Continuity mistake: When Jesse and Frank are telling the doctor that his son was killed (right in the beginning of the movie) Jesse gained a lot of beard growth in five minutes. When they are outside talking to Zee, he has just a light beard, and then when they go inside he has a heavier one.
Continuity mistake: Just after Samuel and Alfred say that they are going to enlist, Samuel has a weird looking face and notice Alfreds shoulder right behind him, then Susanna takes a few steps up the stairs very sad and Samuel walks a couple of meters towards her and then she leaves and then it switches to Samuel with the same funny looking face and Alfred is again right behind him. (00:24:20)
Continuity mistake: After Evans was shot near the end of the movie, Ben Wade jumped out of the train to look at him. If you look over Wade's shoulder, you will see that Nez (the Apache) had already arrived at his spot, and Campos (the Mexican sharpshooter) threw Wade's gun belt to Charlie Prince. After the movie cut a couple of times, Nez was shown walking up, throwing Wade's gun belt to Campos, who then threw it to Charlie Prince.
Factual error: We learn that the previous sheriff, Charlie Wade, took revenge on anyone who smuggled illegal immigrants across the border in the late 1950s - we are shown the smuggling, as Eladio Cruz hides a group of Mexican men in a watermelon truck to take them across the border. However, in the 1950s, the border was not fortified the way it is now - the smuggling shown would simply not have been necessary.
Revealing mistake: During the Little Bighorn massacre one of Custer's lieutenants turns to address Custer and is struck in the back with an arrow, and the thick pad or board is visible under the actor's shirt.
Continuity mistake: In the scene where they ride to the top of a hill on horseback, you can see a white van and power lines in the distance.
Factual error: Throughout the film Doc Shabbit is carrying a rifle that is supposed to be a Henry repeater. If you look closely it is a Model 1892 Winchester with the forearm removed and a piece of metal welded on the magazine tube to simulate the magazine plunger. The plunger is up against the front of the receiver, which indicates the magazine is empty. Most weapons carried by other characters are pretty much period correct, but a main character has a cobbled up weapon.
Continuity mistake: When Francis Fryer throws the cowboy he loses the scarf in his hand but when the camera angle changes he has it again.
Continuity mistake: During the desert chase sequence, when our hero is run off the road by Ernest B. his missing arm is momentarily transposed when he steps from the jeep.
Continuity mistake: When Luz is talking to Jet on the phone for the first time, from the front she's fiddling with the phone cord with her left hand. When it cuts to the reverse, however, her hand is flat on the desk.
Factual error: After they bury Jack's father, the stage driver hands Jack what he refers to as a "Navy" Colt. However, in 1841, the only colt handguns were a handful of Paterson revolvers, usually carried by Texas Rangers, and in fact, the revolver handed to the boy was a cartridge weapon.