MP 40 / MP 38

MP-38 submachine gun.
MP-38 submachine gun.

 MP-40 submachine gun, with shoulder stock folded.
MP-40 submachine gun, with shoulder stock folded.

MP-40 submachine gun, with shoulder stock opened.
MP-40 submachine gun, with shoulder stock extended.

MP-40-II submachine gun, with sliding dual magazine housing (see insert).
MP-40-II submachine gun, with sliding dual magazine housing (see insert).


Specification Value
Full text name MP 40 / MP 38
Caliber cartridge 9mm Luger - 9x19 Luger / Parabellum
Action type manual
Trigger type sa
Overall length, mm 833
Length, folded, mm 630
Weight empty, kg 4.03
Weight loaded, kg 4.7
Magazine capacity, rounds 32
Cyclic rate of fire, rounds/min 400-500

The MP38 submachine gun was created after 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.

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 scratch; instead, it was just an evolution of a rarely known prototype weapon, provisionally known as Erma MP36. MP36 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 the EMP magazines.

MP36 was a selective-fire weapon, and in fact the improved MP38 was a simplified version of its little known predecessor, adapted for a different magazine. Therefore, it took only a few months before the new weapon was ready for its official adoption and for mass production. The manufacture of the new submachine gun, designated as MP38, commenced in the summer of 1938, at Erma, and later on also at C.G. Haenel und Fahrradfabrik, Suhl.

MP38 was manufactured for just 2 years. Then it was replaced by the externally similar, but less expensive to produce MP40, which used stamped parts in place of the machined parts as found in the MP38. There were also minor variations to the design of the MP38, such as the shape of the cocking handle and similar minor details.

The MP40 was produced in a number of variations, which differed in the shape of certain parts. Also, towards the end of the war, several production shortcuts were introduced to save costs during manufacture.

It was sometimes erroneously called the “Schmeisser” submachine gun and though Hugo Schmeisser did work at Haenel, he did not have a hand in designing the weapon. Heinrich Vollmer was the designer, having sold the patent to ERMA.

Probably the most interesting variation of the MP40 was the MP40-II. These guns featured dual magazine housings which held 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 MP 40-II was made in limited numbers, but turned out to be a dud. The sliding dual-magazine housing was a constant source of jams and failures, and was very sensitive to dirt and fouling.

Nevertheless, MP38 and especially MP40 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  were usually of a compact design, and made using steel stampings and pressings, or castings instead of complex machining.

It  must also be noted that many MP40’s that survived World War 2, continued in service up until the late 1970’s or early 1980’s, in a few European forces such as the Austrian or Norwegian Armies.

Technical Description:

Both MP38 and MP40 submachine guns are blowback operated weapons that fire from an open bolt. Both weapons were fully-automatic only, but a relatively slow rate of fire permitted single shots with short trigger pulls. The proprietary bolt system with telescoped return spring guide served as a pneumatic recoil buffer, helping to decrease the  rate of fire to a very manageable level. The bolt handle was permanently attached to the bolt on early MP38’s.

On late production MP38’s and MP40’s 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. Lack of such a feature on early MP38’s resulted in field expedients such as leather harnesses with a small loop, used to hold the bolt in a forward position.

One unusual feature on most MP38 and MP40 submachine guns 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 the magazine housing and pistol grip. The barrel lacked any heat insulation, which often caused burns for the supporting hand.

The folding shoulder stock resulted in  a compact weapon when folded, but it was insufficiently durable for combat use and hand-to-hand combat. The 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.