Almost nothing is known about Robert Scheer of Sommerfeld near Frankfort on the Oder. He seems to have been a somewhat inventive gun maker. On june 15, 1895 he was issued D.R.G.M. no. 42590 for a pop up sight. An interpretation of the D.R.G.M. reads- Sighting apparatus for Drilling-Hunting Rifles where the sight is adjusted with a U shaper push rod next to the top rib.

An advertisement from the Sept. 24, 1893 paper Deutsches Jäger Zeitung