Factual error: In one of the opening scenes of the riders heading toward the town you can see contrails of aircraft on the lower left horizon.
Continuity mistake: While Bogue shots the guy outside the church the sun changes between shots.
Continuity mistake: Towards the end of the movie when Bogue's men are first charging into Rose Creek, we see white tents camped on the outskirts of town in the field. The next wide shot from a distance there are no white tents, then the next shot there are. In the final scenes of the movie as the camera pans over the town and into the field, there are no white tents visible.
Revealing mistake: In the Gatling Gun scene when the camera cuts to a short couple frame shot showing a closeup on the .45-70 Government ammunition casings on the ground that are falling from the gun, the casings are star crimped. Star crimped casings indicate blank ammunition. Standard ammunition isn't possible with star crimping. The size and casing shape indicates .45-70 Gov which was popular in these guns at this time. (01:46:40)