The Maschinenpistole 40
The MP40 Maschinenpistole, or Machine Pistol is probably the quintessential submachine gun of World War 2, developed in pre war Germany and was used extensively by Luftwaffe paratroopers, Panzer and armoured vehicle crews, Officers and NCO squad leaders, and other specialist troops during World War 2.
The MP40 was descended from its predecessor, the MP38, which was in turn, based on the MP36, an early prototype made of machined steel. The German arms manufacturer Erma Werke developed the MP36. It took design elements from Heinrich Vollmer's VPM 1930 and EMP. Vollmer himself then worked on the MP36 and in 1938 submitted a prototype to answer a request from the German ‘Heereswaffenamt’ Armaments Ministry for a new submachine gun, which was adopted as the MP38.
In essence, the MP38 was a simplification of the MP36 prototype, and the MP40 was a further simplification of the MP38, with cost-saving alterations, such as extensive use of stamped rather than machined parts. The receiver was originally machined steel, but this was a time-consuming and expensive process. This prompted the development of a simpler version that used stamped steel and electro-spot welding as much as possible. The MP38 features are easily recognisable with longitudinal grooving or ribbing on the receiver, as well as a circular opening cut into the magazine housing. Some of these features were deleted in the MP38/40 and totally in the MP40 incarnation, for a smooth sided stamped steel receiver, but with the ribbing feature appearing on the magazine housing instead. Other changes resulted from experiences with the several thousand MP38s in service since 1939, which had been used in action during the invasion of Poland. These changes included a much improved safety catch as the early MP38’s often suffered from being accidentally discharged, injuring many soldiers.
Both the MP38 and MP40 submachine guns operated by an open-bolt, blowback system. Full automatic fire was the only setting, but the relatively low rate of fire and recoil allowed for 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 MP38s, but on late production MP38s and MP40s; the bolt handle was made as a separate component. It also served as a safety by pushing the head of handle into a separate notch above the main opening; this locked the bolt either in the cocked rearward or a closed forward position.
A Bakelite hand guard was located between the magazine housing and pistol grip. The barrel lacked any form of insulation, which often resulted in burns for the supporting hand if it strayed. It also had a compact folding metal stock, the first for a submachine gun, resulting in a shorter weapon when folded, but it was at times inadequately robust for hard use in combat.
Although the MP40 was generally reliable, a major weak point was its 32-round magazine. Unlike the Thompson's double-column, dual-feed magazine, the MP38 and MP40 used a double-column, single-feed design. The single-feed resulted in increased friction and pressure against the remaining cartridges moving upwards towards the feed lips, occasionally resulting in a failure to feed. Another problem was that the magazine was also sometimes misused as a handhold, which 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 intended handhold on the underside of the weapon or the magazine housing with the supporting hand to avoid feed malfunctions.
The MP40 was often called the "Schmeisser" by the Allies, after weapons designer Hugo Schmeisser. Schmeisser had designed the MP18, which was the first mass-produced submachine gun, and saw extensive service at the end of the First World War. He did not, however, design the MP40, although he held a patent on the magazine. He later designed the MP41, which was an MP40 with a wooden rifle stock and a selector, identical to those found on the earlier MP28 submachine gun. The MP41 was not introduced as a service weapon with the German Army, but saw limited use with some SS and police units. They were also exported to Germany's ally, Romania. The MP41's production run was brief, as Erma filed a successful patent infringement lawsuit against Schmeisser's employer, Haenel.
Early in the war MP40s were generally issued only to specially selected personnel; the majority of German soldiers carried Karabiner 98k rifles. However, later experience with Soviet tactics, where entire units were armed with PPsh41 submachine guns often outgunned their German counterparts in urban combat. This consequently caused a shift in German thinking and tactics, and by the end of the war the MP40 and its derivatives were being issued to entire assault squads on a limited basis. Despite this policy and with just over 1 million examples of all versions being produced during the war, there were never enough MP40s to go around, simply because raw materials and labour costs made it expensive and slow to produce alongside the Kar98 rifles. As a result in 1943, the German army moved to replace both the Kar-98 rifle and MP40 with the new integrated assault rifle the StG 44.
After the Second World War, many of the MP40's that were captured by the allies were sold as surplus weapons to many developing countries, paramilitary and irregular forces where they often ended up being used on battlefields in places such as Africa and Israel. They were even used by the French Army in Indochina and later by the US Special Forces who took them in small quantities to South Vietnam as well, the latter who probably collected the weapons from their West German bases.