Monday 2 September 2019

Even More MKb 42(H) Intel

"GAU Artillery Committee Information Department
Information Summary #16
July 1943
New German light machinegun and ammunition for it

In June of 1943, Red Army units captured a new 7.9 mm machinegun firing intermediate cartridges.

A brief description of the machinegun and ammunition, composed by the Small Arms Department of the GAU Artillery Committee and Artillery Academy Research Group follows.

The machinegun (fig. 3-5) has the designation MKb 42(H). It functions by direction gases from the barrel through an opening.

The locking is performed by tilting of the bolt, which pushes against a special tab, which in turn is connected to the barrel. The joining of the barrel to the guide rod (fig. 6) is performed via tilted protrusions, which either lower or raise the back of the barrel when the breech is locked. The front face of the bolt and its recess are tilted with the position of the bolt. The firing pin consists of a three-faced rod, has no spring, and is not fixed to the breech.

The firing pin extends to hit the primer when the guide rod hits the back of the pin.

The machinegun has a gas regulator. The gas impulse is adjusted by changing the volume of the gas chamber by screwing a conical screw in or out of the casing. Below the casing is an attachment for a bipod or a bayonet.

The machinegun can fire either automatically or in single shots. A selector is installed on the metallic trigger housing.

The system is assembled inside a stamped complex-shaped body. The stamped backplate encloses the rear of the body and is held on by a pin with a spring lock. A flat wooden stock with space for a toolkit is built into the backplate. The corners of the stock are covered by metallic covers held by screws.

The spring is located around the receiver axis and pushes against the guide rod plate on one side and into the stock housing on the other.

The charging handle is located on the left and is connected to the guide rod. To put the gun on safety, one must push the handle from the left to the right so that the opposite end goes through an opening in the body. When the bolt is past the sear by about 35 mm, it is possible to put it in safety in the same way. The mobile parts of the system can be put in safety when the bolt is about 40 mm behind the sear. An opening is made in the body on the left, where the handle can be inserted.

The machinegun has a deflector, rigidly attached by a pin to the receiver. The casing is deflected to the right, out of the slot in the body, which is covered by a flap and can be fixed closed. When the bolt is racked or the bolt leaves its rearmost location, the flap opens automatically.

The machinegun has a bayonet.

Main data:
  • Caliber: 7.9 mm
  • Barrel length: 410 mm
  • Weapon length: 935 mm
  • Movement of the guide rod until locking: about 15 mm
  • Movement of the system until the sear: about 118 mm
  • Height of the machinegun with magazine: 325 mm
  • Height of the machinegun without magazine: 205 mm
  • Height of the magazine: 260 mm
  • Width (with handle): 60 mm
  • Width (without handle): 45 mm
The machinegun is fed from detachable double feed 35-38 round magazines. 

A cartridge (fig. 7) weighs 16.8 g and is somewhere in between a rifle and a pistol cartridge. It consists of a bullet, a casing, a propellant charge, and a primer. The 8.2 g bullet consists of a red brass-covered lacquered jacket (1), the lead jacket (2), and a soft steel core (3). The bullet is 26 mm long.

The casing (4) is rimless, steel, lacquered. The length is 32.8 mm, the volume is 2.21 cm². 

The propellant (5) weighs 1.57 g and consists of grainy pyroxyline gunpowder, pistol type. Grains are 0.42 (+/- 0.02) mm by 0.79 (+/- 0.49-0.59) mm. 

The primer (6) is rifle type. It consists of a metal casing, an explosive material, and a foil cover. The explosive material does not contain fulminate of mercury. The explosive material weighs 0.029 g."

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