Vollmer began his manufacturing career by making parts for the German copies of the Maxim gun during the First World War.

It was followed by a somewhat similar device for the MP/18/I submachine gun—this consisted of a 60-round circular, spool magazine that was carried by the soldier on loop on his hip and it was connected to the gun by a flexible hose.

(The Reichswehr was prohibited by the Versailles Treaty from having sub-machine guns in service, although the German police was allowed to carry a small number.)

Secret funding was given to Vollmer to continue development, and this resulted in the VMP1926, which mostly differed from its predecessor by the removal of the cooling jacket.

In late 1930, the Reichswehr stopped supporting Vollmer financially; consequently he sold the rights to all his designs to the company known as Erfurter Maschinenfabrik (ERMA), which continued development as the EMP.