Most historically accurate film about OK Corral

The OP is basically right that Costner's Wyatt Earp is the most historically accurate recounting of the gunfight at the OK Corral -- as far as we can know. But I agree with poster thbryn, why are we getting bogged down on this subject?

The details of the actual gunfight aren't all that exciting, at least compared to what modern audiences usually expect in such films. So of course the facts suffer in order to make good entertainment. Most of the films about the gunfight have their origins in the books of Stuart N. Lake, who befriended the aged Wyatt Earp in Hollywood not long before Wyatt's death in 1929 and later told the story according to what was essentially dictation from Earp, slanting the facts to put him in the best light.

No movie can possibly tell the full or accurate story because we simply don't know enough. Even Costner's ego project made up a lot. Most people would say My Darling Clementine is one of the greatest westerns ever made, a genuine classic, and it certainly is. But as history it's almost all nonsense -- even the year of the gunfight is wrong.

The OP forgot at least two other "gunfight" films: Frontier Marshal (1939), basically a precursor to My Darling Clementine, and Hour of the Gun (1967), which takes a more innovative approach. It begins with the gunfight -- which is rendered pretty accurately -- and follows its aftermath. Historically, it's a pretty accurate film.

For my money, I like Gunfight at the OK Corral best as an exciting western, closely followed by Clementine. The two 90s films are good but somehow don't resonate with me the way most of the older films do. But these are entertainments, not history. Again, thbryn is right: if you want history, watch the excellent American Experience program on the topic. Complaining that movies that don't purport to be historically accurate aren't is a bit silly.

Anyway, remember the famous line in John Ford's The Man Who Shot Liberty Valance: "This is the West, sir. When the legend becomes fact, print the legend." The many versions of the gunfight at the OK Corral are perhaps the best examples of this maxim in movies.