FBI Special Agent Richard Messner (Ryan Reynolds) carries the Heckler & Koch USP as his duty sidearm throughout the film, somewhat atypical for federal agents. FBI Special Agent Donald Carruthers (Ray Liotta) and the other FBI Agents also carry the Heckler & Koch USP as their sidearm. The USP is a .45 cal since the .45 auto engraving on the USP's slide is visible when Messner chambers the USP in a car. During the shootout, Messner is seen doing frequent reloads. After Sharice Watters fires her sniper rifle at the FBI, Messner throws his USP at the window after depleting the magazine. He is seen unloading the magazine at the end of the film. In the so-called "Cowboy" ending (seen on the DVD release), Messner uses the USP to do a double tap on two targets.
Beretta 92FS
The Beretta 92FS can be seen in the hands of several of Israel's security team out in the hall as they escort Sir Ivy away and when they get into a fight with the Tremor brothers. Sir Ivy (Common) picks up one of the pistols while in custody and uses it to fire at the Tremor brothers.
Beretta 21 Bobcat
Acosta (Nestor Carbonell) keeps a Beretta 21 Bobcat on an arm sleeve anchor that he uses when his cover was blown. Note the tip up barrel configuration and how the slide ends to accommodate it.
M1911A1
Hollis Elmore (Martin Henderson) borrows an M1911A1 customized with a Caspian Recon slide from an old woman's house after she was taking care of him after being shot and thrown in the lake. He then uses it to shoot and kill Darwin Tremor out of revenge.
Desert Eagle
Jeeves Tremor appears to carry a Desert Eagle when he and his brothers enter a restaurant for a hit.
Glock 17
Several FBI agents including Special Agent Baker (Brian Bloom) carry the Glock 17 as their sidearms. Sir Ivy (Common) takes one off a fallen officer and uses it during a shootout with the Tremor brothers.
Glock 17 (Full Auto)
Lestor Tremor briefly fires his Glock 17 on full auto to take out a security guard who was on fire. Lestor can also be briefly seen firing the full auto pistol up in the air during the Tremor's introduction.
Glock 19
Georgia Sykes (Alicia Keys) carries a Glock 19 as one of her sidearms and uses it when engaging the FBI agents while in the elevator.
SIG-Sauer P226
The SIG-Sauer P226 can be seen in the hands of several of Israel's security team out in the hall as they escort Sir Ivy away and when they get into a fight with the Tremor brothers.
Lazlo Soot (Tommy Flanagan) carries a Sphinx AT 2000 in a two-tone finish and fitted with a suppressor in the last half of the film.
Jericho 941
Georgia Sykes (Alicia Keys) can be seen concealing a Jericho 941 as she prepares to head over to Israel's penthouse.
Revolvers
Smith & Wesson Model 500
Sir Ivy (Common) carries this 4" Barreled Smith & Wesson Model 500 revolver as his sidearm and pulls it on Israel when he finds out he was going to sell him out. Israel throws a card into Ivy's eye then Ivy fires off a cylinder from the revolver through the walls before running empty and being apprehended by Israel's security detail.
Smith & Wesson Model 642
Georgia Sykes (Alicia Keys) can be seen concealing this pistol as she prepares to head up to Israel's penthouse. She then pulls the revolver on Trevor (Chris Pine).
One of Israel's bodyguards, Beanie (Christopher Michael Holley) carries this Smith & Wesson Model 629 Performance Center revolver as his sidearm. Later in the film, Buddy Israel (Jeremy Piven) pulls it from Beanie's holster and nearly commits suicide with it before passing out.
As Acosta prepares to fire his S&W 640 again, Carruthers uses his backup Smith & Wesson Model 340.
Colt Official Police
A Colt Official Police revolver is fired by an FBI agent during a flashback to the 1940s.
Mini Flintlock
Buddy "Aces" Israel (Jeremy Piven) is seen playing around with a mini flintlock pistol when joking around with mobsters.
Rifles
Barrett M82A1
Sharice Watters (Taraji P. Henson) uses the semi-automatic Barrett M82A1 .50 BMG rifle as her weapon of choice. She uses it to shoot between buildings to cover Georgia by taking out several FBI agents. It should be noted that the FBI agents are (unrealistically) sent flying through the air when shot by it.
M4A1 Carbine
One of Israel's thieves (the film's director Joe Carnahan in a cameo) carries the M4A1 during a robbery.
Submachine Guns
Skorpion SA Vz 61
While in disguise, Lazlo Soot (later portrayed by Tommy Flanagan) performs a hit with a pair of custom two-tone Skorpion SA Vz 61s in one of the opening scenes when they were describing Soot's style of assassination. One of these weapons previously appeared in Mystery Men.
One of the police officers is seen with a Remington 870 Police Magnum Riot shotgun when they are ambushed by Watters.
Remington 870 (Police Entry)
Another police officer tries to return fire on Watters with what appears to be a Remington 870 Police Entry shotgun fitted with a tactical light foregrip.