Yancy Derringer lasted just one season, caught in a glut of Westerns. Its Christmas episode, "Old Dixie", is getting some play this month on Get TV (check local listings for forthcoming air dates).
Jock Mahoney was cast as Derringer, posited as a gentleman adventurer, sort of in the mold of Gene Barry's characterization of Bat Masterson, which was running at the same time, except that Derringer had one specific base of operations, based in New Orleans. Federal agent Colton (Kevin Hagen, later of Little House on the Prairie) was Derringer's contact, who often had to arrest Derringer if he broke the law in the course of an investigation.
The problem? This comes across as dull as dishwater. Enough said.
Edit, 2/1/17: Unfortunately, the person who posted "Old Dixie" to YouTube withdrew his account. We will sub the intro: