Continuity mistake: During the opening sequence of the film, Bob fires at the helicopter with his M82, and the helicopter is seen doing a strafing run over Bob, and both of the mounted 50 cal machine guns disappear from the helicopter.
Continuity mistake: In the beginning where Bob and Donnie are watching over the road waiting for the returning troops, the bolt of the M40 rifle Bob has at the ready is closed. In the shot right after Donnie pulls out the picture of Sara, the bolt is shown open, but appears not to be fully open. In the next shot of the rifle, the bolt is again closed. We do not hear the bolt, nor would a sniper at the ready fumble with an arm at the ready.
Continuity mistake: In the very beginning of the film when Swagger takes out the enemy's truck approaching friendly troops, the truck flips over onto its side and two pieces of the truck spill out onto the road, yet when the friendly troops approach/pass it the objects are nowhere to be seen.
Continuity mistake: Close to the end the movie, when the helicopter Danny Glover is in is approaching, we see a reflection in its high gloss paint: mountains, snow, rocks. When it lands, the paint is matte blue, no reflection. We would have seen the camera crew easily if it had still been glossy.
Visible crew/equipment: About half way through the film when they go to see the old gun smith, as they get out of the truck and just after Swagger says "welcome to Tennessee, the patron state of shooting stuff" and closes the truck door, you can see a reflection of someone holding a board or something in the wing mirror.
Continuity mistake: When Swagger kills the senator, he uses the last bullet in the clip, this is seen by the gun slide being left back. If there had been more bullets it would have reloaded and gone back to the original position. However a millisecond later, in the next clip the gun has been reloaded.
Factual error: When the Ethiopian Archbishop is killed you hear the gun go off and the Archbishop dies almost immediately, but as Swagger also points out, the hang time would actually be around 5 to 6 seconds (and it would take the sound up to 11 seconds to travel that far). Which means that, when we see it from the gun's point of view, there should be quite a long wait for him to get hit.
Factual error: Bob and Nick engage in a shootout in Lynchburg Virgina in the late afternoon (according to FBI Howard), then call him from Bozeman, Montana, the very next morning, standing in front of the very same Dodge pickup. Even allowing for the passage of 18 hours, they would have had to average over 119 mph, not allowing for fuel stops, to get there.
Factual error: In the scene with the helicopters landing on the mountain top there should have been snow blown up around them as they land from the force of the blades.
Continuity mistake: Approximately 3 minutes into the film, the scene cuts from Bobby Lee Swagger and his scouter to the U.S. Camp in Ethiopia, you can see a truck pulling into the camp, if you watch closely from the beginning of this scene to the following overhead shot, there are a few changes, the U.S. flag on top of the camouflaged tent disappears, there are twice as many red barrels at the entrance to the camp than in the previous shot.
Continuity mistake: In the beginning of the film when Swagger and Donnie begin fighting insurgents, Donnie spots an enemy officer in a yellow jacket with a radio behind a red truck and Swagger shoots him down. Shortly afterwards we see this same commander alive, exiting the red truck and taking cover.
Factual error: Right after the 'trap' for Swagger, two soldiers enter the house with Swagger waiting for them on the inside. Swagger shoots the first one twice, but after wrestling with the 2nd one for a bit, Swagger shoots through the safety helmet to kill the 2nd soldier. This would be impossible since these helmets are made to withstand much tougher weapons that a 9mm Beretta. What's even worse is that the blood comes out on the other side, meaning that the bullet pierced the helmet twice.
Revealing mistake: When Swagger is on the mountain and looking though his scope at the guy with the shotgun, the audience is shown what Swagger sees though his scope. However, the pictures we see does not match that very telescopic view Swagger would see at that distance but instead something shot with a relatively wide angle lens at close distance.
Factual error: When FBI agent Memphis is reviewing the assassination on video, you can hear the shot first and then see the blood spray of the bullet impact on the Archbishop. This defies physics as bullets travel faster than the speed of sound. Given the distance the sniper shot from, the sound of the shot would be be heard a second or 2 after the impact.