Goofs

When Briggs threatens Marshall with the knife his gloves appear when showing Briggs front and disappear when showing his back.

Shooting training with the hat as a target: the hat ends up with bullet holes in the back but not in the front.

During the ambush of Marshall Jarrett's search party, the Marshall fires his rifle twice in quick succession without loading the second round. The hammer does not fall after the first shot, but does after the second shot.

When Ruth runs to hide in the barn, she drops a crossbar to lock the doors behind her.

The barn doors slid open rather than swung open, making the crossbar useless.

At 1:06, a wide shot reveals a modern paved road cut through the mountain.

Upon reaching the final town of Santa Rosa, the first frontal shot of the outlaws approaching shows a wide modern tire mark in the dirt. Additional tire marks continue to be seen in the town throughout the remainder of the film.

Briggs tells his daughter to take a posse members Rossi, although Rossi shotguns weren't available in the United States until the 1970s.

When Briggs starts shooting at everyone at the start of the film, he shoots a man in a white T-shirt and you can clearly see the fake blood squib that explodes when Briggs shoots him (you can actually hear the pop sound on impact).