Charly Baltimore uses a Nickel SIG P226 pistol - 9mm. She is shown holding a K-Kote (black) SIG-Sauer P226 on the movie poster but she doesn't use one in the film.
Ruger KP94
Timothy (Craig Bierko) has a Ruger KP94 in his waist band, which he uses later to try to kill Mitch Hennessy, when he gives him the option of being killed with either a knife or a gun, reason given for giving Mitch a choice on how he is to be killed is because it is Christmas.
SIG P225
Waldman has a SIG P225 pistol which Mitch Hennessy (Samuel L. Jackson) later uses against Daedalus (David Morse).
Smith & Wesson Model 29-2 snub revolver
A thug falls with a large framed snub revolver that is bright nickel. It is not well seen, but I will hazard an guess that is is a 2" S&W Model 29 revolver that is nickel plated. Though seen briefly it is a very large framed revolver and being bright nickel would not be any of the Stainless models.
Beretta INOX
Charly and Timothy fight over a Beretta INOX - either 9mm or .40 S&W.
Smith & Wesson Model 19 Snub revolver
Nathan Waldman (Brian Cox) carries a S&W Model 19 Snub Revolver - .357 magnum.
Beretta 92FS
Multiple assassins and Mitch Hennessy used the Beretta 92FS - 9mm]]
Desert Eagle .357
One Eyed Jack (Joseph McKenna) loses his eye (hence his name) and tries to kill Charly Baltimore for it with his .357 magnum Desert Eagle.
Steyr TMP
Killers use a Steyr TMP submachine gun - 9mm.
AR15 Patriot Pistol
One of the killers seems to be using a full auto version of the early 1990s Rocky Mountain Arms Patriot pistol with 7" barrel - 5.56mm
Beretta M12
The killers also carry Beretta M12 submachine guns - 9mm
Olympic Arms OA93
Some of the killers also carry and fire Olympic Arms OA93 pistols converted to full auto.
Walther MPL
Briefly seen during the arrival of the bad guys at Daedalus' estate.
Heckler & Koch MP5K
Mini Uzi
Taken from one of the train station assassins, Charly uses the Mini Uzi to shatter the ice on a pond as she plummets from a building.
Uzi
Seen briefly, though many of the henchmen run and fight with a variety of weapons during the night battle.
Winchester Model 1894
Mitch Hennessy carries a Winchester Model 1894 lever action rifle - caliber unknown.
Colt 733 Carbine
Bad guys use the Colt 733 Carbine and Charly Baltimore also uses it with a scope at the night battle.
Ruger Mini 14
Charly Baltimore uses a Stainless Ruger Mini 14 ranch rifle with synthetic black stock, heat shield/barrel shroud and Stainless flash hider and scope.
Winchester 1887 Shotgun with M203 Grenade Launcher
A stranger combo cannot be described. One Eyed Jack (Joseph McKenna) tries to kill Charly Baltimore (Geena Davis) with an M203 40mm Grenade launcher attached to a Winchester 1887 Lever action shotgun. However, in the film, flip cocking the shotgun, somehow reloads the grenade launcher. Also when it fires, the projectile looks more like a guided missile than a grenade. The only truly ridiculous weapon in an overall good action flick.
M16A1
A very strange combination, Timothy while riding in the helicopter, uses an M16A1 rifle to shoot at Charly Baltimore on the bridge, but rather than standard handguards he has the special handguards designed for the M203 combination.
Heckler & Koch 91
One of Timothy's henchmen uses an HK91 rifle in the helicopter when they try to corner Charly and Mitch.
M26/M61 Grenade
Actually a pot metal training grenade, obviously from the markings. This grenade is thrown at Charly and Mitch, and shows all of traits of Hollywood Fantasy grenades. It has a 20 second delay, and packs the explosive power of twenty pounds of C4 and a 55 drum of gasoline.