Fritz Kühner, Breite Strasse 4, Stettin, is documented from 1888 to 1898.
Krupp was not the first to offer Gussstahl = cast steel small arms barrels. They came into this market only in the 1890s, but already had a "name" for their fame as cannon makers since the Franc-Prussian war 1870-71. The use of cast or fluid steel for rifle barrels was pioneered by Berger's steelworks in Witten on Ruhr, a competitor of Krupp. The Prussian army used Witten cast steel barrels on their Dryse needlefire rifles since 1863. In the 1870s the Witten steelworks dominated the world market in barrel steel, exporting huge amounts. One of their main US customers then who bought not only standard dimensions,but also special ordered 2" bar stock, was Colt in Hartford, Conn. So your "All American" 1873 Colt peacemaker most likely has a barrel and cylinder made of German Witten Gussstahl.
