This is a late carbine with 1873 Breech block ,  cartouche is 1886 and it has the Buffington rear sight and front sight cover.  Both the front sight cover and rear sight were new for 1886. Left side has clear Sam Porter stamp and P under wrist.  Stock is excellent with no cracks or chips.  Most of the barrel blue has started to plum  while trigger guard retains most of the fire blue finish. Block and lock are dark gray and butt plate has turned patina.  bore is excellent and shiney and gun locks up like new. One of the last 73 carbines with all the 1886 updates.