This is an Original Springfield 45-70 Carbine top Butt Plate screw. Shorter than normal screw length. Fine overall condition. This type of Top butt plate screw was used on all carbine models except the early 1873 with out the cut out for the cleaning rods. It was used on later Model 1873, 1877, 1878, 1879, 1884 Springfield Carbines.