Warfield jumps from standing to being mounted on his horse between shots.
During the fight with the Apaches in the Mormon ghost town, Forbes shoots out of a window with his pistol right next to his face. In actuality, the recoil of the weapon would have carried it right back into his nose like a punch. In the same scene, Captain Addis shoots a shotgun from a window in a similar fashion, a weapon with even more recoil that, in reality, would have slammed into his face and probably given him a black eye.
The Apaches are shown running along the ridge line when coming to attack the town. They are very clearly visible and common sense dictates that you don't skyline yourself for others to see.
After the fight in the Chinese restaurant, Lorn Warfield (Glenn Ford) leaves the restaurant and begins walking down the street, where he pulls one of the townsfolk aside and mentions the price of selling someone out. In the background of this scene, behind the actors, the front nose and fascia of a 1960s-era black pickup truck can be seen parked between a wagon and the side of a building.
Throughout the movie, Glenn Ford has his pistol taken away several times when captured by Apaches or army deserters. Near the end of the movie, the evil gun Glenn trades to the storekeeper is obviously not his original pistol: the handle and grip are different.