The Smith & Wesson Model 36 is the revolver carried by LAPD Detective Ray Tango (Sylvester Stallone). In an homage to Jackie Chan's Police Story, he uses it in the opening sequence when facing down an approaching big rig that is transporting cocaine. He appears to be able to hit the windshield, and make a tight group, from a long distance, despite the poor sights on the gun. Tango also is seen taking the Model 36 from Federal Agent Wyler (Lewis Arquette) during a confrontation. Tango later gives Cash his revolver during the quarry chase.
Smith & Wesson Model 60
Tango also is seen pulling what appears to be a Smith & Wesson Model 60 from an ankle holster later in the film.
Smith & Wesson Model 15
Several FBI agents who confront Tango and Cash are armed with Smith & Wesson Model 15 revolvers.
Smith & Wesson Model 10
Other FBI agents who confront Tango and Cash are armed with Smith & Wesson Model 10 revolvers.
Ruger GP100
A Ruger GP100 revolver is carried by LAPD Detective Gabriel Cash (Kurt Russell). It's a stainless steel version fitted with an Imatronic LS45 laser sight.
A Beretta 92FS can be seen in the warehouse scene, when Tango & Cash are framed, being carried by one of the agents.
Detonics Scoremaster
Tango carries the Detonics ScoreMaster as a backup weapon to his S&W (even if it would make more sense to do the opposite).
Browning Hi-Power
The Browning Hi-Power can be seen being used by Cash (Kurt Russell). An error can be noticed in the roof scene. Cash pulls the slide back to put a round in the chamber, but the slide stays opened. In the following scene, the pistol is pointed at Requin's leg, but now the slide is locked. In the next scene however, the slide is open again.
Walther PPK/S
A stainless steel Walther PPK/S is Cash's backup gun. When he takes his handgun from his drawer, he mentions the someone must be messing with his gun because the sights are off. In this Walter, the rear sight is dovetailed into the slide and adjustable, but the front sight is fixed. When it is later found at a crime scene, the gun is fitted with a sound suppressor.
A heavily modified Heckler & Koch MP5A4 is seen used by both Tango & Cash at the end of the film. It's seen fitted with large scope and laser sight and with custom grips.
A Remington 870 folding stock is used by Cash to get the information from audio tech Skinner (Michael Jeter). The shotgun is also used by some of the prison guards when Tango & Cash escape.
Ithaca 37 shotgun
Seen in the hands of an LAPD officer at the beginning of the film.
Unidentified Short Barreled shotgun
A short barreled shotgun is used by the Chinese gunman.
Assault/Battle Rifles
M16A1
The M16A1 rifle can be seen both in the video about Det. Tango and used by some of Perret's guards, as well as in the warehouse. M16A1 rifles were also seen in the hands of the prison guards during Tango & Cash's escape attempt.
Ruger Mini-14
Heckler & Koch HK91
FN FAL
When Cash grabs some weapons from the LAPD R&D department, an FN FAL is seen in a gun rack.
Heavy Weapons
Fictional Gatling Gun
The vehicle Tango & Cash "borrow" is fitted with a what appears to be a six-barreled Gatling-type weapon. Judging from the bore, the weapon's caliber appears to be 30mm. Though rotary barrel auto cannons appear all over the world in similar calibers (mostly mounted on gunships) this is a purely fantasy weapon.
M134 Gatling Gun
During the quarry chase, what appears to be a real M134 minigun is used for when the truck mounted machine gun is actually fired.
M60D
M60D machine guns are seen mounted on the hood of Perret's trucks that chase Tango & Cash in the gravel pit at the end of the film.
Madsen machine gun
A Danish Madsen machine gun without a magazine is seen when Perret enters his gun warehouse.
Other
Shooting Boot
Cash is seen keeping a concealed firearm in the heel of his right boot. He uses this when confronting the Chinese gunman as well as later in the film.
M67 hand grenade
During an interrogation, an M67 hand grenade is seen taped to the mouth of Requin (Brion James). Another grenade is held by Cash during a fight with Requin.