Sten magazines were based on the Lanchester SMG because the Lanchester was in production already. The Lanchester in its turn was based on the Germanicon MP28, thus magazines also. MP38/40 magazines in turn were based on the MP28 magazines as production existed. In theory [and practice?] the Sten magazines should be able to use MP38/40 magazines. The Sten magazines were used as the basis for the US M3 SMG?
Is my reasoning correct?