2 cm Flakvierling 38

2 cm Flak 30
A 2 cm Flak 30 and its crew in Seine-et-Oise, France, August 1944
Type	Anti-aircraft cannon
Place of origin	Nazi Germany
Service history
In service	April 1934–45
Used by	Nazi Germany Finland
Wars	World War II
Production history
Manufacturer	Rheinmetall-Borsig Mauser
Produced	1934–45
No. built	more than 144,000 (Flakvierling count per barrel)
Variants	2 cm Flak 38, Gebirgsflak 38, Flakvierling 38
Specifications
Weight	450 kg (992 lbs)
Length	4.08 m (13 ft 5 in)
Barrel length	1.3 m (4 ft 3 in) L/65
Width	1.81 m (5 ft 11 in)
Height	1.6 m (5 ft 3 in)
Crew	5
Shell	20×138mmB
Caliber	20 mm (.79 in)
Elevation	-12°to ±90°
Traverse	360°
Rate of fire	280–450 rpm (cyclic) 120–180 rpm (practical)
Muzzle velocity	900 m/s (2,953 ft/s)
Effective firing range	2,200 m (2,406 yds) (anti-aircraft)
Maximum firing range	5,783 m (5,230 yds) (ground range)
Feed system	20 round box magazine

2 cm Flakvierling 38
Members of the Panzer-Grenadier-Division Großdeutschland train with a 2 cm Flakvierling 38 (1943)
Type	Anti-Aircraft Gun
Place of origin	Nazi Germany
Service history
In service	March 1940–1945
Used by	Nazi Germany
Wars	World War II
Production history
Designed	1940
Manufacturer	Mauser
Produced	1940–1945
Specifications
Weight	1,509 kg (3,327 lbs)
Length	4.08 m (13 ft 5 in)
Barrel length	1.3 m (4 ft 3 in) L/65
Width	1.81 m (5 ft 11 in)
Height	1.6 m (5 ft 3 in)
Crew	8
Shell	20×138mmB
Caliber	20 mm (.78 in)
Elevation	- 10° - +100°
Traverse	360°
Rate of fire	1,800 rpm (Cyclic) 800 rpm (Practical)
Muzzle velocity	900 m/s (2,953 ft/s)
Effective firing range	2,200 m (2,406 yds) (anti-aircraft)
Maximum firing range	5,783 m (5,230 yds) (ground range)
Feed system	4x 20 round box magazines

The Flak 30 (Flugabwehrkanone 30) and improved Flak 38 were 20 mm anti-aircraft guns used by various German forces throughout World War II. It was not only the primary German light anti-aircraft gun, but by far the most numerously produced German artillery piece throughout the war. It was produced in a variety of models, notably the Flakvierling 38 which combined four Flak 38 onto a single carriage.

The Germans fielded the unrelated early 2 cm Flak 28 just after World War I, but the Treaty of Versailles outlawed these weapons and they were sold to Switzerland.

The original Flak 30 design was developed from the Solothurn ST-5 as a project for the Kriegsmarine, which produced the 20 mm C/30. The gun fired the "Long Solothurn", a 20 × 138 mm belted cartridge that had been developed for the ST-5 and was one of the most powerful 20 mm rounds in existence.

The C/30, featuring a barrel length of 65 calibres, had a rate of about 120 rounds per minute. Disappointingly, it proved to have feeding problems and would often jam, which was offset to some degree by its undersized 20 round-magazine which tended to make reloading a frequent necessity. Nevertheless, the C/30 became the primary shipborne light AA weapon and equipped a large variety of German ships. The MG C/30L variant was also used experimentally as an aircraft weapon, notably on the Heinkel He 112, where its high power allowed it to penetrate armored cars and the light tanks of the era during the Spanish Civil War.

Rheinmetall then started an adaptation of the C/30 for Army use, producing the 2 cm Flak 30. Generally similar to the C/30, the main areas of development were the mount, which was fairly compact. Set-up could be accomplished by dropping the gun to the ground off its two-wheeled carriage and levelling with hand cranks. The result was a triangular base that allowed fire in all directions.

But the main problem with the design remained unsolved. The rate of fire of 120 RPM (rounds per minute) was not particularly fast for a weapon of this calibre. Rheinmetall responded with the 2 cm Flak 38, which was otherwise similar but increased the rate of fire to 220 RPM and slightly lowered overall weight to 420 kg. The Flak 38 was accepted as the standard Army gun in 1939, and by the Kriegsmarine as the C/38.