This is an unusual U.S. Cavalry S.A. serial number is 115992 with Casey marked butt with G below serial number and made in 1885. Matching DFC barrel but the cylinder is 5599, DFC and was most likely mixed up during a blanket cleaning. (393 numbers apart) The right grip panel has GA and left is FH for Captain Frank Heath and bottom of the grip has DFC. The frame is DFC and also a L stamped over the DFC. The trigger guard has a G also. There is nice blue under the ejector housing and blue on the right and left side of the ejector housing. There is blue in the cylinder flutes. The mechanical function is very good and the bore is very good, bright and shiny. Someone scratched AH on the butt below the serial number. This needs to be researched. John Kopec and Sterling Fenn book sheds a little light on these Colt Cavalry revolvers.