Several options. A Spencer carbine wins lots of style points....or, you could be mustered out of service & come back as a scout?...or, how about promotion to an officer (involving a hefty pay raise). Officers had the option of using private purchase firearms...at least in the 7th cavalry - should be a good starting point for documentation.
The field piece of artilleryman would be cool, but hard on targets and backstops
![Grin ;D](https://www.cascity.com/forumhall/Smileys/cowboys/grin.gif)
Regards,
Slim