An elongated product is formed such that first a core is formed, the outer surface of the core being made of plastic. Thereafter, a tubular metal layer is extruded such that the layer is seamless. When the metal layer is extruded, a clearance (16) is allowed between the metal layer and the core. After the metal layer has cooled, the outer surface of the core is arranged against the inner surface of the metal layer. An adhesive action is arranged between the core and the metal layer and a permanent compressive force is arranged, which compressive force compresses the core and the metal layer together.