Factual error: The movie is set in 1882, however there is a scene where he meets Doc Brown with his DeLorean. Back to the Future Part III took place in 1885.
Factual error: The newly born foal is too dry and too steady on its legs. (00:22:25)
Factual error: In the scene where Lee Marvin states that Burt Lancaster loves explosions, Burt Lancaster makes a remark about the big bang theory. He says: the whole universe started with a big explosion. The film is set in 1917 which is 10 years before Georges Lemaître launched the big bang theory.
Factual error: Throughout the movie, characters strike matches to light lamps. While "strike anywhere" matches had been invented by this time and were quite the rage in Europe (despite an alarming tendency to explode due to the volatile chemicals used), they were an unknown commodity on the American frontier until well after the turn of the century. (00:49:00)
Factual error: It seems unlikely that the bullet hole in Harmonica's jacket should have burned edges - he was shot at a distance of more than ten metres. (00:36:35)
Factual error: The chairlift for the ski resort on Mount Hood is visible in the scene that pans to the right just before James Stewart is abandoned on the mountain. This ski resort was not around when the film is set.
Factual error: In the scene where the people of Rejection/Perfection are preparing to fight the Dirt Dragons, Hereim loads the Punt Gun and puts a little gold piece in it (a percussion cap, containing a small amount of gunpowder used to set off the main charge in the barrel). He shoots at the Dragon when it pops up and misses. The next time he loads the gun, he does not replace the percussion cap (which can only be used once), yet he is still able to fire the gun with no problem and kill the Dirt Dragon.
Factual error: Upon completing the task of lowering every wagon, horse, mule, ox and human down to the canyon floor, the settlers proceed to build rafts for their wagons..however, their scout would have informed them that they would be going overland to intercept the Columbia River to the northwest. The Snake River, with class IV rapids, (even now tamed with dams) was no place for the uninitiated to go rafting.
Factual error: When the lone ranger fires his guns at the train he shoots over 20 times, despite using a 6 shooter. Likewise when Fuller is shooting at Tonto through the roof. (02:06:55 - 02:07:30)
Factual error: In one scene where Travis walks out the door of the kitchen half of the cabin, there is a thermometer nailed beside the door. In the late 1860's, when the movie takes place, thermometers like that were not available.
Factual error: The girls stop at a grave site, and the marker indicates the husband had died 3 years earlier, in 1888. Yet, later on, Cody tells Frank that they're going to the "Oregon Territory". Oregon had been a state for over 30 years by that time.
Factual error: In the beginning of the movie there is a shot of the flag being raised over Fort Stark and the sound of a bugle is playing. The bugler is playing "Retreat" which is only played when the flag is coming down; he should be playing "To The Colors".
Factual error: During the battle scene the voiceover says that it is February 1915. The battle being portrayed is obviously the Second Battle of Ypres because it involves Canadian troops and it's the first time that gas was used in the war. The actual battle didn't take place until the end of April 1915.
Factual error: The scene where Jon Wayne's Son is shooting the deer at 600 yards, he swings his rifle about 20-25 inches in about 2 seconds - by my calculations the deer must have been travelling around 250 mph.
Factual error: The bed in the "Haberdashery" has a box spring under the mattress. Referring to a "History of Bedding": "By 1927...box springs with ticking covers were still new." Having one in this time and remote location would have been impossible.
Factual error: The film takes place in Kansas, reprising the original "High Noon", yet during the chase, both the pursuers and pursued wend their way through Saguaro cacti, only found in Arizona.
Factual error: The movie takes place in the early 20th century (1910s or 1920s or so). When Dean and Jerry are riding in a RR cattle car with its doors open you can clearly see parked automobiles from the 1950s through the open door of the train car.
Factual error: When Bloomington offers the reward for Cherokee Kid's carcass, the undertaker asks a man if he's right handed or southpaw. The term southpaw originates from baseball stadiums from the 1920's. Home plate usually faced east to keep afternoon sun out of the batter's eyes, this makes the pitcher's left hand be to the south.
Factual error: In the final gunfight, we see a close-up of Charley fanning the hammer and rapid-firing his six shot Colt Single Action Army nine times in a row. [Kostner has stated in interviews that this occurs because a short scene of him switching revolvers (he had a second revolver in his belt) was left on the cutting room floor. Still a mistake, but there's the reason.]
Factual error: The action in this movie takes place in 1869, yet half of the handguns are 1873 Colt Peacemakers, and the remainder that are Army or Navy Colts are all cartridge conversions, which were not available until 1871.