Collectors and historians are familiar with the Russian “Tractor Cap” or “Snow Cap” Maxim machine gun. It was a modification of the PM1910 (Pulemyot Maxima na stanke Sokolova or “Maxim’s machine gun Model 1910 on Sokolov’s mount”) that did away with the small water filler hole in the water jacket and instead a much larger hole was cut into the top of the water jacket that allowed snow, ice or larger volumes of water to be introduced quickly into the water jacket. The hole was covered by a tractor radiator cap that was hinged on one side and secured by a clasp on the other side…