A Colt Detective Special revolver is the standard sidearm of the HKPF Crime and Security Department officers in the film. Near the end of the film, Inspector Lau Kin-Ming (Andy Lau) is armed with this revolver before being disarmed by Chan Wing-Yan (Tony Leung Chiu Wai).
Smith & Wesson Model 10
Smith & Wesson Model 10 revolvers are the standard sidearm of uniformed officers of the Hong Kong Police Force. The weapon is seen at the end of the film when Inspector Lau Kin-Ming (Andy Lau) leaves the elevator to meeting uniformed officers. It seems as though some officers carry the standard version of the Model 10 while others are equipped with the heavy barreled variant.
Colt Lawman Mk III
A Colt Lawman Mk III is seen in the hands of a police officer in the lobby. It is used to stand in for the Smith & Wesson Model 10.
Glock 17
Chan Wing-Yan (Tony Leung Chiu Wai) carries a second generation Glock 17 in the final scene when he holds Inspector Lau Kin-Ming (Andy Lau) hostage on the rooftop. A well known goof to the audience is when Chan draws his Glock on Lau, it clearly has no magazine, but in later shots his Glock has a magazine. The Glock 17 was the one of the standard sidearms of HKPF officers in the criminal investigation units at that time the film was released.
Taurus PT92
Taurus PT92 pistols are used by Triad gangsters throughout the film, notably in the shootout immediately following Superintendent Wong Chi-Shing's (Anthony Wong Chau-Sang) murder. In reality, the Triads use Tokarev TT-33 pistols instead, rather than the Taurus.