During one of the fight scenes, Dave is seen bending slightly with his gun pulled from its holster. There is a quick cut, and then back to Dave where he reaches to pull his gun from its holster when it had already been removed.
At the end of the movie, the cart loaded with guns is standing close to the edge of a hill. Will Lockhart and Vic Hansbro push it forward, but in the next shot from the bottom of the hill, the cart is in the same place.
When Vic brings Dave's body back to the ranch, there's a lighted lamp on the porch behind Alec, even though it's obviously daytime. Then, when Alec leads away the horse with Dave's body, the lamp is out.
(Around 25:30): After the fight, Alec turns back, and Vic strides over the fence (to Will's right). A few seconds later, Vic strides over the fence again.
When Will Lockhart and Barbara Waggoman walk together in town, Will Lockhart stops close to a pole, but doesn't lean against it. However, he is seen leaning against the pole in the next shot.
Two of Dave's men are holding Lockhart as Dave prepares to shoot Lockhart's hand. One of the two men is in the direct line of fire, and since Dave is shooting Lockhart's hand at point blank range, the bullet would have gone through his hand and struck Dave's henchman.
At the end when Lockhart is ready to leave, he tells Barbara that if she goes east she will pass "through Laramie". If she went from New Mexico to Laramie, she would have to go almost due north, not east.
However, as stated elsewhere on this page, at that time "east" was less a direction and more a location: specifically, New England. Even if that were not the case, his was a hopeful suggestion that she pass through Laramie regardless of how she gets there.
It is unexplained how Lockhart managed to escape from the Indians at the end. But it doesn't have to be explained, the Indians have no reason to be looking for him; they don't know he exists. All their business was with Vic and/or Dave.
When Lockhart catches up to Hansbro at the wagon full of rifles, Lockhart says that he had traveled a thousand miles to kill Hansbro. But Laramie is no more than 750 miles from any spot in New Mexico. However, he never said he rode in a straight line to get to Coronado. If he'd had to go around rivers, valleys, Indian lands, or whatever, the trip would easily cover a thousand miles or more.
During the fight scene about 1/2 hour into the movie, just before Jimmy Stewart pushes Alex Nicol into the water trough, you can see that Stewart's pants are split down the middle. They are fine shortly later.
When the doctor is checking on Alec, according to the clock it is first 9:30 and then after a scene change, 11:30. Since Lockhart found Alec during the daytime, it must have been evening when the doctor checked on him, but it was as bright as if it were high noon even at 11:30 in the evening.
While Alec's eye sight is growing worse he's still able to read without the aid of reading glasses or a magnifying glass.
Lockhart tells Barbara that when she goes east she'll go through Laramie. It was typical to refer to New England as "East", in other words as a location, not a direction, so when she decided to go to the east coast she could stop in Laramie. Up until 1870, the easiest way for her to go east would have been by rail and the nearest place to catch the train would have been Cheyenne, 55 miles east of Laramie. But after August of 1870, the Kansas Pacific Railroad provided service from the East to Denver making it the logical connection point and only half way to Laramie.
One of the film's key points is that Alec Waggoman, the cattle baron, is losing his eyesight and has a great deal of difficulty seeing at distance. Yet he is clearly able to ride a horse and later is able to recognize one of his men who is in a dusty cattle pen and fighting the protagonist at a distance.
When the doctor emerges from Alec's room, he is asked "How is he, Doc?...". The doctor replies, "He's still unconscious" and a few moments later states, "he's totally blind". If the patient is still unconscious, the doctor would have no idea as to the visual acuity of the patient.
Just after Lockhart battles the guy trying to knife him in town, the store Indian runs up a ladder. The ladder clunks and is metal, not pine poles as it should be.
Many of the clothes worn by the cowboys are not period authentic. This includes the hats worn by the men, their shirts and especially Jimmy Stewart's jean jacket which is clearly a model from the early 20th century.
The haircuts worn by the men are those of the 1950s filming era rather than the 1870s setting.
When Barbara Waggoman first meets Will Lockhart, and again later on, she is clearly wearing a modern brassiere under her dress and blouse. Bras weren't invented until decades later.
The deer head hanging in the Waggoman Mercantile is a whitetail deer, found in the eastern U.S. Not a mule deer common to the west.
Merely pushing a wagon load of rifles off the cliff would not make all of the weapons useless. Even the ammunition exploding at the bottom would not cause major damage. The Indians would still be able to make use of many, if not most of, the guns.
It makes no logical sense that Vic did not allow the ranch hands to kill Will Lockhart, as this would have allowed Will to be blamed for Dave's killing.
The Indians would have also killed Will Lockhart, not just Vic Hansboro.
There is no reason why Vic would have remained on the ranch, as Alec had made clear he would not inherit anything.
Barbara asks Will about Daniel Boone's travels. Daniel Boone never came close to the Rockies as Barbara asserted.