According to the movie's script doctor William Goldman, Clint Eastwood, Robert Redford, and Harrison Ford passed on the movie. These men would have fit the literary Bob Lee Swagger's age a bit more closely than Mark Wahlberg (born in 1971). Author Stephen Hunter introduced Swagger as a Vietnam veteran in a 1993 novel, taking place in 1992. However, to accommodate Wahlberg's age, this film has Swagger active in Africa in the 1990s, instead of Vietnam in the 1970s.
The website to which Nick Memphis (Michael Peña) is given a link in the chat room, precisionremotes.com, is real. It is the website of Precision Remotes, a Richmond, California company, which designs and manufactures remote-operated weapon and surveillance platforms, such as the one featured in the film.
Stephen Hunter named Bob Lee Swagger after his longtime friend and colleague, Baltimore Sun photojournalist Weyman Dexter Swagger (1943 - 2010). The two worked together at the Sun for over a decade, and it was Swagger who introduced Hunter to shooting and gun culture.
The large caliber rifle that Swagger owns, with which he is framed, is a Cheyenne Tactical M200 Intervention. It fires a .408 caliber projectile accurately out to and beyond two thousand meters. The CheyTac M200 is also available with a Long Range Rifle System, which consists of a laser range finder, magnifying scope with night vision capability, and a weather-sensing module, all of which interface with a PDA running ballistics calculation software.
During the mountain top confrontation, Swagger kills one of the snipers by shooting the counter-sniper through his rifle scope. This is likely based upon an infamous kill by renowned U.S. Marine Corps Gunnery Sergeant Carlos Hathcock during the Vietnam War.
Swagger sees the last sniper when the sun glints off his binoculars. Carlos Hathcock spotted the sniper sent to kill him when the sun glinted off his scope. Hathcock shot at the glint. His bullet went through the scope and hit the sniper in the eye, which means that Hathcock, like Swagger, was in the other sniper's sights. They shot quicker and lived.
The dog featured in the film as Bob Lee Swagger's companion was trained by owner Drew Thompson. The dog's real name is Logan. He is a Bernese Mountain and English Mastiff X. Drew states that "he is easily the smartest dog I have ever trained".
Athens, Tennessee, the residence of the firearms expert Swagger and Nick visited, was the location of the "Battle of Athens", where in 1946, armed citizens removed the corrupt local government, and restored free elections.
Throughout the film Swagger does change which eye he uses to scope his targets. This is mentioned by a previous poster as cause for him to miss some of his shots. There are two reasons why Swagger could still make all his shots, even with switching which eye he sights with. One possible reason is that there is a small percentage of the population who are not eye dominant. This is uncommon, but is the case in some instances and means they can shoot equally well with both eyes. The most likely reason in Swagger's case is that even if he is eye dominant, you can learn to shoot with both eyes. Being he is a HIGHLY skilled sniper with extensive training, he probably did learn to shoot with both eyes.
The author, Stephen Hunter, was close friends with Dexter Swagger, whom he worked with at The Baltimore Sun. He thought the name was perfect for his character. He stated this in the eulogy at Dexter Swagger's funeral.
This film is the third in which Wahlberg has portrayed a character with a name that's a variation of Robert. The first is The Perfect Storm (2000), in which he portrayed Bobby Shatford, and the third being Four Brothers (2005), in which he portrayed Bobby Mercer.
Actor Ned Beatty as Senator Meachum gave his reality speech about no Suni no Shites and only so many seats at the table to Bob Lee Swagger played by Wahlberg. Beatty also gave a similar reality speech about no religions and no Arabs in the 1976 film "Network" to actor Peter Finch as newscaster Howard Beale.
At around 17:15, Swagger (Mark Wahlberg) directs his M200 at a can of beef stew he set up for target practice. He locks his scope dead center on it and looks over at his dog and says "1760 (meters), that's about a mile". At that distance, a shooter has to take into account wind, bullet spin drift, the Coriolis Effect, etc. which means Swagger would have needed to apply "Kentucky Windage" to compensate for these variables. In other words, the scope would have been off center as snipers use the scope cross hair mil dots to compensate. In addition, the Cheytac M200 Intervention sniper rifle includes a ballistic computer PDA as well as mathematical documentation to aide in precise aiming which means the scope would be anything but dead center on the beef stew can.
The trivia items below may give away important plot points.
The ranch shoot-out scene was scaled back due to the violence. The scene in which Bob Lee Swagger (Mark Wahlberg) kills a bodyguard with a knife to the throat was scaled back tremendously. Originally, the knife was supposed to exit through his nose, causing blood to spray on Swagger. The scene was cut because the MPAA deemed the scene too brutal.