The Erma-Panzer 58, also known as the "Smart", was a grenade-launching submachine gun designed by German firearms manufacturer Erma Werke.
The Erma-Panzer 58 was designed in the late 1950's. It was a joint design between Erma Werke and another unknown collaborator, with the emphasis on creating a multi-purpose weapon that could be deployed both as a submachine gun and a light anti-tank weapon. The submachine gun itself fired from a closed bolt and was chambered for 9x19mm Parabellum ammunition. It could use MP-40 magazines. The prototype Erma-Panzer 58 models were tested at the Bundeswehr Training Centre at Meppen, where it reportedly performed well, firing grenades at over 100 meters. Despite this, the Bundeswehr showed no official interest in the weapon and it was not adopted or developed past prototype stages. A similar submachine gun was developed by Mauser in the early 60's, known as the Mauser Model 60. It too had grenade-launching capabilities.