2 cm/65 Flakvierling 38 (20 mm)

2 cm/65 Flakvierling 38

Information

Automatic CannonType

Germany County of Origin

General Characteristics

20 mmDiameter

1.30 mLength

40 roundsBelt Capacity

480 rpmRate of Fire

835 m/sMuzzle Velocity

46 mmMax Penetration

Production History

Rheinmetall-BorsigDesigner

Full ProductionProduction Status

1940 - 1945Produced

Description

The 2 cm/65 Flakvierling 38 is a German WWII light naval twin anti-aircraft cannon mount found on some motor torpedo boats and barges, and on many destroyers and cruisers in the German naval tech tree, either with or without a gunshield. The Flakzwilling 38 is a quadruple mount of 2 cm/65 C/38 (20 mm). A twin mount variant also exists, called 2 cm/65 Flakzwilling 38 (20 mm).

General info

Each gun of the 2 cm/65 Flakvierling 38 has a barrel diameter of 20 mm, a barrel length of 1.300 m, and weighs 57.5 kg. It has a magazine size of 40 rounds per gun and has a rate of fire of 480 rounds per minute per gun.

Available shells

Depending on the vehicle, there are up to three belts available. Note that Default and Universal refer to the same belt, depending on the vehicle.

• Default/Universal: AP-T/AP/HEF-T/HEF
• 20 mm HET: HEF/HEF-T/HEF/AP
• 25 mm APT: AP/AP-T/AP/HEF

Not all belts listed are available on all vehicles equipped with this weapon.

Penetration Statistics
Ammunition	Penetration @ 0° Angle of Attack (mm)
	10 m	100 m	500 m	1,000 m	1,500 m	2,000 m
AP-T	40	38	31	26	22	19
AP	40	38	31	26	22	19
HEF-T	_	_	_	_	_	_
HEF	_	_	_	_	_	_

Shell Details
Ammunition	Projectile Mass (kg)	Velocity (m/s)	Explosive Type	Explosive Mass (kg)	TNT Equivalent (kg)	Fuse Delay (m)	Fuse Sensitivity (mm)	Normalization at 30°	Ricochet
									0%	50%	100%
AP-T	0.148	785	N/A	N/A	N/A	N/A	N/A	_°	_°	_°	_°
AP	0.148	785	N/A	N/A	N/A	N/A	N/A	_°	_°	_°	_°
HEF-T	0.115	835	NP 10	0.0062	0.01054	0.0	0.1	_°	_°	_°	_°
HEF	0.115	835	NP 10	0.0062	0.01054	0.0	0.1	_°	_°	_°	_°

NP 10 is equivalent to 1.7x TNT.

Comparison with analogues

Compared to other 20 mm guns within the German naval tree:

• MG 151/20 (20 mm): MG 151/20 has a larger belt size (600 rounds) and a much greater rate of fire (700 rpm); but it has a weaker AP shell (25 mmm max penetration) with a slower muzzle velocity (705 m/s), and it can overheat if fired for too long.

• 2 cm/65 C/30 (20 mm): The predecessor of 2 cm/65 C/38, it has a smaller magazine size (20 rounds) and has a lower rate of fire (312 rpm). The same ammunition is used.

• 2 cm/65 C/38 (20 mm): The single mount variant, it has the same rate of fire (480 rpm). The same ammunition is used.

• 2 cm/65 Flakzwilling 38 (20 mm): A twin mount variant, each gun has a greater rate of fire (500 rpm). The same ammunition is used.

Common 20 mm guns in other nations include:

• Oerlikon Mk.II (20 mm): 20 mm Oerlikon Mk.II, and its derivatives, have a larger magazine (60 rounds) and have a greater muzzle velocity (844 m/s); but they have a lower rate of fire (450 rpm), and fire a weaker AP shell (40 mm max penetration) and a weaker HE shell (0.006525 kg TNT equivalence).

• Type 98 (20 mm): 20 mm Type 98 has a greater muzzle velocity (844 m/s); but has a smaller magazine (20 rounds), has a lower rate of fire (300 rpm), and fires a weaker AP shell (40 mm max penetration) and a weaker HE shell (0.006171 kg TNT equivalence).

Usage in battles

The 2 cm/65 Flakvierling 38 has a very large TNT equivalent explosive mass compared to other guns of similar calibre. With its great rate of fire and high-damaging rounds, and the fact that it consists of four guns, Flakvierling 38 can easily destroyer enemy boats in a single burst with plenty of ammunition left to spare. It also works excellently as an anti-aircraft weapon.

However, the Flakvierling 38 is held back by its effective range of approximately 2.00 km using the 20 mm HET belt. This can be slightly increased to approximately 2.30 km using the 20 mm APT belt, although even so, hitting moving targets at such ranges can be difficult. Boats armed with Flakvierling 38 should instead aim to close the distance and overwhelm enemy boats with their firepower.

Also keep in mind that, because of the rate of fire and amount of guns, Flakvierling 38 can run out of ammunition on certain boats. It's always a good idea to practice conserving ammunition, even disabling the AI gunners if necessary. On larger ships though, this isn't much of an issue.

The effective range of the Flakvierling 38 is approximately 2.00 km with the 20 mm HET belt, though if using the 20 mm APT belt, the effect range can be increased to roughly 2.30 km. Even so, hitting moving targets at such ranges can be difficult because of the relatively low muzzle velocity and the small mass of the rounds. Boats armed with Flakvierling 38 should aim to close the distance where they can overwhelm enemy boats with their firepower.

The primary belt choice for this gun should be the 20 mm HET belt since it contains the highest HE:AP ratio. Several 20 APT belts should also be taken to deal with armoured targets, primarily USSR armoured river patrol boats. For destroyers and cruisers armed with Flakzwilling 38, if the option is available, only take 20 mm HET, since the main guns can handle any armoured targets much better.

Pros and cons

Pros:

• Very high explosive mass
• Above average AP penetration
• High rate of fire

Cons:

• Below average muzzle velocity

History

Development began in 1938 for a replacement for the Flak 30, an army version of the 2 cm/65 C/30 after issues arose in its slow rate of fire and small ammunition magazine size. Rheinmetall began production of the new gun, Flak 38, in 1939, with it entering service the same year. In 1940, a naval version, 2 cm/65 C/38, entered production and service in the Kriegsmarine, where it would replace the older 2 cm/65 C/30.

The 2 cm/65 C/38 had the same dimensions as its predecessor, with a bore diameter of 20 mm and a barrel length of 1.300 m, while also managing to be 6.5 kg lighter at 57.7 kg total weight. Like the 2 cm/65 C/30, the gun was fully automatic and recoil-operated, and it fired the same ammunition: a HE round that weighed 0.134 kg and had a muzzle velocity of 835 m/s; and an AP round that weighed 0.148 kg and had a muzzle velocity of 800 m/s. The barrel was also of a monobloc design and could be easily removed and replaced. However, unlike its predecessor, 2 cm/65 C/38 was fed with 40-round magazines, as opposed to the 20-round magazines of the C/30, and had a cyclic rate of fire of 480 rounds per minute and an effective rate of fire of 220 rounds per minute, a noticeable improvement over the 280 rounds per minute cyclic and 120 rounds per minute effective of the C/30.

Available for the gun were three mounts: L/30, L41, LM44U. L/30 was the standard single mount for the 2 cm/65 C/38. It weighed 416 kg with the gun and was manually operated, able to depress -11° and elevate +85°. At its base was a small ammunition storage for up to five magazines, which would be manually loaded by the crew into the left side of the gun. On the right side was a bag which would catch spent casings. L41 was a single mount designed for use in the comparatively confined spaces of S-Boote. It weighed 500 kg, could only depress to -10°, and traversed with the use of a hand crank. LM44U was a special twin mount which weighed 3,600 kg total and was designed to withstand up to 200 m depths for use on submarines. The mount could depress -10° and elevate +78°. It was driven by hydraulic devices and could train at a rate of 30°/s and could elevate at a rate of 30°/s or 60°/s, set by the operator who also fired the guns using two foot pedals, one for each gun.

A highly successful configuration of the 2 cm/65 C/38 was the 2 cm Flakvierling C/38, which consisted of four guns in a quadruple mount, arrange 28 cm apart vertically and 67.4 cm apart horizontally. The Flakvierling C/38 was manually operated with two hand cranks, one for training and one for elevation, by an operator who said directly behind the guns and fired them using two foot pedals. The right-hand side guns were arranged upside-down such that ammunition would be loaded in from the right-hand side. Ammunition was manually loaded into all of the guns from each side by the crew from ammunition racks at the base and spent casings fell down the middle into a receptacle. There were versions produced with and without the gun shield. For the Flakvierling C/38, two mounts were available: L/38 and L38/43. L/38 weighed 2,150 kg with the guns, and it could depress -10° and elevate +90°; L38/43, designed in 1943 and introduced in 1944, was a 3-D stabilized L/38 mount.

The 2 cm/65 C/38 was a highly successful gun and became the standard light anti-aircraft cannon of the Kriegsmarine upon its introduction in 1940, with it being mounted on nearly every ship.

Media

Images

• 

  Flakvierling 38 without gunshield, on Nürnberg

See also

• 2 cm/65 C/30 (20 mm)
• 2 cm/65 C/38 (20 mm)
• 2 cm/65 Flakzwilling 38 (20 mm)
• Oerlikon Mk.II (20 mm)

External links

• Lone Sentry - 2 cm Flakvierling 38: A.A./A.T. Gun - Originally published as Catalog of Enemy Ordnance Material, United States Office of the Chief of Ordnance, 1945, p. 133
• NavWeaps - 2 cm/65 (0.79") C/30 and C/38 AA MG
• Wikipedia - 2 cm Flak 30/38/Flakvierling