Ref: Combat Handguns, M. Ayoob
No less a legendary Lawman than Wyatt Earp experienced a dropped-gun accidental discharge. In what is probably the most detailed biography of Earp, Wyatt Earp: A Biography of the legend, veteran historian and ackowledged gun expert Lee Silva researched a news clipping from the time, that he quoted Volume 1: The Cowtown Years.
Silva found it in the January 12, 1876 edition of the Wichita Beacon. It read
"Last Sunday night, while policeman Earp was sitting with two or three others in the back room of the Custom House Saloon, his revolver slipped from his holster and falling to the floor, the hammer which was resting on the cap, is supposed to have struck the chair, causing a discharge of one of the barrels(sic). The ball passed through his coat, struck the north wall then glanced off and passed out through the ceiling. It was a narrow escape and the occurrance got up a lively stampede from the room. One of the demoralized was under the impression that someone had fired through the window from the outside."
Silva also gained access to some of Earp's correspondance with his compliant biographer, Stuart Lake, in the late 1920's. He had apparently admitted that it happened when Lake asked him about it, and in a note asked Lake to leave out "the little affray with the chair." Lake complied.
And when Lake's Wyatt Earp, Frontier Marshal did come out a few years later, Earp was emphatically quoted in it as saying professionals would never carry a live round under the hammer of a single-action revolver.
For what it's worth................