Cosmatos was highly focused on accurate historical detail, including the costumes, props, customs, and scenery, to give them authenticity. All the mustaches in the movie were real. Val Kilmer practiced for a long time on his quick-draw speed, and gave his character a Southern Aristocrat accent. Two locations were used to make the town of Tombstone look bigger. The scene in which Wyatt throws an abusive card dealer (Billy Bob Thornton) out of a saloon was to show that Wyatt was a man who used psychology to intimidate. Thornton's lines in the scene were ad-libbed, as he was only told to "be a bully".