MP40 Sub Machine Gun

The MP40 or Maschinenpistole 40 was a 9mm German sub machine gun designed in 1938 by Heinrich Vollmer.

It was commonly referred to as the 'Schmeisser' by Allied troops. This was due to it's similarity to the older MP18 designed by Hugo Schmeisser. Although it shares many design attributes, Schmeisser was not involved with the MP40 design.

Many British airborne officers, including John Waddy preferred to use MP40 over their issued Sten or Thompson machine carbine. 

These guns were originally designed for use with German paratroopers and mechanised infantry, who needed a compact weapon. In fact it has a unique design feature which reflects back to its original intended users. Under the barrel it has a resting bar, with a hooked end. This safety feature was made of either steel or Bakelite. It enabled the user to  rest the barrel, when firing, on the edge of a vehicle door or it's armour plates. The hook stopped the weapon recoiling back in to the vehicle when it was fired. 

The MP40 is very similar to the MP38. The differences in design are not due to mechanical issues, but rather industrial ones. The MP38 is a 'milled gun', with a receiver made from machined/milled  parts, both in steel and aluminium. The MP40 is significantly simplified, by using stamped/pressed parts, to make if far cheaper and easier to produce, but maintaining the same original design attributes. This gave the MP40 it's distinctive ribbed magazine well compared to the smooth machined well (with hole) of the MP38. The aluminium in the grip frame was replaced with steel. As the aluminium was desperately needed for aircraft production.

The MP40 also had an improved (for safety) cocking handle. However this did not come into use until 1942. Although all MP40 were ordered to be retro fitted with this design improvement, few actually were recalled. Both the MP40 & 38 had a 'telescope' design recoil spring inside. This was much easier to clean than the crude, larger springs in other blow back, open bolt weapons of the time. The weapon can also be field stripped very easily, without the need for tools.

The MP40 was widely well regarded by it's users and the Germans quickly adopted it right across its military forces.

However it did suffer from a design flaw that often appeared in many sub machine designs of the era, it's double stacked, single feed magazine. Although a simple and cheap design of magazine it could easily lead to jams or misfire. The magazine also made it difficult to fire from the prone position. In addition the folding stock often would cause the weapon to 'wobble' when fired, and could be awkward to use in heavy combat situations. It can only be used in 'full auto', there is no single shot selector.

Post War many MP40 were captured and then redistributed to irregular armies and militias in the Developing World. It was also adopted by some nations with the Norwegian army only withdrawing both its the MP38 in 1975, but used the MP40 for several more years until it was replaced by the Heckler and Koch MP5.

Today the MP40 can still be seen being used in the Libyan and Syrian civil wars.

Specifications:

Manufactured by Steyr-Mannlicher, Erma Werke, Haenl

Cost:  (1940) 57 RM

Produced between: 1940-45

Estimated: 1,100,000 produced

Weight: 4kg

Length with stock folded: 63cm

Action: Straight blowback, open bolt

Fire rate: 500-550 rounds per minute

Muzzle Velocity: 400 m/s

Effective Range: 100-200m

Feed: 32 round detachable magazine

Ammunition: 9mm Parabellum cartridge