There's two, actually, tied for "Best."
The "Best" historically accurate western of all time is Unforgiven.
Nothing else comes close. Everything from the weapons used to
how gun fights took place were pretty accurate, and certainly
more accurate than any other portrayal in American film. Even the
pacing was realistic! They nailed EVERYTHING.
The cast was top-notch, the characters were deep & flawed...
The "Best" western in the finest Hollywood tradition has to be
Honestly, Val Kilmer ROCKED IT as Doc Holiday. He was a supporting
character yet you could rename it "The Doc Holiday" story he was so
Kurt Russel? Sam Eliot? Bill Paxton? Unreal.
This was a good old fashioned Hollywood western EVOLVED!
Such a good film... such an awesome film.
Comparisons of the two films are interesting. Take the aforementioned
"Flaws" within the Unforgiven characters, and look at them side by
side with the traditional White Hat/Black Hat portrayal in Tombstone.
Or how everyone (except the prostitutes) in Unforgiven seem to be
well anchored in their homes, even Clint Eastwood's character isn't doing
too good. In Tombstone everything is centered on saloons & fast draws,
just like the westerns of Hollywood's golden age...
Yes, one is Hollywood evolved -- refined & raised to its finest expression --
while the other is perhaps the most realistic western that will ever be
produced while still being good.