MP40

From Metapedia

The MP40 (Maschinenpistole 40, literally "machine pistol 40") was a submachine gun developed in Germany and used extensively by paratroopers and platoon and squad leaders, and other troops during World War II. The MP40 had a relatively low rate of fire and low recoil, which made it more manageable than other contemporary submachine guns. The MP40, and its predecessor the MP38, were sometimes referred to by the Allies as "burp guns".

[edit] History

The MP40 is descended from the MP36, a select-fire prototype made of machined steel, of which only two examples remain. The MP36 prototype was developed independently by Erma prior to the 1938 request from the German government for a new submachine gun which led to the MP38. The MP38 was a simplification of the MP36, as the MP40 was later a simplification of the MP38, the differences being in cost-saving alterations, especially the use of more pressed rather than machined parts and an improved safety.

The changes resulted from experiences with the several thousand MP38s (in service since 1939) used during the invasion of Poland. The changes were incorporated into an intermediate version (MP38/40), and then used in the initial MP40 production version. Just over 1 million would be made of all versions in the course of the war. The designer of the MP38/40 was Heinrich Vollmer.

The MP40 was often called the Schmeisser by the Allies, after weapons designer Hugo Schmeisser. Although the name was evocative, Hugo Schmeisser himself did not design the MP40, but helped with the design of the MP41 which was effectively a MP40 with an old-fashioned wooden rifle stock. The earlier MP18 submachine gun had been designed by Schmeisser and did carry that name.

[edit] Design

Both MP38 and MP40 submachine guns are open bolt blowback operated automatic arms. Full-automatic fire was the only setting, but the relatively low rate of fire allowed for single shots with controlled trigger pulls. The bolt features a telescoped return spring guide which serves as a pneumatic recoil buffer. The cocking handle was permanently attached to the bolt on early MP38s but on late production MP38s and MP40s bolt handle was made as a separate part. It also served as a safety by pushing the head of handle into a separate notches above the main opening which locked the bolt either in the cocked or forward position. The absence of this feature on early MP38s resulted in field expedients such as leather harnesses with a small loop, used to hold the bolt in forward position.

The receiver was originally machined steel but this was a time consuming and expensive process. This prompted the development of a simpler version which used pressed steel and electro-spot welding as much as possible. The MP38 also features longitudinal grooving on the receiver and bolt, as well as a circular opening was on the magazine housing. These features are deleted on the M38/40 and MP40.

One idiosyncratic and visible feature on most MP38 and MP40 submachine guns was an aluminum or plastic rail under the barrel which was handy as a support when firing over the side of open top armored personnel carriers such as the Sdkfz 251 half-track. A handguard was located between magazine housing and pistol grip and was made from plastic. The barrel lacked any form of insulation such as a barrel jacket seen on the MAB38 or Sten, which often resulted in burns for the supporting hand if it strayed. It also had a folding stock, the first for a submachine gun, resulting in a more handy weapon when folded, but it was insufficiently durable for hard use and hand-to-hand combat.

Though the MP40 was generally reliable, a major weak point of the MP38 and MP40 was its 32-round magazine, a weakness inherited by the British Sten which copied the same design. Unlike the Thompson's double-column, dual-feed magazine, the MP38 and MP40 used a 'single-feed' design. With the single-feed design, a double column of cartridges narrowed to a single-cartridge width at the feed end of the magazine. This meant that the 9 mm cartridges had to overcome increased friction in order to reach the chamber, as well as requiring a loading device to fill the magazine to capacity.

The design was also sensitive to dirt and debris. German soldiers soon learned to give the magazine a sharp slap to restore operation. The magazine was also frequently misused as a handhold, which could also cause a failure to feed when hand pressure on the magazine body caused the feed lips to move out of position. German soldiers were trained to grasp either the intended handhold on the underside of the weapon or the magazine housing with the supporting hand (not the magazine itself) to avoid feeding malfunctions.

Unlike the impression given by popular culture, MP40s were generally issued only to paratroopers and platoon and squad leaders; the majority of soldiers carried Karabiner 98k rifles. However, experience with Soviet Union tactics where entire units armed with submachine guns out-gunned their German counterparts in short range urban combat caused a shift in tactics and by the end of the war it was being issued to entire assault platoons on a limited basis.