Colt Revolving Carbine Model 1855 - Revolving carbine, percussion. AF*74613M.
The <a href="https://en.wikipedia.org/wiki/Smithsonian_Institution" class="extiw" title="w:Smithsonian Institution">Smithsonian Institution</a>
<a rel="nofollow" class="external free" href="https://americanhistory.si.edu/collections/search/object/nmah_416376">https://americanhistory.si.edu/collections/search/object/nmah_416376</a>