Jack Slater (Arnold Schwarzenegger) uses an IMI Desert Eagle Mark VII chambered in .50 Action Express (based on the bore diameter) throughout the film as his weapon of choice. The Mark XIX would later replace the Mark VII in using .50 AE, although there was a brief time in which the Mark VII was released in this caliber.
Extremely short barreled Minigun
An M134 with extremely short barrlels can be seen mounted on the side door of the black Toyota Previa Van for a few seconds.
Benidict uses a custom .357 Dan Wesson revolvers target pistol. It features a muzzle break compensator on the end of the barrel to dissipate recoil and improve accuraccy. It also has large, hand-hugging target grips, and adjustable target sights.
M3A1 "Grease Gun"
One of the thugs in the Red Ford F-100 chasing Slater uses an M3A1 "Grease Gun" when Danny Madigan (Austin O'Brien) enters the movie (literally).
MAC-11
When Danny day dreams about Jack Slater (Arnold Schwarzenegger) as Hamlet, he is seen firing a MAC-11 briefly before it switches to a MP5K. A thug in the red Ford pickup is also seen firing a MAC-11 from the right side window. They are noted as .380 MAC-11s based on thier size, but then again, Arny and this thug are pretty big dudes.
Heckler & Koch MP5K
When Danny daydreams of Slater in Hamlet, he is seen using an MP5K. One of the thugs on the pickup is seen using an MP5K. One of Benedict's thugs is also seen using an MP5K as well. The rest will be described in "The Funeral" section.
Intratec TEC-9
Some of Benedict's thugs in Slater's house are armed with TEC-9s. The man in Slater's closet is armed with a TEC-9 with a stainless barrel shroud. The rest are described in "The Funeral" section. They are noted as TEC-9s and not the full-auto TEC-DC9s because of the shroud mounted sling loop, not featured on the TEC-DC9. They were most likely converted to full-auto for the film.
Kimel AP-9
The closet assassin also holds a Kimel AP-9, a 9mm 'assault style' pistol that closely resembles the TEC-9/DC-9 series of guns.
Heckler & Koch HK33
The assassin in Slater's closet has an Heckler & Koch HK33 slung over his back.
Remington 870
One of the police officers outside Slater's second cousin Frank's house is armed with a Remington 870. A man in the back of the Ford Pickup is also armed with a Remington 870.
Beretta 92FS
Officers in the opening sequence are armed with Beretta 92FS handguns. The officer to the left outside cousin Frank's house is also armed with a Beretta 92FS.
Beretta 92FS Inox
A stainless Beretta 92FS Inox is seen in Slater's glove compartment.
Smith & Wesson 5906
When at Slater's apartment, he fires into his closet with what appears to be a Smith & Wesson 5906 handgun. Another Smith & Wesson 5906 is seen falling out of Slater's glove compartment.
When he fires, It sounded like the Desert Eagle, Right? I suppose this is just a Sound Error.
Slater pulls a .38 snubnose of unknown make and model off his person as he reveals what a walking arsenal he is in the opening scene with The Ripper.
Colt M1911A1
Slater tosses a Colt M1911A1 off of his personal portable arsenal called "himself" in the opening scene with The Ripper.
Savage 1907
Slater tosses a Savage 1907 to the ground when facing the Ripper.
Colt Mustang Pocketlite
Slater pulls a Colt Mustang off his ankle holster in the opening scene with The Ripper.
Colt Commando
At the opening sequence, SWAT team members are seen armed with what appears to be Colt Commando rifles, one of which is fitted with an M203 grenade launcher underslung. The Ripper throws one off the roof along with its user after emptying it into the police vehicles below The weapons' muzzles aren't seen so a definite answer isn't certain.
M16A1
A number of LAPD SWAT officers are seen with M16A1 rifles at the beginning of the film.
Heckler & Koch MP5A3
A SWAT team member in the opening scene is seen armed with an MP5A3 fitted with a Surefire dedicated fore end weaponlight. The rest is seen in "The Funeral Section".
Colt Python
A snub-nose nickel plated Colt Python is carried by one of Benedict's thugs and is taken by Whitney after she kills him. Another thug knocks it from her hands to the thug who can't catch, who not surprising, doesn't catch it, letting it roll into the kitchen. When Slater is shot with a shotgun in the vest, he falls and picks this gun up to shoot the man back.
Winchester 1300
One of Benedict's thugs is armed with a Winchester 1300 shotgun. He's the one who almost takes the marked bills and aims the 1300 at Skeezy at the front door.
Sawed-off Stoeger Uplander
The other thug who aims the gun at Skeezy at the front door is armed with a Sawed off Stoeger Uplander shotgun. The same guy shoots Slater in the vest with this shotgun, before being blasted with the Colt Python snub-nose.
SIG-Sauer P230
Danny decides to apparently take a SIG-Sauer P230 out of the glove compartment, and uses it to hold up John Practice before he pulls it from his hands.
Bren Ten "Peregrine Falcon"
John Practice's sidearm of choice is a tutone Bren Ten "Peregrine Falcon", a newer, improved update of the the Bren 10, which he uses to hold up Slater.
Walther PPK
Vivoldi's weapon of choice is a golden engraved Walther PPK which he uses to stop Danny for the second time from holding up Practice.
Franchi SPAS-12
Although hardly seen, one of Benedict's thugs has a Franchi SPAS-12, but not only does the gun leave the rest of the scene, we don't see this guy again either.(?!)
Slater pulls out a Mk 2 hand grenade to threaten The Ripper but he calls his bluff and orders Jack's son to pick up the grenade. A hidden blade pops out of the knife conveniently (because everyone has a grenade knife right?), and stabs the Ripper in the leg.
Fact: The grenade prop was composed of three basic designs. A regular dummy grenade, a grenade with a pop-out knife (noted by the obvious knife tip sticking out of the grenade in one shot), and a leg harness for the actor to wear to make it look like the knife was stuck in his leg.
THE FUNERAL SCENE
A scene in the film that requires its own section is the funeral scene, were an entire mob family is attending the funeral of Leo "The Fart". Everyone in the family pulls out a gun when Slater tries to take Leo from the funeral, being aware he is loaded with a nerve gas bomb. Guns already on the page are list here again to save space.