Germany
2 cm/65 (0.79") C/30
2 cm/65 (0.79") C/38 AA MG
Updated 12 February 2015
Not to be confused with the Oerlikon 20 mm gun used by the Allies, these German 2 cm weapons were manufactured by Rheinmetall.  The Rheinmetall design was developed from an earlier Solothurn weapon, the ST-5.  Both the C/30 and the C/38 guns were fully automatic.

The C/30 model was prone to jamming and used a small magazine (20 rounds) which meant frequent pauses for reloading.  The later C/38 was a much improved weapon which used a 40 round magazine.  A very successful variation of this weapon was the Flak 35, which combined four C/38 guns in a single quad mounting.  A three-dimensional stabilized naval-mount was introduced in 1944.

The C/38 was also produced in very sophisticated twin mount for U-boats.  These were able to withstand a 550 foot (200 m) diving depth.

WNGER_20mm-65_c30_bag_pic.jpg

2 cm/65 C30 showing 20-round magazine
The sailor at the lower left is holding a rangefinder.  The bag is to catch expended shell casings.
Photograph courtesy of Peter Lienau

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Click here for additional pictures
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Gun Characteristics
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Designation 2 cm/65 (0.79") C/30
2 cm/65 (0.79") C/38
Ship Class Used On Almost all
Date Of Design 1930 / 1938
Date In Service 1934 / 1940
Gun Weight C/30:  141 lbs. (64 kg) 
C/38:  129 lbs. (57.5 kg)
Gun Length oa 88.7 in (2.2525 m)
Bore Length 51.2 in (1.300 m)
Rifling Length 46.7 in (1.159 m)
Number Of Grooves (8) 0.0128 in deep x 0.205 in (0.325 mm x 5.2 mm)
Lands 0.104 in (2.65 mm)
Twist Uniform RH 1 in 36
Chamber Volume 2.93 in3 (0.048 dm3)
Rate Of Fire - C/30 280 rounds per minute cyclic 
120 rounds per minute practical
Rate Of Fire - C/38 480 rounds per minute cyclic 
220 rounds per minute practical
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Ammunition
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Type Fixed
Weight of Complete Round 0.71 lbs. (0.320 kg)
Projectile Types and Weights HEI - 0.300 lbs. (0.134 kg)
API - 0.326 lbs. (0.148 kg)
Bursting Charge N/A
Projectile Length 3.1 in (7.85 cm)
Propellant Charge 0.265 lb. (0.120 kg) RPC/38
Cartridge - 0.41 lbs. (0.186 kg)
Muzzle Velocity HEI:  2,740 fps (835 mps)
API:  2,625 fps (800 mps)
Working Pressure 17.8 tons/in2 (2,800 kg/cm2)
Approximate Barrel Life 20,000 - 22,000 rounds
Ammunition stowage per gun 2,000 rounds
Notes:

1) Outfits were about 75% HEI and 25% API.

2) The sources listed below differ as to the ammunition weights, muzzle velocities, propellants and ranges.  I have chosen to use those given in "German Destroyers of World War Two."

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Range
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Elevation With 0.300 lbs. (0.134 kg) HE Shell
Range @ 45 degrees 5,360 yards (4,900 m)
AA Ceiling @ 85 degrees 12,140 feet (3,700 m)
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Mount / Turret Data
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Designation Single Mount for C/30 and C/38:  Pedestal L/30 
Quad Mount for Flak 35: Vierling L/38
Quad 3-D stabilized Mount:  Vierling C 38/43
U-boat twin mount:  LM44U
S-boat single mount:  L41
Weight  L/30 with C/30 gun:  926 lbs. (420 kg) 
L/30 with C/38 gun:  917 lbs. (416 kg) 
Quad Mount Flak 35:  4,740 lbs. (2,150 kg)
LM44U:  7,937 lbs. (3,600 kg)
L41:  1,100 lbs. (500 kg)
Elevation
(see Note 3)
Single Mount:  -11 / +85 degrees
Vierling:  -10 / +90 degrees
LM44U:  -10 / +78 degrees
L41:  -10 / +85 degrees
Elevation Rate All except LM44U:  Manually operated, only

LM44U:  30 or 60 degrees per second

Train 360 degrees
Train Rate All except LM44U:  Manually operated, only

LM44U:  30 degrees per second

Gun recoil N/A
Notes:

1) The LM44U had hydraulic training and elevation controlled by a joy-stick.  Foot pedals operated the triggers.  The mounting was bi-axial, somewhat surprising given the sophistication of the design.

2) In the quadruple Flak 35 mounting, distance between gun axes was 67.4 cm (26.5 inches) horizontally, 28 cm (11.0 inches) vertically.

3) The Army Flakvierling 38 carriage had an elevation range of -10 / +110 degrees.

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Data from
"Naval Weapons of World War Two" by John Campbell
"German Warships 1815-1945" by Erich Gröner
"German Destroyers of World War Two (2nd Edition)" and "German Coastal Forces of World War Two" both by M.J. Whitley
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Special help from Peter Lienau and Robert Hurst
Page History

05 May 2007 - Benchmark
20 May 2012 - Updated to latest template
12 February 2015 - Added note regarding elevation range of Army quad mounting