I agree the gun was Marketed by Burgsmueller& Sohn, proofed in Suhl sometime between 1911/12 and 1922/23. It was reproofed in Zella Mehlis in 1943. The 9.3x72 and 16.65 stamps are problematical. They don't seem workmanlike enough to be from the proofhouse, I wonder if they were placed there by an owner. The 8.8 is consistent with other Suhl proofs from 1911/12(later they added case length). It was reproofed under the 1939 law which required caliber designation in common use form.
Mike