Having taken a close look at this original Erma EMP submachine gun yesterday, we are out at the range with it today. Like several of the interwar SMGs, the Erma was designed with a magazine well long enough to accommodate 9mm Steyr (9x23mm) ammunition, and it was offered in several different calibers. The 9mm Parabellum magazines have a spacer at the rear to hold the rounds forward for proper feeding.

In addition to Erma production, the EMP was copied by the Spanish La Coruña arsenal in the 1940s. Spanish magazines are readily available, and I am curious to see if they will work in a German EMP...