Character mistake: On the day Rebecca arrives home, Junior Douglas says that he was "Valedictorian, Class of '95." Earlier, Drago talked of almost killing Running Buffalo "during that trouble back in the '40's," which would have been about 50 years earlier. That would mean Drago and McLintock were fighting Indians when they were babies, or possibly before they were born!
Character mistake: When Wes is drinking the mezcal with the worm in it, he makes a toast to "la vida luna" and tells Sissy it's Spanish for "the crazy life". This is untrue, the correct Spanish translation for "the crazy life" is "la vida loca". "La vida luna" literally translates as "the life moon" or better yet "the moon life", but a more accurate translation is "the night life."
Character mistake: In a conference with Crockett and Bowie, Travis states that Fannin in Goliad is preparing to relieve the Alamo and will be ready to "march south by the end of the week." Goliad is 90 miles south of San Antonio. To relieve the Alamo, Fannin would need to march north.
Character mistake: In the scene where Quigley engages Marsten's men who are attacking the Aborigines, we see a man hit by a bullet and fall from his horse, then we hear the report of Quigley's rifle. When the man who gets away reports to Marsten, he estimates the range at three-quarters of a mile maybe. Marsten asks him how long after the bullet struck before he heard the report of the rifle. He answers two maybe three seconds. While this scenario would be plausible for a more modern high-powered cartridge like the .30-06, it is not accurate for the .45 2-7/8 Sharps Quigley is using. That cartridge loaded with 110 grains of black powder will propel a 540-grain bullet (best case) at around 1475 feet per second. Since the bullet is supersonic when it leaves the muzzle it will indeed precede the sound of the weapon's discharge for short distance. But not by very much and not for very long. The bullet goes transonic in about 400 yards and the the sound waves catch up to the bullet a little beyond 600 yards. After that, the rifle's report, travelling at a constant speed, gets progressively further AHEAD of the bullet which is gradually slowing. At three-quarters of a mile (1320 yards) the bullet's time of flight is about four seconds, while sound waves travel that same distance in three-and-a-half seconds. The man should have been struck at nearly the same time as, or up to half-second AFTER the report, depending on the actual range.
Character mistake: The check written by Sam Jackson says May 2, 1858. At this point in the movie, it should be 1859.
Character mistake: Stoddard in class says the founding document of the country can be added to with amendments. Pompey says it is the constitution written by Thomas Jefferson. Stoddard says 'declaration of independence'. Pompey was right, Stoddard incorrectly corrected him. It IS the constitution. The declaration can't be added to with amendments.
Character mistake: When Buster gets hit in the arm the first time, he is busy tying the kerchief below the wound. (02:21:05)
Character mistake: When Eastwood is trying to mount the horse for the first time he is pulling on the inside rein, which makes the horse turn away from him. Even a child of that time would know to pull on the outside rein to make the horse turn into you.
Character mistake: Mattie attended a travelling Old West show in Memphis in which Rooster Cogburn was a performer. The flyer for the show shows the date of the show as July 18, 1903. The day of the show Mattie was told that Rooster died three days earlier (July 15, 1903). But Rooster's tombstone lists the date of his death as August 12, 1903. (01:41:55 - 01:43:35)
Character mistake: The bartender in El Dorado was John Mitchum - Robert Mitchum's real life brother. "Elmer" was the character name of the bartender, as mentioned twice in the first saloon shootout mid-way through the movie and in the movie credits under "Elmer, Jason's Bartender." Robert Mitchum mistakenly calls to the bartender, "freeze it right there, Johnny" (inadvertently using his brother's real name, "John, " as opposed to his character's name, "Elmer") in the final saloon shootout scene. (01:20:59 - 02:00:22)
Character mistake: At the confederate prison camp after they are captured a soldier comes up to the sergeant (Van Cleef) and informs him that the "Captain" wants to see him right away. In the next shot with Van Cleef where he is talking to the commanding officer you will see that he is not a captain but a major.
Character mistake: After Maverick gives the "actors" their hundred dollars, he says "News travels fast in the Old West." Why would he refer to the west as "old" when, for him, it's the present? This is an expression that didn't come about till later on, when the west BECAME old.