Factual error: When Wyatt (Kevin Costner) becomes the sheriff/deputy/policeman of Wichita, Kansas, you can plainly see mountains in the background - there aren't any around there. (01:04:47)
Factual error: Throughout the entire film the wrong holsters are used. They are wearing "drop loop" holsters but they weren't invented until the 1930s.
Suggested correction: The claim that "drop loop" holsters weren't invented until the 1930s is incorrect. The style often called the "Mexican Loop" (or Mexican Drop-Loop) holster was already in use by the mid-1870s to early 1880s, especially in the American Southwest and northern Mexico. These rigs were worn over cartridge belts and featured loops that secure the holster to the belt. https://cochiseleather.com/western-gun-leather-history.aspx.
Other mistake: When in the tub in Arkansas, Wyatt is bare chested. In bed with Josie he's suddenly sprouted a lush garden of chest hair. (00:48:06 - 02:02:44)
Suggested correction: Him in bed with Josie is over an hour later in the movie, and in the movie time, years have passed. Him going from a young man to a much older adult. Plenty of time to grow out chest hair or decide to stop shaving his chest. He's a much older man by the time he's with Josie.
Factual error: The movie begins at the end of the Civil War, 1865; it then moves ahead 7 years, to 1872 in Wyoming. Several characters are wearing gun belts with cartridges on the belt. The pistols are Colt Peacemakers probably .45 cal. The problem is that the gun and cartridge were not introduced until 1873 and would take several years to become commonplace. (00:18:31)
Continuity mistake: When Morgan is shot while playing pool he is placed on the pool table. An overhead shot shows a wide pool of blood spreading from his right side. In a subsequent shot the pool of blood is much narrower and a completely different shape. (02:32:44)
Factual error: During a shootout at the end of the movie, one of the gunmen with a rifle is wearing a wristwatch. (02:58:30)
Other mistake: The same Old West town was used for scenes taking place in Wichita and Tombstone. The mountains in the background are those that surround the Santa Fe, New Mexico movie set.
Continuity mistake: When Wyatt meets Doc for the first time, the amount of liquid left in Doc's drink keeps changing. (01:21:32)
Character mistake: In the courtroom scene set in the 1870s, Morgan Earp responds to a defendant with "Nice and easy my ass." While "ass" was used as slang in the 19th century, the dismissive phrase "my ass" as a sarcastic retort isn't documented until much later, making it sound more like 20th-century speech than something cowboys in a frontier courtroom would say, making this an anachronistic turn of phrase. (01:45:30)
Continuity mistake: When Wyatt, his brothers, and Doc are walking to the OK Corral, they are walking side by side. In several shots, they go from walking in the shadows to in direct light, especially Doc Holliday. Also, Doc's right arm keeps going from being up at his chest with his hand in his jacket to down at his side. (02:20:12)
Continuity mistake: After the wagon chase shoot-out where Wyatt tells Dutch to shoot the lead horse, Wyatt is standing on top of the wagon holding his rifle. In one shot, the barrel is up in the air; then in a quick shot of his legs before he jumps down, the gun is pointed down. Then in the next shot, as he's jumping down in a close-up, it's pointed up in the air again. (00:18:56)
Revealing mistake: During the bison shooting scene, a bison goes down close to the camera and both horns jiggle like they're about to fall off. Looks quite fake. (01:00:06)
Continuity mistake: When Doc confronts Ike looking to fight there are a lot of people around. Then from the camera angle from behind Wyatt there is no-one around. (02:01:33)
Continuity mistake: When Wyatt is confronted by Ed Ross in the bar after refereeing the boxing match toward the beginning of the movie, he has a pistol in his belt when throws the cue ball at Ross. Wyatt still has the pistol in his belt when he takes Ross' gun and holster and straps them on. But when he and Sally walk outside right after, the pistol that was in his belt is gone. (00:27:50)
