A quick google search turned up year of production of your Colt Navy revolver as somewhere between 1851 and 1852(Serial numbers 2,500-10,000). You may be able to find original parts through Dixie Gun Works. Possibly also, Numrich Arms. Another useful site may be VGP Western parts(vgpwestern.com). Also, the Yankee Collector (yankeecollector.com) I have not dealt with either of these companies. But, these may turn up some useful leads. I wouldn't discount contacting Taylor Firearms. Pietta revolver parts are often a very close match to original Colt mfg. There is also Peter Dyson, in the U.K.(peterdyson.co.uk) This one is a bit of a stretch, but worth looking into, at the very least. Hope some of this helps.