This is a hard one to find today.  It is an original cylinder, which would be appropriate for a 2nd or 3rd Model Colt Dragoon.  It is a military parts cylinder.  Even though it has deteriorated somewhat, it is not serial numbered and has never been mounted on a gun.  With every military contract Colt filled, there was a large number of unnumbered parts, which went with it.  They were for the purpose of maintaining the guns in the field.  This is one of those unnumbered cylinders.  Typically, there is a star stamped on the face of the cylinder, sub-inspector marks on the circumference of the cylinder and a "P" sub-inspection at the rear.  You will note that the face of the cylinder still has its finish marks and the safety pins at the rear are fully intact.  Between the two cartouches on the cylinder, there is a single part number stamped, there is not a serial number.  This cylinder was a part of the Third US Contract and as such is appropriate for a 2nd or 3rd Model Dragoon.  The upper cartouche bears the words "U S Dragoons" not Model USMR.  The first US Contract, which was the Colt Walker and the second US Contract, which was the Fluck Dragoon had cylinder scenes marked Model USMR in the upper cartouche.  The reason for that was that both contracts went to the 1st Regiment of United States Mounted Rifles.  The third contract was initially for the Second Regiment of US Dragoons, which was stationed in Texas.  In order to keep the regimental association on the Third US Contract, they  spliced the die that rolled the cylinder scene.  They made an elliptical cut and removed the model USMR, replaced the metal and recut the die to roll the impression "US Dragoons."  I assume that the Third Contract  was extended because very soon, the relationship of the marking on the cylinder and the regiment to which the guns were to be issued was lost.  You can find these US Dragoon marked cylinders on both 2nd Model and 3rd Model Dragoons and they appear to intermixed with those marked Model USMR.  This cylinder still has a very good cylinder scene with an Ormsby signature and Colt Patent in the lower cartouche.  I used to find these old Colt military parts fairly frequently but they don't turn up much anymore.  SOLD!!