Factual error: In the opening sequence, the range for the shot is confirmed as 650 yards. Moments before the shot, AFTER he had his target centered in his scope, Berenger swings the muzzle of the rifle at least 10 degrees. At 650 yards a change of only a single degree in the angle of the muzzle to the target would mean that the target would have to move 11.34 yards laterally in order for the shot to hit. If Berenger actually had to swing his rifle ten degrees in the span of a second in order to keep his target in view, that would mean the target was sprinting at a speed of 340.32 feet per second, or about 232 miles per hour, and had covered 113.44 yards during that time. Absolutely impossible.
Factual error: When in the helicopter the red dot from Miller's sights stays motionless on the EXACT same spot on the man's back - impossible from a helicopter. Doubly so if compared to the scene at the lake, where Miller is sitting totally still and the red dot is moving back and forth over the swimming guy's head.
Factual error: The only railroad in Panama is runing North-South right along the Panama Canal. Not very usable to get "deep into the jungle" - and there are no mountains.
Factual error: When Berenger and Zane are resting, Berenger brings up the "best steelhead fishing" in the state of Montana. Since a steelhead has to migrate to the sea and return to be a steelhead, there is no ocean access to rivers in Montana.
Answer: According to an old post on the Bladeforums website, it was an 8" Al Mar Shadow.