Factual error: When Buster joins the card game in the saloon, he looks at the hand of the player that had just left. Given the circumstances in the saloon, the cards cannot be spot clean and white as fresh snow. Also, they seem to be plastic cards, which did not exist yet back then.
Factual error: It's winter in Montana, yet there are rattlesnakes out in the cold.
Factual error: All the troops in the Fetterman massacre are cavalry. In fact, the majority of the detachment, including Fetterman himself, were infantry.
Factual error: John Grady Cole's father says that the last time he spoke with Cole's mother was in San Diego in 1942. His lighter has a 3rd Infantry Division badge which means he fought in the European theater of WW2, not the Pacific Theater.
Factual error: Waco Johnny Dean played by Dan Duryea grabs a pistol from a bystander and then gets shot multiple times by Jimmy Stewart. As Waco goes down he fires several rapid fire shots from a double action revolver. Not likely given the time period some time after the civil war.
Factual error: In any number of scenes in this movie characters are seen wearing celluloid badges in support of statehood for Wyoming. This movie is set in the year 1890 and the process of making celluloid badges wasn't developed until 1896.
Factual error: When Brennan rides into town, behind the stage coach in the back street there is a pick up truck parked.
Factual error: The US Cavalry are careful not to run into Confederate cavalry from Fort Davis, who are shown in the distance. Fort Davis was indeed occupied by the Confederates from 1861 to 1862, but was then abandoned until 1867. The film is set in 1864, so there would be no Confederate troops at Fort Davis.
Factual error: In the film, many hostages and policemen are killed and wounded in the final shootout at Glenrowan. In actual fact, two hostages (Martin Cherry and John Jones) were killed and two more wounded, and on the police side only Superintendent Hare, an Aboriginal tracker and a civilian volunteer were wounded. There was no travelling circus present.
Factual error: In a scene set in 1871, several newspaper articles get printed on Moe's face as he falls onto a printing press. Curly Joe reads that "AT&T is splitting two for one." American Telephone and Telegraph Company was founded in 1885.
Factual error: The events in the film take place in mid-1929, as evidenced by the first Academy Awards being presented in May. However, Wyatt Earp went to the happy hunting grounds in January of that year.
Factual error: The highly unstable explosive nitroglycerin plays a crucial role in the film, as it is painstakingly stolen and then used to obliterate a wooden bridge that separates the War Wagon from its armed escort. However, at the end of the film, a single bottle of this incredibly volatile stuff somehow survives to be stolen by an Indian brave who haphazardly snatches it (thinking it is a bottle of whiskey) and scampers away with it. Any one of the Indian's actions, from roughly snatching it to leaping off the wagon with it and impacting the ground, should have detonated the nitroglycerin. The leader of the Indian war party even chugs a mouthful of the Nitro and violently spits it out, the action of which should have exploded his head. But the nitroglycerin doesn't explode until the Indian leader finally throws the bottle to the ground.
Factual error: The events depicted in the movie occur around the time of the California gold rush in 1848, yet every man and his dog wields an 1873 Colt Peacemaker.
Factual error: When Tom is singing "If You're Ever Down In Texas" to the cowgirl, Jerry winds the crank on the Victrola counter clockwise.
Factual error: Raquel Welch is shown to have modern tooth fillings during the rape scene.
Factual error: This movie takes place post-civil war, and Fisher, in his first discussion with General Cortinas refers to the "Republic of Texas" being ripe for the taking. Texas ceased to be a republic in 1845, when it joined the United States.
Factual error: Engine 463's firebox is seen in a close-up, revealing a cast in date mark of 1914. The caption near the start says it's set in 1892. (02:02:00)
Factual error: On their journey, Rooster is bragging about his navy colts, when actually his sidearm is a Colt .45 Peacemaker, also known as an Army Colt M1873.
Factual error: Purdy is always wearing a bra with hook and eye in the back. These bras were not patented until 1911, much later than when the movie is depicted. (01:12:20)
Factual error: When Pauline is burying her husband in the cemetery there is a shot of a mountain with vultures swarming around it and an antenna mast is visible on top of the mountain. (00:24:18)