The
Rheinmetall-Borsig
Rheinmetall AG is a German automotive and arms manufacturer, headquartered in Düsseldorf, Germany
Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in ...
MK 103 ("MK" - ''
Maschinenkanone'') was a German
30 mm caliber
30 mm caliber is a specific size of popular autocannon ammunition. Such ammunition includes NATO standard 30×113mmB and 30×173mm (STANAG 4624), Soviet 30×155mmB, 30×165mm, and 30×210mmB, Yugoslav 30×192mm, Anglo-Swiss 30×170mm, and ...
autocannon that was mounted in German combat aircraft during
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...
. Intended to be a dual purpose weapon for anti-tank and air-to-air fighting, it was developed from the
MK 101
MK or mk may refer to:
In arts, entertainment and media Fictional characters
* Moon Knight, a Marvel Comics superhero
* M.K., an ''Into the Badlands (TV series), ''Into the Badlands'' (TV series) character
* Mary Katherine "M.K." Bomba, the prot ...
. Compared to the MK 101 it was faster firing, and was originally intended to develop a higher muzzle velocity than the MK 101. Unlike the MK 101, the MK 103 used a belt feed, allowing it to potentially carry a larger ammunition load. The MK 103 used electrically primed rather than percussion-primed ammunition. The operating mechanism differed from the recoil-operated MK 101 in that it used a combination of gas and
recoil operation
Recoil operation is an operating mechanism used to implement locked breech, autoloading firearms. Recoil operated firearms use the energy of recoil to cycle the action, as opposed to gas operation or blowback operation using the pressure of the p ...
. After firing, gas pressure served to unlock the breech, while barrel recoil was used to cycle the action (eject spent cartridge and load a fresh one).
Because of a combination of lower grade steels and lighter components, the mechanism of the MK 103 was not as strong as the MK 101. To counteract this weakness, HE ammunition with a reduced load of propellant was used, resulting in a loss of about 100 m/s in muzzle velocity compared to the MK 101, but the rate of fire was increased. The MK 103 entered service in 1943 as the main armament of the
Hs 129 B-1 ground-attack/tank-destroyer aircraft, mounted on the underside of the fuselage in a conformal
gun pod
A gun pod is a detachable pod or pack containing machine guns, autocannons, revolver cannons, or rotary cannons and ancillaries, mounted externally on a vehicle such as a military aircraft which may or may not also have its own guns.
Descriptio ...
.
The original specification for the MK 103 called for it to fit inside an aircraft's engine mounting (possibly as a ''Motorkanone'', firing through a hollow propeller hub), but it proved to be too large and heavy to fit into small fighters like the
Bf 109. If mounted elsewhere, such as in the wing, the asymmetric force of the cannon's recoil tended to yaw the aircraft's nose to one side. The only known usage of the MK 103 in a ''Motorkanone'' installation was in the
Do 335. A modified version with a reduced-profile barrel, the MK 103M, was developed and possibly tested for use as a ''Motorkanone'' cannon on single-engine fighter planes such as the Bf 109K, but probably never saw active service. As a consequence, the MK 103 was largely restricted to the role of an air-to-ground weapon for use against armoured vehicles.
Projectile weights for the MK 103 were ) for the
HE/M ammunition and ) for
APCR ammunition. Armour penetration for APCR / 60° / or / 90° / .
Later in the war the MK 103 was also used as a ground-based anti-aircraft (AA) weapon, using single or dual mounts. It was also used as a ''flak'' autocannon in the
Flakpanzer IV "Kugelblitz".
Developed alongside the MK 103 was the lighter
MK 108 cannon
The MK 108 (German: ''Maschinenkanone''—"machine cannon") was a 30 mm caliber autocannon manufactured in Germany during World War II by Rheinmetall‑Borsig for use in aircraft.
The cannon saw widespread use as an anti-bomber weapon during the ...
, which had a shorter barrel and used a modified blow-back operating system. It fired the same projectile, using a smaller cartridge case with less propellant, at a relatively low muzzle velocity. The shorter barrel made it more adaptable, so it saw much greater use.
References
*
Archived DeutscheLuftwaffe.de's MK 103 detailed information page with photos of internal and
gun pod
A gun pod is a detachable pod or pack containing machine guns, autocannons, revolver cannons, or rotary cannons and ancillaries, mounted externally on a vehicle such as a military aircraft which may or may not also have its own guns.
Descriptio ...
mounts-in German
{{WWIIGermanAerialWeapons
30 mm artillery
Autocannon
Aircraft guns
Rheinmetall
Weapons and ammunition introduced in 1943
World War II aerial warfare