Ken, I have since checked a total of 15 other Suhl proofed guns from the same general period, by Sauer, Merkel, Simson, and Fischer. I didn't bother checking a few Zella Mehlis proofed guns. I have two more Simson guns that bear the same "F.A." mark, a 12 gauge SxS dated 138, (it's listed for sale and pictured elsewhere on this site) and a 16 gauge O/U gun dated 137. So, whoever your guy is, he definitely had a relationship either with Simson or the Suhl proofhouse for some period of time, at least nine years total.
