The Earp Buntline Special was very likely a myth perpetrated by Stuart lake, and also as likely abetted by Wyatt himself by telling Lake what he obviously wanted to hear. No documentation exists of Earp ever carrying a Buntline during the execution of his duties in Tombstone or anywhere else, and there isn't really a clear record of his ever having owned one, though he probably did.
Why would he tote a sixgun that would be hard to manage in both carrying and in quick presentation in a time when men could lose their lives in fractions of seconds? I imagine that a 10 or 12-inch revolver would be a real drag to carry.
Here's an excerpt from William Shillenberg's article:
"The Myth of Wyatt Earp's Buntline Special."
lthough Wyatt supposedly told Stuart Lake, "Mine was my favorite over any other gun." If the Buntlines "caused a lot of talk in Dodge" it certainly didn't impress Wyatt Earp enough to note the incident. John Flood admitted being confused after reading Lake's Buntline Special story in The Saturday Evening Post. Flood later remarked to John Gilchriese that he and Mr. Earp discussed weapons in detail many times but no mention was ever made of such a gun. [82] Also, the late Raymond Thorp told a story about Wyatt Earp showing him a revolver in the late fall of 1914. At that time, he said, Wyatt carried a Colt S.A.A. with a 5-1/2-inch barrel. Thorp claimed Earp told him, "I don't like a gun with a longer barrel. Sometimes an inch or two makes a difference when you want to jerk it quickly."