This Thompson Center manufactured late variation rib is for the Scout in-line muzzle loading carbine and mounts on the underside of the barrel between the barrel and ram rod.  This rib is in very good condition with light wear. The late variation rib uses two thimbles instead of only one like the early variation Scout carbines.  (file photo)

Note: Thompson Center Scout muzzle loading carbines with the following serial numbers have been observed with this part: 3474, 16260 & 40046