| 3 cm MK 303 (Br) | |
| Origin: | Nazi Germany |
| Type: | Anti-aircraft cannon |
| Is Ranged: | yes |
| Is Artillery: | yes |
| Service: | unknown |
| Used By: | Nazi Germany |
| Wars: | World War II |
| Manufacturer: | Krieghoff[1] |
| Production Date: | 1944–1945 |
| Number: | 222 (32 in 1944 and 190 in 1945) |
| Variants: | 3 cm Flakzwilling MK 303 (Br) |
| Weight: | 185 kg (408 lbs)[2] |
| Length: | 3.145m (10.318feet) |
| Part Length: | 2.2m (07.2feet) L/73 |
| Cartridge: | 30×210mm |
| Caliber: | 30 mm (1.18 in) |
| Rate: | 400 rpm (cyclic) |
| 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 |
| Feed: | 15 cartridge clip |
| Elevation: | -10°to ±85° |
| Traverse: | 360° |
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.
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.