Send the pics and let's see what you have. I'd guess Robert possibly was a brother to Richard. Post Lindner/1915 Dalys were coordinated by one of the Schüler's and I want to say it was Richard but I'll have too look. In 1927 Heimbeck may have tapped the frame for the engraving but a pic would reveal more info. I think Robert Schüler offered some big bore DRs and from that I'd say he had to be closely associated with Richard Schüler as there were big bore cartridges by the Krieghoff-Schüler team. Also Sempert & Krieghoff was sourced by Richard Schüler for examples so your drilling just may be by Heinrich Krieghoff. Some sources give the following for Schüler firms being founded and I would assume they attained the rank of master at the same time or just prior:
Friedrich Schüler - 1835
August Gottlieb Schüler - 1850
Oscar Schüler - 1880
Richard Schüler - 1912

Below is some info on August Schüler, who had some sort of ammo factory or store front for an ammo factory named Mechanische Waffen-u-Munitionslfabrik. I can't say they made ammo but the possibility exits and it might have been the experimental ammo shop.

In 1935 there was an advertisement noting that August Schüler had been in business for 100 years. Of course it is not possibly for the same August Schüler that we associate with German longarms to be that person and he took the reins of a company circa 1850 and the name could have been “August Schüler”(or renamed to) as he was the younger brother of Christian Friedrich Schüler who indeed did have a gunmaking business in 1835 and some accounts give the name Friedrich Wilhelm Schüler. Friedrich Schüler was also a gunmaker but had not earned his brief by 1840. Christian Friedrich Schüler was listed as having a manufacturing facility and also fabricated pickles or vinegar. Possibly their father or grandfather was named August Schüler and Christian Friedrich’s business was named “August Schüler” or either August Gottlieb Schüler took over the business and renamed it circa 1850. Circa 1900 Friedrich Schüler and his son Oskar were running the business, which was turned over to Oskar just before WWI. By this time Oskar’s son Richard was in the family business. But using the same name of Friedrich Schüler over 100 years really does complicate things. Also in 1880 there was a gunmaking business founded by Oscar and August Schüler and I think this was the same company that Friedrich Schüler, Oscar & Richard Schüler ran.


Kind Regards,

Raimey
rse