MP 40


The MP 40 is a submachine gun chambered for the 9×19mm Parabellum cartridge. Developed in Nazi Germany, it saw service with the Axis forces during World War II and extensive use post-war globally with various fighting forces.
Designed in 1938 by Heinrich Vollmer with inspiration from its predecessor the MP 38, it was heavily used by infantrymen, and by paratroopers, on the Eastern and Western Fronts as well as by the crews of armoured fighting vehicles. Its advanced and modern features made it a favorite among soldiers and popular in countries from various parts of the world after the war.
The Allies often referred to the MP 40 as the "Schmeisser", after the firearms-designer Hugo Schmeisser. In 1917 Schmeisser had designed the MP 18, which was the first mass-produced submachine gun. He did not, however, have anything to do with the design or development of the MP 40, although he held a patent on the magazine.
The MP 40's variants included the MP 40/I and the MP 41. Erma Werke produced an estimated 1.1 million MP 40s between 1940 and 1945.

Development

The Maschinenpistole 40 descended from its predecessor the MP 38, which was in turn based on the MP 36, a prototype made of machined steel. The MP 36 was developed independently by Erma Werke's Berthold Geipel with funding from the German Army. It took design elements from Heinrich Vollmer's VPM 1930 and EMP. Vollmer then worked on Berthold Geipel's MP 36 and in 1938 submitted a prototype to answer a request from the Heereswaffenamt for a new submachine gun, which was adopted as MP 38. The MP 38 incorporated the simpler bolt design of Hugo Schmeisser's M.K.36,III as well as Schmeisser's magazine, but otherwise more closely followed Geipel's MP 36 design. The MP 38 was a simplification of the MP 36, and the MP 40 was a further simplification of the MP 38, with certain cost-saving alterations, most notably in the more extensive use of stamped steel rather than machined parts.

Design

The MP 40 submachine guns are open-bolt, blowback-operated automatic arms. The only mode of fire is automatic, but the relatively low rate of fire permits single shots with controlled trigger pulls. The bolt features a telescoping return spring guide which serves as a pneumatic recoil buffer. The cocking handle was permanently attached to the bolt on early MP 38s, but on late-production MP 38s and MP 40s, the bolt handle was made as a separate part. It also serves as a safety by pushing the head of the handle into one of two separate notches above the main opening; this action locks the bolt in either the cocked or uncocked position. The absence of this feature on early MP 38s resulted in field expedients such as leather harnesses with a small loop that were used to hold the bolt in the forward position.
The MP 38 receiver was made of machined steel, but this was a time-consuming and expensive process. To save time and materials, and thus increase production, construction of the MP 40 receiver was simplified by using stamped steel and electro-spot welding as much as possible. The MP 38 also features longitudinal grooving on the receiver and bolt, as well as a circular opening on the magazine housing. These features were eliminated on the MP 40.
One feature found on most MP 38 and MP 40 submachine guns is an aluminum, steel, or Margolit resting bar under the barrel. This was used to steady the weapon when firing over the side of open-top armored personnel carriers such as the Sd.Kfz. 251 half-track. A handguard, also made of Margolit, is located between the magazine housing and the Margolit pistol grip. The barrel lacked any form of insulation, which often resulted in burns on the supporting hand if it was incorrectly positioned. The MP 40 also has a forward-folding metal stock, the first for a submachine gun, resulting in a shorter overall weapon when folded. However, this stock design was at times insufficiently durable for hard combat use.
Although the MP 40 was generally reliable, a major weakness was its 32-round magazine. Unlike the double-column, staggered-feed magazine found on the Thompson M1921/1928 variants, the MP 40 uses a double-column, single-feed version. The single-feed insert resulted in increased friction against the remaining cartridges moving upwards towards the feed lips, occasionally resulting in feed failures; this problem was exacerbated by the presence of dirt or other debris. Another problem was that the magazine was also sometimes misused as a handhold. This could cause the weapon to malfunction when hand pressure on the magazine body caused the magazine lips to move out of the line of feed, since the magazine well did not keep the magazine firmly locked. German soldiers were trained to grasp either the handguard on the underside of the weapon or the magazine housing with the supporting hand to avoid feed malfunctions.

Usage

At the outbreak of World War II, the majority of German soldiers carried either Karabiner 98k rifles or MP 40s, both of which were regarded as the standard weapons of choice for an infantryman.
However, later confrontations with Soviet troops such as the Battle of Stalingrad, where entire enemy units were armed with PPSh-41 submachine guns, the Germans found themselves out-gunned in short range urban combat which caused a shift in their tactics, and by the end of the war the MP 40 and its derivatives were sometimes issued to entire assault platoons. Starting in 1943, the German military moved to replace both the Karabiner 98k rifle and MP 40 with the new, revolutionary StG 44. By the end of World War II in 1945, an estimated 1.1 million MP 40s had been produced of all variants.

Post-war use

During and after the end of World War II, many MP 40s were captured or surrendered to the Allies and were then redistributed to the paramilitary and irregular forces of some developing countries. The Norwegian army withdrew the MP 38 from use in 1975 but used the MP 40 for some years more. In particular, the Territorials used it until about 1990, when it was replaced by the Heckler & Koch MP5.
During the Russian invasion of Ukraine, some surviving guns saw use by both Russian and Ukrainian forces.

Variants

MP 40/I

The MP 40/I was a modified version of the standard MP 40 with a dual side-by-side magazine holder, designed for troops on the Eastern Front to counter the Soviet PPSh-41's larger 71-round drum magazine capacity. However, the design proved unsuccessful due to weight and reliability issues. In addition to the dual mag magazine well, the MP 40/I’s had a smaller buttpad, increased cutout of the receiver tubing for the larger magwell and a shortened ejector.

MP 41

In 1941, Hugo Schmeisser designed the MP 41, which was, an MP 40 upper receiver with a lower receiver and stock assembly of an MP 28/II submachine gun. It saw limited service being issued primarily only to SS and police units. The MP 41 was also supplied to Germany's Axis ally Romania.
Later in 1941, rival company Erma Werke sued Haenel, at which Schmeisser was Chief Designer, for patent infringement. Production subsequently ceased on the MP 41.

Influence on later weapons

The MP 38 and MP 40 also directly influenced the design of later weapons, including the Spanish Star Z45, the Yugoslavian Zastava M56, and the semi-automatic German Selbstladebüchse BD 38 replica.
Details of the MP 40 have also been adopted in other submachine guns, which otherwise differ significantly from a technical point of view:
  • The designers of the American M3 "Grease Gun" examined British Sten guns and captured MP 40s for usable construction details.
  • The folding stock became the model for those on later weapons, such as the Soviet PPS-43 and the AKS version of the AK-47.
  • The MP 40 magazine can also be used in the Belgian Vigneron submachine gun.

    Users

During World War II, the resistance and the Allies sometimes captured MP 40s to replace or supplement their own weapons. The MP 40 was used for several decades following World War II by many countries around the world in armed conflicts. Some found their way into guerrilla groups such as the Viet Cong or African guerrillas.
Its operators have included:

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