|"This weapon isn't functioning properly! Send it back to the armory and perform the necessary repairs to make it functional again."|
The MP 40 (machinepistole 40) was a Submachine gun made and used around the World War II period. It is one of the most famous and iconic submachine guns of World War II, the MP 40 was the primary Submachine gun of the German Wehrmacht between 1940 and 1945, mainly due to its extreme ease of use, reliable automatic rate of fire, and cheap and widespread production.
The MP 38 submachine gun started its life under requirements from the German Heereswaffenamt (HWA, Army Weapons Office), which saw the need for a compact submachine gun, suitable for use by armored vehicle crews and paratroopers. The German arms-making company Erfurter Maschinenfabrik Gmbh, better known under its trade name Erma, began the development of a new weapon under HWA specifications.
It must be noted that the new submachine gun was not built from the scratch; instead, it was just an evolution of a rarely known prototype weapon, provisionally known as the Erma MP 36. The MP 36 was a compact version of the better known Erma EMP submachine gun, but fitted with the now-familiar underfolding metallic shoulder stock and bottom-feed magazine, which was slightly canted forward to accommodate EMP magazines.
The MP 36 was a select-fire weapon, and in fact the improved MP 38 was a simplified version of its little known predecessor, adapted for different magazine. Therefore, it took only few months before the new weapon was ready for official adoption and mass production. The manufacture of the new submachine gun, designated as the MP 38, commenced in the summer of 1938, at Erma, and later on also at C.G. Haenel.
The gun was manufactured for just 2 years, before it was replaced in production by the externally similar, but less expensive MP 40, which used more stamped parts instead of the machined parts found in MP 38. There were also minor variations in the design of the MP-38, such as the shape of the charging handle etc. The MP 40 was also produced in a number of variations, which differed mainly in the shape of certain parts; also, towards the end of the war, several production shortcuts were introduced to save the costs of manufacturing.
Probably the most interesting variation of the MP 40 were the MP 40/I and MP 40/II. These guns featured dual magazine housings which hold two magazines in a laterally sliding bracket. This increased the total ammunition capacity "in the gun" to 64 rounds, in a desperate attempt to catch up with the 71-round magazine capacity of the Soviet PPSh-41. The later variant, MP 40/II, was made in limited numbers, but turned out to be a failure - the sliding dual-magazine housing was a constant source of jams and failures, and was very sensitive to dirt and fouling.
Nevertheless, MP 38 and especially MP 40 submachine guns were of good design, and set the pattern for the so called "second generation" of submachine guns ("first generation" being represented by the wood-stocked and carefully machined MP 18, MP 28 and the like). The second generation weapons usually were of compact design, and made using mostly steel stampings and pressings, or castings.
It should also be noted that many MP 40s survived WWII. These weapons continued to serve up until the late 1970s or early 1980s in a few European armies, such as the Austrian or Norwegian armies.
Both the MP 38 and the MP 40 submachine guns were blowback operated weapons that fired from open bolt. Both weapons were full-automatic only, but the relatively slow rate of fire permitted for single shots with short trigger pulls. The proprietary bolt system with telescoped return spring guide served as a pneumatic recoil buffer, helping to decrease rate of fire to a very manageable level. The bolt handle was permanently attached to the bolt on early MP 38s; on late production MP 38s and MP 40s, the bolt handle was made as a separate part and also served as a safety - pushing the head of the bolt handle inward locked the bolt either in cocked or forward position. The lack of such feature on early MP 38s resulted in field expedients such as leather harnesses with a small loop, used to hold the bolt in the forward position.
One unusual feature on most MP 38 and MP 40 submachineguns was an aluminum or plastic rail under the barrel, which served as a barrel support / protector when firing over the board of an armored personnel carrier. The short handguard was made from plastic and was located between magazine housing and pistol grip; barrel lacked any heat insulation, which often caused burns for supporting hand. Folding shoulder stock resulted for compact weapon when folded, but it was insufficiently durable for combat use and hand-to-hand combat. Single-feed, double-row box magazine was another weak point of the design; it was hard to load without additional help, and often caused jams.