Introduced in the mid-1950s, the ZFK31/55 is a derivative of the K31 rifle configured for precision shooting with many of the parts changed towards that end. Approximately 4,150 were made with an unknown but small quantity making it onto the American market. Heavily reinforced drift adjustable blade front sight with integral bayonet lug and flash hider and a tangent rear sight with Swiss Cross marked chamber, integral scope mounting points and matching numbers on the bolt and "Zf.Kar." magazine. Mounted on the frame is a Kern Aarau 3.5x75 scope numbered "1864". Checkered pistol grip stock with a flip-down metal bipod, brown leather sling, and a smooth buttplate. Included with the rifle is a green painted metal belt carrier numbered to match the scope.

Fine with 75% of the original blue finish. Showing a mixed gray and plum brown patina on the flash hider assembly, bright edge wear, a gray patina on the handguard collar and mild handling marks and spotting overall. Import marks on barrel. The stock is good with braized repairs to the forearm cap, scuffs and dents. Optics are clear. Mechanically excellent.