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 some recently being imported into the United States. This model has a heavily reinforced blade front sight with integral flash hider/bayonet lug, with a tangent rear sight marked 1-15. These rifles feature a straight pull type action with the chamber area marked with the standard Swiss Cross inside a Shield. This model has the integral scope mounting points with the 3.5 sniper scope attached. The top of the scope body is marked "3135 Kern Aarau/V=3.5x75". These rifles were all fitted with a beech stock and handguard with a checkered pistol grip area with a sheet metal buttplate. The stock has a front folding sheet metal bipod and side mounted leather sling. This rifle includes a green painted metal belt carrier numbered to match the scope. The underside of the barrel is dot-matrix marked "ZFK31/55 SWISS 7.5MMX.55 OOW INC. CHARDON OH."

Very fine with 75% of the arsenal matte blue finish. With areas of edge wear, some soft edges on the receiver, light spotting on the front barrel band and general handling marks on the bolt handle. The wood is very good with scattered dings and indentations throughout, moderate to heavy scratches and general handling marks. Mechanically very good. Optics are clear. Scope can is very good with light scratches and edge wear.