 However , later experience with Soviet tactics , such as the Battle of Stalingrad where entire Russian units armed with submachine guns outgunned their German counterparts in short range urban combat , caused a shift in tactics , and by the end of the war the MP 40 and its derivatives were being issued to entire assault platoons on a limited basis . Starting in 1943 , the German Army moved to replace both the Karabiner 98k rifle and MP 40 with the new , revolutionary StG 44 . By the end of World War II ( which ended in 1945 ) , an estimated 1 @.@ 1 million MP 40s had been produced of all variants . 
