2 cm Flak 30/38
2 cm Flak 30 in travel configuration in theImperial War Museum London
Type	Anti-aircraft gun
Place of origin	Nazi Germany
Service history
In service	April 1934–1945
Used by	SeeUsers
Wars	World War II Portuguese Colonial War
Production history
Manufacturer	Rheinmetall-Borsig Mauser Ostmarkwerk
Unit cost	3500Reichsmark
Produced	1934–1945
No. built	more than 144,000[1] (Flakvierling count per barrel) Flak 30: 8,000+ Flak 38: 40,000+
Variants	2 cm Flak 38,Gebirgsflak 38, Flakvierling 38
Specifications
Mass	Flak 30: 450 kg (990 lb) Flak 38: 405 kg (893 lb)
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	Flak 30: 280 rpm (cyclic)/120 rpm (practical) Flak 38: 450 rpm (cyclic)/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

TheFlak 30 (Flugzeugabwehrkanone 30) and improvedFlak 38 were 20 mmanti-aircraft guns used by various German forces throughoutWorld 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.^[1] It was produced in a variety of models, notably theFlakvierling 38 which combined four Flak 38autocannons onto a single carriage.

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

The original Flak 30 design was developed from theSolothurn ST-5 as a project for theKriegsmarine, which produced the2 cm 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 more powerful 20 mm rounds.^[2]

The C/30, featuring a barrel length of 65calibres, had a fire rate of about 120 rounds per minute. 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.

TheMG C/30L variant was also used experimentally as an aircraft weapon, notably on theHeinkel He 112, where its high power allowed it to penetrate armoured cars and the light tanks of the era during theSpanish Civil War.

Rheinmetall then started an adaptation of the C/30 for Army use, producing the2 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 off its two-wheeled trailer, "Sonderanhänger 51" (trailer 51) and levelling the gun using hand cranks. The result was a triangular base that permitted 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^{[N 1]} responded with the2 cm Flak 38, which was otherwise similar but increased the rate of fire by 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 the2 cm C/38.

In order to provide airborne and mountain troops with an AA capability,Mauser was contracted to produce a lighter version of the Flak 38, which they introduced as the2 cm Gebirgsflak 38 (2 cm GebFlak 38). It featured a dramatically simplified mount using a tripod that raised the entire gun off the ground, with the additional benefit of allowing the weapon to be set up on an uneven surface. These changes reduced the overall weight of the gun to 276.0 kg. Production started in 1941 and it entered service in 1942.

2 cm Flakvierling 38
Members of thePanzer-Grenadier-Division Großdeutschland train with a 2,0cm 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
Designer	Mauser
Designed	1940
Manufacturer	Mauser Rheinmetall Ostmarkwerk
Produced	1940–1945
No. built	3,768
Specifications
Mass	1,509 kg (3,327 lbs) with trailer
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	2,0cm (.78 in)
Action	Recoil operation[3]
Breech	Rotating bolt
Carriage	Sd.Ah 52 (Special Trailer 52)
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

Even as the Flak 30 was entering service, the Luftwaffe andHeer (army) branches of theWehrmacht had doubts about its effectiveness, given the ever-increasing speeds of low-altitudefighter-bombers and attack aircraft. The Army in particular felt the proper solution was the introduction of the37 mm calibre weapons they had been developing since the 1920s, which had a rate of fire about the same as the Flak 38 but fired a round with almost eight times the weight. This not only made the rounds deadlier on impact, but their higher energy andballistic coefficient allowed them to travel much longer distances, allowing the gun to engage targets at longer ranges. This meant it could keep enemy aircraft under fire over longer time spans.

The 20 mm weapons had always had weak development perspectives, often being reconfigured or redesigned just enough to allow the weapons to find a use. Indeed, it came as a surprise when Rheinmetall introduced the2 cm Flakvierling 38, which improved the weapon just enough to make it competitive again. The termVierling literally translates to "quadruplet" and refers to the four 20 mm autocannon constituting the design.

TheFlakvierling weapon consisted of quad-mounted 2 cm Flak 38 AA guns with collapsing seats, folding handles, andammunition racks. The mount had a triangular base with a jack at each leg for levelling the gun. The tracker traversed and elevated the mount manually using two handwheels. When raised, the weapon measured 307 cm (10 feet 1 inch) high.

Each of the four guns had a separate magazine that held only 20 rounds. This meant that a maximum combined rate of fire of 1,400 rounds per minute was reduced practically to 800 rounds per minute for combat use – which would still require that an emptied magazine be replaced every six seconds, on each of the four guns. This is theattainable rate of fire; thesustained rate of fire is significantly lower due to heat buildup and barrel erosion. Automatic weapons are typically limited to roughly 100 rounds per minute per barrel to give time for the heat to dissipate, although this can be exceeded for short periods if the firing window is brief.

The gun was fired by two pedals – each of which fired two diametrically opposite barrels – in either semi-automatic or automatic mode. The effective vertical range was 2,200 metres. It was also used just as effectively against ground targets as it was against low-flying aircraft.^[4]

The Flak 30/38, when not mounted into any self-propelled mount, was normally transported on a Sd.Ah. 51 trailer and could be towed behind a variety of vehicles, including:

• Cars, such as theKübelwagen andHorch 108;
• Trucks, such as theOpel Blitz,Krupp L 2 H 143,Mercedes-Benz L3000,Borgward B 3000;
• Half-tracks, such as the armouredSd.Kfz. 251, the unarmoredSd.Kfz. 2 andSd.Kfz. 10 light half-track vehicles.

Beside being towed, the Flak 30/38 could be mounted on a variety of vehicles, ranging from being mounted on the rear platform of cars, trucks and half-tracks, including vehicles such as theSd.Kfz. 10/4 and 10/5 (Flak 30 / Flak 38),Sd.Kfz. 11/1 (Flak 38)^[5] to being used for dedicated anti-air vehicles such asFlakpanzer I andFlakpanzer 38(t).

TheFlakvierling four-autocannon anti-aircraft ordnance system, when not mounted into any self-propelled mount, was normally transported Sd. Ah. 52 trailer, and could be towed behind a variety ofhalf-tracks or trucks, such as theOpel Blitz truck, theSd.Kfz. 251 armoured half-track, theSd.Kfz. 10 light half-track, theSd.Kfz. 7 andSd.Kfz. 11 artillery-towing half-track vehicles.

Its versatility concerning the vehicles it could be mounted to a variety of trucks and half-tracks, such as theSd.Kfz. 7/1, included its use even on tank hulls to produce fully armoured mobile anti-aircraft vehicles, such as thePanzer IV-based low-productionFlakpanzer IV "Wirbelwind" and originalFlakpanzer IV "Möbelwagen"-based prototype anti-aircraft tanks.

Several field modifications existed in the war, including mounting the Flakvierling onto 3Panzer IVs, made by SS-HauptsturmführerKarl Wilhelm Krause with the12th SS Panzer DivisionHitlerjugend (which inspired theWirbelwind),^[6] as well as mounting it on a capturedT-34 and aBergepanther (made bySchwere Panzerjäger-Abteilung 653).^[7][8]

In Kriegsmarine use, it was fitted toE-boats,U-boats,Siebel ferries and ships to provide short-range anti-aircraft defence, and was also employed in fixed installations around ports, harbours and other strategic naval targets.

A number of mountings were developed by the Kriegsmarine, including:

• Sockel C/30 - Single mount for C/30 and C/38 gun
• Flakzwilling C/38 - Twin mount for C/38 guns
• Flak C/35 - Quad mount with C/30 guns
• Flak C/38 auf Vierlingslafette C/38 - Quad mount with C/38 guns
• Flakvierling C/38 - Army quad mount adapted for naval use
• C/30/37 - twin mount for mounting on a U-boat
• LM44U - twin mount for mounting on a U-boat
• L41 - single mount for mounting on a E-boat

The Flakvierling was also a common fixture on trains, even onHitler's own command train, where pairs of them were mounted on either end of a "camelback" flatbed car and then covered to make it look like a boxcar, sometimes with a pair of such twin-Flakvierling mount cars for defence, one near each end of Hitler'sFührersonderzug train.

A range of 20x138B ammunition was manufactured for 2 cm Flak weapons, the more commonly used types are listed on the following table.^[9] Other types included practice rounds (markedÜbung orÜb. in German notation) and a number of different AP types including a high-velocityPzGr 40 round with atungsten carbide core in an aluminium body.

• Denmark: 69 in service from 1945 to 1955 in The Royal Danish Navy, where it was known as20 mm Mk M/39 LvSa, mounted on minesweepers of the SØLØVE class and motor torpedo boats of the GLENTEN class.
• Finland: 50 Flak 30 (named20 Itk/30 BSW) delivered from Germany in 1939. 113 Flak 38 (named20 ItK/38 BSW) guns bought during theContinuation War.
•  Germany
• Greece: 108 total in service.
• Lithuania: 150 Flak 30 (named20 mm lėktuvinis automatinis pabūklas, LAP) bought in 1939.
• Netherlands: 30 Flak 30 guns were bought and sent over for the Dutch East Indies army in 1938.
• Portugal: unknown number of Flak 30/38 guns (namedMetralhadora Pesada AA 20mm m/943) bought in 1943 and used by thePortuguese Army during thePortuguese Colonial War (1961–1975).
• Romania: 300 ordered in September 1940, the delivery beginning in May 1941, known asGustloff guns (after one of their manufacturers).^[10]
• Sweden: 56 Flak 30 bought in 1939, designated20 mm lvakan m/39 in Swedish service.

• List of anti-aircraft guns
• List of artillery of Germany
• MG 151 cannon - German 20mm aircraft cannon developed during World War II.
• MG FF cannon - German 20mm aircraft cannon during early World War II. Developed from the SwissOerlikon FF.
• 2 cm KwK 30 - variant for armored cars and light tanks, slightly shortened barrel
• 20 mm Polsten - Equivalent British 20mm anti-aircraft gun, developed from a Polish design which was, in turn, derived from a version of the SwissOerlikon. The blueprints were brought to Britain by its creators after theinvasion of Poland.
• Breda Model 35 - Equivalent Italian 20mm anti-aircraft gun.
• Hispano-Suiza HS.404 - Equivalent French-designed 20mm anti-aircraft gun used by many countries during World War II (also used to arm various aircraft).
• Type 98 20 mm AA machine cannon - Japanese 20mm anti-aircraft gun during World War II.
• Type 2 20 mm AA machine cannon - Japanese 20mm anti-aircraft gun derived from the German Flak 38 during World War II, supplementing the earlier Type 98.
• Automatkanon m/40 - Equivalent Swedish 20mm anti-aircraft gun.

• M45 Quadmount, the closest Allied equivalent to theFlakvierling system

• Gander, Terry and Chamberlain, Peter.Weapons of the Third Reich: An Encyclopedic Survey of All Small Arms, Artillery and Special Weapons of the German Land Forces 1939-1945. New York: Doubleday, 1979ISBN 0-385-15090-3
• Hogg, Ian V.German Artillery of World War Two. 2nd corrected edition. Mechanicsville, PA: Stackpole Books, 1997ISBN 1-85367-480-X

Wikimedia Commons has media related to2 cm FlaK 30/38/Flakvierling.

• Images and models of the 2 cm Flak atPinterest
• Image of the 2 cm Flak 38 Anti Aircraft Gun in Desert camouflage at the Australian war memorial page

• 20 mm artillery
• Autocannon
• Naval anti-aircraft guns
• Anti-aircraft guns of Germany
• Artillery of Switzerland
• World War II anti-aircraft guns
• World War II artillery of Germany
• World War II military equipment of Greece
• Rheinmetall
• Military equipment introduced in the 1930s

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