Brill (Gene Hackman) carries an original U.S. Army Colt M1911 .45 ACP, which he holds on Robert Dean (Will Smith) at a hotel in order to ensure Dean is not a federal agent pursuing him. Apparently he doesn't regard him as a real threat, since the gun isn't cocked and can't be fired.
Glock 17
Robert Dean (Will Smith) takes a 2nd Generation Glock 17 from a police officer, which he fires several times while being pursued by Reynolds' men in a tunnel. He later gives it to his wife for her own defense, and it is not seen again afterwards.
Remington 870 sawed-off
Brill keeps a sawed-off Remington 870 shotgun in his El Camino, which he gives to Dean to use against the NSA agents while they are being pursued. Brill later uses the shotgun to intimidate the driver of a Mercedes that he and Dean carjack.
SIG-Sauer P226
Nearly all of the NSA operatives who pursue Robert Dean carry 9mm SIG-Sauer P226 pistols. NSA Assistant Director Reynolds (Jon Voight) wields a P226 at the climax of the film, which he uses to shoot Brill in the hand.
Beretta 92FS
The two ex-military cutouts Krug (Jake Busey) and Jones (Scott Caan) carry the Beretta 92FS instead of the SIG P226s that are favored by the NSA operatives.
Savage/Stevens Model 311 sawed-off double-barrel shotgun
A chef in Pintero's restaurant kills Krug with a Savage/Stevens Model 311 sawed-off double-barrel shotgun. He later uses it to threaten Dean before being captured by FBI agents.
Taurus PT92
One of Pintero's men uses a Taurus PT92 at the end of the film.
Vz 61 Skorpion SA
Another of Pintero's men is seen using a Vz 61 Skorpion SA during the final shootout.
Smith & Wesson 5904
One of Pintero's men uses a Smith & Wesson 5904 pistol in the final shootout.