Probably >>F.A.<< or less likely >>E.A.<< and >>F.A.<< is quite common forward on the flats on doubles post WWI. If >>F.A.<< then maybe Franz Adamy or if earlier in time, Friedrich Adamy. There really aren't that many A family Büchsenmacher families but if not Adamy, then maybe Albrecht & Anschütz(those few from Suhl). I will ponder a bit on it.

Serbus,

Raimey
rse