3 cm MK 303 (Br)
3cm MK 303 Flakzwilling, two 3 cm MK 303 in the twin mount
Type	Anti-aircraft cannon
Place of origin	Nazi Germany
Service history
In service	unknown
Used by	Nazi Germany
Wars	World War II
Production history
Manufacturer	Krieghoff[1]
Produced	1944–1945
No. built	222 (32 in 1944 and 190 in 1945)[1]
Variants	3 cm Flakzwilling MK 303 (Br)
Specifications
Mass	185 kg (408 lbs)[2]
Length	3.145 m (10 ft 3.8 in)
Barrel length	2.2 m (7 ft 3 in) L/73
Shell	30×210mm
Caliber	30 mm (1.18 in)
Elevation	-10°to ±85°
Traverse	360°
Rate of fire	400 rpm (cyclic)
Muzzle velocity	1100 m/s (3,609 ft/s) M-Schos 900 m/s (2,953 ft/s) HE 950 m/s (3,117 ft/s) AP/HE[2]
Feed system	15 cartridge clip

The 3 cm MK 303 Flak and twin-mounted 3 cm MK 303 Flakzwilling (M44) were experimental 30 mm anti-aircraft guns developed in Nazi Germany. They fired the powerful 30x210mm round and only 222 were produced.^[1] The gun was to be installed on Type XXI submarines as AA defense^[3] and its use as AA defense replacing 2 cm Flak and 3.7 cm Flak weapons was also considered. The use of 3 cm M.K. 303 Flakzwilling on Flakpanzer IV "Kugelblitz" was considered, but rejected. The development began in late 1941^[1] and production started in late 1944.

Post War Usage

Postwar PLDvK vz. 53
of Czechoslovak army

In the 50s, the MK 303 was produced in Czechoslovakia under the designation M53, with the clip feed replaced by a 10-round box magazine.^[1] It was also used as armament of SPAAG M53/59 Praga.

References