Raimey;
I have a Waffen-Frankonia catalog (The Hunter's Counselor) dated 1964. In it the Sauer models Kim & Royal dbls & the model 3000/3000 Delux drilling all are stated to have bbls made from Special Steel, "Bochumer Verein". Drilling DUR has a "Light Metal Action, Drilling ANT has bbls of Boehler Antinit NG & DURANT has a combination of the later two.
The Simson shotguns/drilling listed simply state "Special Steel".
On the steel specs page is also listed a steel know as "Boehler Special" so hard to say positively from this catalog just what steel the Simson used.
I do not recall seeing anything listed in this catalog with Krupp.
