Long action Remington factory detachable bottom metal. Came out of a .270 and has 2 magazines. Only one I've run across, so I have no idea what it's worth. $175 shipped
Score! I have one of these from a 7mm rem mag that I have been hanging on to for some day building a short action mag on a long action. They are really nice, although a bit short to take advantage of COL.