bought a JM Caswell smooth rifle and have questions

[adkmountainken]

just bought a JM Caswell .50 smooth rifle today. has a few issues and a couple replacement parts but overall it functions and i'm happy to add it to my collection.  first the tang is an obvious replacement.  and i think some parts inside the lock may be.  barrel is 38 inches long stamped JM Caswell Lansingburgh is all i can make out. on bottom of the barrel is stamped  6. locks has JM Caswell stamp also. barrel is tapered octagon and end of barrel mic's .499 trigger guard has saw repair.  hammer works as should but has a lot of travel and feels weak  still snaps a number 11 cap though.  nipple and breech are severely rusted nipple will not budge but have not attacked that problem yet. barrel is clear and pretty clean with bore light.  i love these old guns and would love to hunt small game or shoot round ball with light loads.  i do not have access to the book set Swinney's "New York State Firearms Trade really wish i did guess i will have to buy the set shortly.  can anyone help me date this particular rifle? any info or insight would be GREATLY appreicated!

[adkmountainken]

paid $300

[albert]

The set of Swinneys  books are great  to have.

[adkmountainken]

yes they are at $395.....

[Longknife]

The lock was a flintlock, converted to percussion. If there is a notch cut in the wood behind the hammer then the gun was built as a flintlock. If there is no notch the lock was converted when the gun was built. ...LK