Allan:
Scratch the E. Schmidt & Habermann guess for a moment. For circa 1914, the "RM" just might be for Ernst Richard Meffert, owner of Immanuel Meffert. Can you post a pic of the top of the frame and top strap? Is the word "Treff" or "D.R.G.M." atop it? Yes, E. Schmidt & Habermann was a maker to the trade and as evident by the initials on your example pretty much Suhl & Zella-Mehlis was one big gunshop and firearms merchants sourced the whole of both.

Kind Regards,

Raimey
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