An old photo of the Sauer hammer forge is shown in their 1924 catalog, perhaps in others as well, but I have a copy of that one. The recent book by Arfman and Kallmeyer on J P Sauer states that in the early 1940's, at the peak of their output, the J P Sauer factory complex extended over 52,000 sq. meters, some 12.85 acres if the Google converter is accurate. Early GGCA materials on Simson indicate that in the 1924-34 period their complex extended over 25 acres. Simson was located on a river, so power was available, they were twice the size of Sauer at a time 15 years earlier, who knows how they may have grown to the same date used in the Sauer mention, so why would one not expect them to also have a hammer forge? That's certainly not proof that they did, but I tend to think they did. I'll look further as I have more time. I don't think we can rule out the largest gun maker in Europe having their own forge. I can post the Sauer forge photo as well a tad later.
