(at around 34 mins) In the hunting scene the number of arrows in Emil Kovac's quiver is not consistent with his shooting.
At the beginning of the film, when US soldier is opening railway car he is wearing gas mask. In the next shot soldier no longer has mask and covers his face with his hand.
When Ben is holding Emil at gunpoint on the rock, his hands alternate between holding the rifle above his waist and below in between shots.
There were no US ground forces involved in this conflict besides US Marines who rescued a downed US pilot (Scott O'Grady). Nothing like the mission depicted at the start of the film, which is the premise of the whole movie, took place.
The rifle on cabin wall is a Winchester 1873. In later scenes, the rifle used is a Winchester 1892. The rifle thrown over the cliff is a Winchester 1873.
Near the beginning of the film when Ben is processing the photos, he erroneously hangs them after the first tray which contains developer. Photos should be hung only after the water rinse or later.
In the final scene, as Ben exits and taxi and climbs the stairs to his son's front door, he is limping significantly on his left leg although it's his right leg that was injured.
When talking on the radio shortly after Ben makes a new bow, Emil says to him "looks like you missed your little nephew's baptism." It was his grandson's.
Shortly following a screen that says "In 1995..." a soldier is shown with an EOTech holographic sight on his rifle, which would not have been available until 2001 or so.