 The Maschinenpistole 40 ( " Machine pistol 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 ( Army Weapons Office ) for a new submachine gun , which was adopted as MP 38 . 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 . 
