Forearm cap OCTAGON barrel Winchester 94 POST 64 Buffalo Bill Edition ORIGINAL wINCHESTER PART. This Forearm cap is for an octagon barrel and is nickel platted. It holds the forearm wood on to the rifle with the OCTAGON barrel. This is different from the pre 64 1894 in that the screws attach to the tenon (part number C135) from the front and not the side.