I read somewhere that when Krupp was barred from operation after WW 2 had ended, the only weapon that escaped the net was this 20mm MG 151, which had been the standard 20mm gun for the Luftwaffe, so a new company called Rheinmetall was formed and the family who owned it touted the gun around the world,using examples saved from the bombed out factories and salvaged from wrecked aircraft. For some reason, it wasn't included in the production ban but could be built outside Germany and it is still in widespread service to this day.