Apart from the proofmarks under the barrel, please post also photos of the "Heym" inscription. The proofmarks will show us the date or, at least, if before 1912. Over the years, no less then 60 gunmakers named "Heym" were active in Suhl, Friedrich Wilhelm, the predecessor of the today "Heym" company in Gleichamberg being only one of them. The AH-suffix serial number rather points to another Heym, maybe August (2), Albert, Adolf (3), or another.