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.
|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||
|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)
|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 1|
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."
- ^Outfits were about 75% HEI and 25% API.
|Designation||Single Mount for C/30 and C/38: Pedestal L/30
Quad Mount for Flak 35: Vierling L/38 1
Quad 3-D stabilized Mount: Vierling C 38/43
U-boat twin mount: LM44U 2
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 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 Rate||All except LM44U: Manually operated, only
LM44U: 30 degrees per second
- ^In the quadruple Flak 35 mounting, distance between gun axes was 67.4 cm (26.5 inches) horizontally, 28 cm (11.0 inches) vertically.
- ^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.
- ^The Army Flakvierling 38 carriage had an elevation range of -10 / +110 degrees.