The Beretta 92FS is the most common handgun in the film. Sgt. Frank Gannon (Dolph Lundgren) carries one as his sidearm, as does his partner, Billie Ross (Polly Shannon), along with nearly every other cop and thug in the film. Two assassins use suppressed Berettas at the beginning of the film to kill several prostitutes and an undercover agent. These pistols are replaced with Non Guns several times throughout the film.
Glock 17
Second Generation Glock 17 pistols are seen used by several cops, including Ed Grimes (Rothaford Gray) who wields one akimbo with a Beretta 92FS in the warehouse shootout. The cop who tries to bring in Ed has one holstered, though Frank swiftly relieves him and another officer of their weapons.
Smith & Wesson 5946
Captain Stone (Conrad Dunn) carries a Smith & Wesson 5946 pistol as his personal sidearm. He briefly uses it with a suppressor to kill one of his own men.
Submachine Guns
Heckler & Koch MP5
An H&K MP5 is briefly seen in the bag of guns Ross grabs from the dirty cop's car. Both it and the shotgun next to it are rubber props.
Uzi
Two would-be assassins use Uzis to try and kill Frank and Ross. Because they are very difficult to see, it's impossible to determine for sure the specific model, though they appear to be the full size variant.
Shotguns
Remington 870
What appears to be a Remington 870 can be seen when Frank retrieves two pistols from the dirty cop's weapons stash. Because most of the identifying features cannot be seen, its identity as a Remington is not confirmed.
Ithaca 37 Stakeout
An Ithaca 37 "Stakeout" is seen in the weapons stash. It is very obviously a rubber prop.
Mossberg 590A1 SBS
One of the dirty cops uses a Mossberg 590A1 SBS in a pistol grip only configuration during the warehouse standoff. Frank quickly (and brutally) relieves him of his weapon and then uses it during the ensuing gunfight.
Assault Rifles
IWI CTAR-21
The CTAR-21 is used quite frequently by Ross and Frank, and briefly by both of the CIA agents that they team up with. Ross first takes this weapon from the back of a dirty cop's car and uses it in the ensuing firefight. It is equipped with the standard MARS red dot sight and has olive drab furniture.
Colt M4A1
Colt M4A1 rifles are seen in the hands of a federal agent guarding LoPresti and Ed's family, as well as some of the dirty cops during the warehouse shootout. One of the guards at the deal near the end of the film has one fitted with an M203 grenade launcher.
Norinco Type 56-1
Several Norinco Type 56 rifles are used by both the dirty cops and their hired guns throughout the film.