The fourth model Winchester mold was the first mold made of iron. In general configuration, it appeared quite similar to the brass/bronze third model mold. The first, third and fourth model Winchester molds did not have wooden handles. The ends of the handles on the fourth model mold are smooth, not threaded like those seen on the fifth model. One finds a few fourth model molds with no mark other than an apparently hand-stamped caliber marking made with relatively small sized numbers. Those are thought to be early examples. They usually have no block alignment pin either. Later subvariants include 1) molds with uniform caliber stamps, no block alignment pins and no Winchester stamping; 2) molds with Winchester markings, uniform caliber stamps, but no alignment pins; 3) molds with uniform caliber stamps, Winchester markings and alignment pins; 4) molds with markings from other companies. Most likely, the hand-stamped molds with no Winchester markings and no alignment pins were the earliest production. Those were probably followed by molds which were stamped with especially made caliber stamps; the next "improvement" appears to be addition of the Winchester name. Addition of the block alignment pins probably followed with latest examples showing nice, uniform caliber markings, the usual Winchester name stamp, and block alignment pins. Here is an image showing the 4 variations of fourth model iron mold; all in 45-60 caliber.