What gun did Doc Holiday use?

Answer 1

This is not really an answer, but more of a speculation. Nobody really seems to know what kind of gun Doc Holliday used. At the time, the Colt .45 Single-Action Army (better known as "SAA") was in wide circulation, and it seems that almost every other person in the Wild West had one. William Bonney, aka "Billy the Kid" had one.

Also, because of his ties and associations to Wyatt Earp-a personal friend of Bat Masterson of Dodge City Marshall fame, who had a preference for the Smith and Wesson Schofield revolver. His was a fancy, chrome-plated affair, similar to what Doc Holliday was claimed to have been seen with.

Also, being a gambler and all-around legendary gunman, Doc Holliday more than likely had more than one gun.

So at the risk of an incomplete or incorrect answer, I would advance the likelihood that Holliday had either a Schofield Revolver, a Colt SAA revolver, or both.