Could easily be KS, where the highest probability is associated w/ Karl Streng....

"R.S. – Robert Schlegelmilch until 1923 and the possibility of Richard Schüler thereafter

E.E. – Emil Eckholdt beginning in 1876, at some point used “EES”- Emil Eckholdt Suhl

K.S. - Karl Streng & Company of Goldlauter

Suhler Waffenfabrik Schlegelmilch & Metzner existed until 1901 and then Suhler Waffenfabrik Robert Schlegelmilch was formed and existed until 1923. Seeing Robert Schlegelmilch examples in the 1912-1923 period suggest that he was active during this period and Daly doubles with proof dates in 1924 just might be his work. He did source the tube making to the Kelber boys as did many others during this period mainly due to economics. Post 1923 the possibility exists that the "R.S." initials could easily be for Richard Schüler seeing there is documentation that links Schoverling, Daly & Gales with Richard Schüler."

"All of these H.A. Lindner subcontractors, including Karl Streng & Co., seemed to be specialists in the field of tubes, tube harmonics, etc. & that the term "Mehrlaufgewehre", or multi-barrel weapons, is associated w/ their name. Then again, what else would expect concerning H.A. Lindner as he would not have applied his Quality Control Stamp to his wares had it not have been so. And Charles Daly assumed so....."