Detective Nick Chen (Chow Yun-Fat) carries a Beretta 92FS as his sidearm throughout the movie, even though in real life the Beretta is neither issued nor authorized for the N.Y.P.D. (it is likely this was done because the Beretta is a signature weapon in nearly all of Chow Yun-Fat's action movies, so he is undoubtedly quite familiar with it). Many of the Fukienese Dragon gang members (including John Kit Lee as Jack) also use the Beretta, including the Inox version.
The movie also features many of ISS's flashbulb "Non Gun" Berettas. Nick Chen is seen using one in several scenes, and Bobby Vu (Byron Mann), the Fukienese Dragons' leader, is seen using an Inox Beretta Non Gun in the opening of the film.
Glock 17
Detective Danny Wallace (Mark Wahlberg) carries a Glock 17 as his sidearm in the movie. All of the N.Y.P.D. officers seen in the film can also be seen carrying these pistols, and some of the Fukienese Dragon gang members use them as well.
The "Non Gun" Glock also appears in some scenes. An NYPD officer uses one in the shootout at the brothel, and Danny Wallace also uses one in the shootout on the ship at the end.
Smith & Wesson Model 60
In addition to his Beretta, Nick Chen (Chow Yun-Fat) carries a compact Smith & Wesson Model 60 revolver as a backup weapon in an ankle holster. It is seen several times in the film, most notably when he uses it to kill an Uzi-toting Fukienese Dragon after getting the drop on him during the shootout at the brothel.
Glock 26
During the opening shootout in the lamp store, one of the Fukienese Dragon gang members fires at Nick Chen with a Glock 26.
Winchester 1300
At the end of the car chase through Chinatown, Danny Wallace (Mark Wahlberg) grabs a Winchester 1300 to fire at the Fukienese Dragons' car.
Uzi
Many of the Fukienese Dragon gang members are seen using IMI Uzi submachine guns which have had their butt stocks removed (probably to make them easier to conceal).
H&K MP5A3
Some of the Fukienese Dragon gang members also carry Heckler & Koch MP5A3 submachine guns which, like their Uzis, have had their butt stocks removed and replaced with stockless butt caps. One of these weapons is used by a gunman who fires at Nick Chen during the lamp store shootout, only to be taken down by Chen's Beretta. Bobby Vu (Byron Mann), the leader of the gang, also uses an MP5A3 when his crew goes to Uncle Benny's (Kim Chan's) house to kill him.
Smith & Wesson Model 686 Snub Nosed
When Uncle Benny (Kim Chan) hears the Fukienese Dragons breaking into his home and killing his bodyguards, he reaches into a dresser drawer and pulls out a stainless Smith & Wesson Model 686 revolver with ivory grips and a snub nosed barrel. When he sees that the Fukienese (who are armed with automatic weapons) have him out-gunned, he kills himself with his 686.