Manufactured 1955-1958, the ZFK31/55 is a derivative of the K31 rifle configured for precision long range shooting that is complete with its matching 3.5X sniper scope. Reportedly 4,150 were produced in total. Blade front and tangent rear sights, with a combined flash hider and bayonet lug unit integrated into the sight, "Swiss Cross and Shield" engraved on the receiver ring, and a set of integrally forged scope bases on the left side of the receiver. Matching serial numbers are present on the barrel, receiver, bolt, magazine and the scope, with the magazine also marked out "Zf.Kar.", denoting use with a scoped rifle, and the scope marked "KERN AARAU/V=3.5/(view angle symbol)=75 0/00". The scope is fitted with a set of integral claw bases, with a three-post reticle. Smooth pistol grip stock, with a folding bipod just ahead of the magazine well, forearm grooves, checkered wrist, brown leather sling and a flat buttplate. Included with the rifle is a "55" marked spare parts kit, an adapter screw for installing a Harris-style bipod in lieu of the current model, and a matching numbered scope case.