 - 150 rounds per minute cyclic
Could also be fired in single-shot mode
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Ammunition
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Type Fixed
Weight of Complete Round 11.8 lbs. (5.3 kg)
Projectile Types and Weights AA - 4.4 lbs. (2.0 kg)
Bursting Charge 0.46 lbs. (1.0 kg)
Projectile Length N/A - Complete Round 26.2 in (665 mm)
Propellant Charge 2.4 lbs. (1.1 kg) (Probably RPC/40N)
Cartridge 55 x 450B
Muzzle Velocity 3,350 fps (1,020 mps)
Working Pressure N/A
Approximate Barrel Life N/A
Ammunition stowage per gun N/A
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Range
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Elevation With 4.4 lbs. (2.0 kg) Shell
Range @ 45 degrees about 4,370 yards (4,000 m) effective
AA Ceiling @ 80 degrees about 6,900 feet (2,500 m) effective
Note:

Time of flight with MV = 3,350 fps (1,020 mps)
   1,090 yards (1,000 m): 1.10 seconds
   2,190 yards (2,000 m):  2.50 seconds
   3,280 yards (3,000 m):  4.34 seconds
   4,370 yards (4,000 m):  6.75 seconds
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Mount / Turret Data
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Designation Single Mounts
Weight  N/A
Elevation about -10 / 90 degrees
Elevation Rate N/A
Train 360 degrees
Train Rate N/A
Gun recoil N/A
Notes:  Various types of mountings were under investigation, including triaxial and quadaxial designs as well as an Army biaxial mounting.
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Data from
"Naval Weapons of World War Two" by John Campbell
"German Warships 1815-1945" by Erich Gröner
"Rapid Fire" by Anthony G. Williams
Page History

05 August 2006 - Benchmark
20 May 2012 - Added Cartridge Data