The Beretta 92F is frequently seen in the hands of Jeffrey as in many John Woo films. However, according to one of the movie's armorers, they only had access to one Beretta 92F for most of the shoot, so the Brazilian Taurus PT92 was used in many scenes as a substitute.
Taurus PT92
A number of Taurus PT92s are used by Jeffrey and Sidney, including one stainless with wood grips. They are also used by many Triads.
There's a much clearer, better shot of the gun when the trigger is pulled and it clicks empty. -MT2008
I'll see if I can find it.
Ruger GP100
A Ruger GP100 can be seen used by Ying and few other police men.
Walther PPK
The Walther PPK is used by Jeffrey in his apartment as a backup alongside his Beretta, previously held in his left sleeve. The Walther PPK used in this scene was actually an 8mm German-made blank replica, because the armorers were unable to acquire a real PPK when the scene was filmed. Aside from a replica Desert Eagle seen in the weapons case and some model gun M16s visible in Sidney's armory, this is the only gun in the film that is fake.
CZ-75
A CZ-75 is in the hands of one of the gangsters who attacks Jeffrey at his apartment.
Can be seen in the house shootout use by the gangsters attacking.
Browning BDA9/FN HP-DA
Used by several Triad members in the nightclub shootout. Shortly after, it is used once again by Triads, Wong Tong (Wong Kwong-Leung), and Li Ying (Danny Lee) at the gun deal scene and the bus chase. The FN HP-DA continues to be used by Triad members throughout the movie. Near the end, Fung Sei (Chu Kong) briefly commandeers one in his attempt to retrieve Ah Jong's (Chow Yun-Fat) money from Wong Hoi (Shing Fui-On).
Smith & Wesson 5904
A suppressed Smith & Wesson 5904 is seen in the hands of a thug who attacks Jeffrey at his apartment. It possesses the squared trigger guard of early model 5904s.
A Desert Eagle is seen in the briefcase given to Jeffrey by Sydney. The Desert Eagle used in this scene appears to be an 8mm blank-firing replica.
Colt Python
A Colt Python is seen in the hands of Sidney when he gets Jeffrey's money for the last hit.
It looks more like a heavily modified s&w 629.
Smith & Wesson Model 60
A Smith & Wesson Model 60 with pearl grips is used by Jeffrey during his first hit.
Smith & Wesson Model 10
Carried by a police officer at the end of the movie.
Smith & Wesson Model 36
Used by Tsang Yeh and, at one point, commandeered from him by Ah Jong.
Colt Detective Special
Used frequently by Li Ying.
Beretta M12
A Beretta M12 sub-machine gun is used by Jeffrey and several Triad members in the house shootout
Heckler & Koch MP5K
A Heckler & Koch MP5K with two magazines clamped together is used by Jeffrey in the church, and later handed off to Ying. MP5Ks are also used by many of the Triads.
It is not a converted SP89 as stated previously. There's a very good close-up of him reloading the gun, and it clearly has the detachable SEF lower receiver. -MT2008
Uzi
One of the assassins at Jeffrey (Chow Yun-Fat)'s apartment uses an Uzi mounted with a sound suppressor.
Colt Commando M733
Colt Commando M733's are used by several of the Triad members in the battle at Fung Sei's house.
M16A1 (with M16A2 hand guards)
The first assassin at the beach that tries to kill Jeffrey (Chow Yun-Fat) after the hit on Wong Dung-Yu uses an M16A1 rifle that has M16A2-style hand guards. The rifle has a scope mounted on top of the carry handle and has a twenty-round magazine.
(Fake) SVD Dragunov
The rifle used by Jeffrey (Chow Yun-Fat) to carry out his assassination plot is a Chinese Norinco Type 56 assault rifle (AKM) that was visually modified to look like a SVD Dragunov. The armorers were unable to acquire a real SVD for the filming of the scene, so they were forced to use the Type 56 rifle instead. The rifle that Jeffrey drops into the sea was a Japanese airsoft AK-47 that was also modified to look like an SVD.
Norinco Type 56-1
A Chinese Norinco Type 56-1 is used in the church shootout by Inspector Ying.
Remington 870
A Remington 870, with a pistol grip in place of a standard stock, is used by Inspector Ying in the church shootout.
Sawed-off Remington 870
A sawed-off Remington 870 with a pistol grip can be seen in the hands of the bartender at Jeffrey's first hit of the film.
Franchi PA3
A Franchi PA3 is used by the syndicate killer in the church.