This Springfield Armory manufactured early variation cam latch screw (aka breech block cap screw) is for the early model 1873 trapdoor rifle and carbine and is in very good condition exhibiting a grayish brown patina with light slot wear.  (file photo)

 Note: Trapdoor rifles and carbines with serial numbers below circa 87,000 would have used this early variation screw having the sharp edge (not beveled) on the radius of the head.