Here is clearly to see, that the Stendebach IDEAL bullet had only 2 inside Rotors to bring the slug to spin. Front has raised markings of Company and caliber and the Name IDEAL mentioned…
And the STENDEBACH IDEAL was a protected Name (Eingetragene Schutzmarke)
Sidemarks on the box are “Für Würgebohrung” and the other side : Für Zylinderbohrung"
means ist good for “choked Barrels” and for “/Zylinder bore” = Barrels without choke
See pics. BOX:
sideview of slug:
And front and base of Slug: