Mac (Isaiah Washington) is seen carrying a Walther PPK/S in an ankle holster as one of the many guns he carries throughout the film. With the two revolvers and the SIG-Sauer P226, that makes four guns he seems to carry around.
Maurice (Anthony Anderson) uses a chrome-plated IMI Desert Eagle with a black safety and hammer. In one scene where he tries to draw this gun on Han (Jet Li), Han disarms him and throws the gun away. Maurice later gets another one (or maybe just happens to find the gun Han threw away later). This gun is also used by a gangbanger in the club at the beginning of the movie.
Heckler & Koch MP5Ks are seen in the hands of the Chinese gang and the black gangsters. Both sides had the PDW stock. The NFL bodyguard had a regular MP5K with a brass catcher at the end of the movie in the helicopter.
A Cobray M11/9 is used by one of the Asian assassins on a motorcycle. It seems to be the same nickel-plated Cobray also seen in American Dragons (which makes sense because Rob Fournier was the armorer on this film and that one, according to the credits).
A bodyguard protecting Vincent Roth (Edoardo Ballerini) at the end uses a compact assault rifle hidden in a suitcase. This is a modified Olympic Arms K23B AR-15 "stubby" with a cut-down front sight and a suitcase-style carry handle affixed to the flattop upper receiver.
Error creating thumbnail: File missingAn Olympic Arms K23B similar to the one seen in Romeo Must Die. The one in the movie has the M4A1-style flat top receiver with a suitcase handle on top of the receiver, whereas this gun has an A2 receiver and the newer-style collapsible stock. This one also lacks the cut-down front sight of the movie gun.Error creating thumbnail: File missingRoth's bodyguard pulls his Olympic Arms K23B from its suitcase. Note the "Stowaway" pistol grip and white lettering on the magazine well, both common features of older-model Olympic Arms AR-15s.Error creating thumbnail: File missingThe bodyguard chambers the OA K32B.Error creating thumbnail: File missingThe bodyguard points the K23B at Mac.
Olympic Arms K3B Commando
When the Asian and black gangsters all have guns drawn on each other at the beginning in the club, Silk (DMX) breaks up the fight by firing a shorty M4-type weapon into the ceiling. He then says, "Guns don't kill people, people kill people". This weapon looks similar to the Colt Model 933 (AKA the "M4 Commando"), but it is actually an equivalent from the Olympic Arms K3B series. It is recognized as an Olympic Arms rifle by the white lettering on the lower receiver and the four-prong "Phantom"-style flash hider.
Silk's bouncers in the club are seen using Colt XM177E2 carbines; however, the weapons look fake and plastic, which suggests they might be airsoft guns (unlike Silk's M4, which is definitely a real blank-converted weapon).