Michael Cheritto (Tom Sizemore), brings an Israeli assault rifle (based on the AK-47, but with improved sights, among other changes) known as an IMI Galil ARM with a folding stock to the bank heist. He gets separated from the rest of the crew during the gun battle but managed to wound one of Hanna's detectives by a transit bus.
Chris Shiherlis (Val Kilmer) takes out the Steyr TMP-wielding assassin at the drive-in with a .308 to the back from a Heckler & Koch HK91A2 fitted with a bipod.
FN FAL 50.61
Michael Cheritto (Tom Sizemore), brings a 20" barreled FN FAL 50.61 Paratrooper version with a Side-folding stock to the armored car robbery which he uses to execute the third guard.
FN FNC-70-30
Lt. Vincent Hanna (Al Pacino) pulls out an FN FNC-70-30 law enforcement carbine outside the bank heist on Flower Street. Michael Cheritto (Tom Sizemore) receives a 5.56mm present between the eyes from Hanna's FN FNC-70-30.
M16A1 (with M16A2 handguards)
Several M16A1 assault rifles feature prominently in the film, fitted with M16A2-style handguards. They are wielded by various L.A.P.D. officers, including Detective Casals (Wes Studi). Casals uses one to assist in disabling McCauley's getaway vehicle (a Lincoln Town Car) and injure Chris Shiherlis (Val Kilmer) during the gun battle resulting from the bank heist. According to the on set armorer, the director wanted the actors to fire semi-auto only. The reason given was that the police would be less interested in 'suppressing fire' and more interested in controlled shots given the proximity of so many innocent bystanders.
Colt Model 654
During the armored car heist, McCauley and Shiherlis (Robert De Niro and Val Kilmer) carry Colt Model 654 carbines, 14.5" barreled predecessors to the M4, with M16A1-style lightweight barrels and sights. Based on configuration it may be a 654 upper on a GAU-5A receiver (or possibly even an SP1 receiver with a drop-in autosear to allow it fire fully-automatic). McCauley (Robert De Niro) has Duct Tape wrapped around the handguard of his.
Colt Model 733
During the bank robbery Neil McCauley (Robert De Niro) and Chris Shiherlis (Val Kilmer) carry short barreled M16 rifle series carbines, which are designated as the Colt M733. They are ultra-compact versions of the M16 rifle family with 11.5-inch barrels, being smaller and shorter than the M16A2 Rifle (20-inch) and M4 Carbine (14.5-inch). The lighter encumbrance comes at a trade off of reduced range and accuracy, which is appropriate since the Model 733 can be fired from inside the vehicle, the robbers burdened by loads of cash, and because the firefight takes place at close to medium distances. The M733s have full automatic and semi-auto fire modes, while retaining the penetration of the 5.56mm round of its big brothers, which is particularly deadly as they are capable of wounding officers and bystanders even through objects normally considered safe cover. They handle similarly to submachine guns, however they are more accurate and much more powerful. Especially considering that submachine gun engagement ranges very rarely exceed 100 yards. Because at those short distances, the high velocity and light projectile weight of the 5.56mm NATO round tends to cause violent fragmentation after entering muscle tissue. The fragmentation is often so intense that it is more of an explosion than anything, leaving a larger number of temporary AND permanent wound channels where the bullet's fragments passed-causing incapacitaion much more rapidly. This tendency grows when using expanding bullets (i.e. Hollow Point, Polymer "Ballistic" Tipped). This is a very professional choice of a primary weapon for that particaular job, time and envirenment.
Not surprisingly, Shiherlis uses the M733s to great effect, killing Bosko (Ted Levine), a member of Hanna's detectives, in a brief exchange of fire. After the getaway ride is disabled, Shiherlis sprays the police barricade with dozens of rounds, shooting up the LAPD patrol cars and bringing down several officers. McCauley also uses it to shoot a pursuing patrolman while carjacking a Ford Taurus Wagon to escape.
Mossberg 590
Detective Casals (Wes Studi) brings a Mossberg 590 to breach the door of Hugh Benny's (Henry Rollins) apartment. Sergeant Drucker (Mykelti Williamson) appears to carry the exact same Mossberg 590 in the firefight outside the bank heist. Lt. Vincent Hanna (Al Pacino) takes one from an officer towards the end of the film as he chases down McCauley at the airfields.
Neil McCauley (Robert De Niro) can be seen carrying a Heckler & Koch USP45 chambered in .45 ACP (noted by longer grip and barrel) in the early scenes of Heat. Note the checkered back of the grip and the shape of the external thumb safety and slide release, all uncommon to a SIG P220. It is usually not seen clearly during the film, but the shape of the slide can easily be discerned during the shootout at the drive-in (when McCauley fires the gun through the window of his sedan at the shooter with the Steyr TMP).
Star Megastar
Waingro (Kevin Gage), the unstable newcomer to Neil McCauley's (Robert De Niro) crew, carries two Star Megastars; the first is blued, the second stainless.
Steyr TMP
The shooter at the drive-in (Max Daniels) brings a Steyr TMP 9mm, attempting to kill Neil McCauley (Robert De Niro) during the cash exchange.
Glock 19
After McCauley kills Waingro, a detective working surveillance at the hotel draws a Glock 19 on McCauley, only to be expertly subdued and then dissarmed.
Heckler & Koch SR9(T)
A police sniper of the servaillance team watches over McCauley with a Heckler & Koch SR9(T) sniper rifle. This same sniper is seen during the stakeout for Shiherlis with the rifle.
Heckler & Koch MP5A3
Heckler & Koch MP5A3s are seen held by a L.A.P.D. SIS surveillance unit member hiding in trash during the stake out scene at the metals warehouse.
It is also used by a surveillance team watching for Shiherlis and is used by the SWAT team that is sent to the hotel in the climax.
Taurus PT92
A stainless Taurus PT92 can be seen in the holster of the bank guard whom McCauley kicks to the floor during the robbery scene.
Ithaca 37 "Stakeout"
An Ithaca 37 "Stakeout" short-barreled shotgun can be seen resting behind a security desk when McCauley goes to kill Waingro in the apartment building.
Ruger KP90
Michael Cheritto (Tom Sizemore) has a Ruger KP90 in a cross draw hoster on his tac vest while he is armed with the FN FAL, during the armored car robbery. This is NOT the P90, as sometimes claimed, but the stainless KP90.
Smith & Wesson Model 38 "Bodyguard"
A Smith & Wesson Model 38 "Bodyguard" is pulled from an ankle holster by one of the armored truck guards before being shot by McCauley.
M1911A1
One of the SIS officers checking Shiherlis' car has an unknown M1911A1 pistol in his holster. Since Kimbers weren't issued yet to LAPD officers, it is doubtful it is a Kimber Cusom II.
Shiherlis' Pistol
Shiherlis is seen with an unknown compact pistol in a holster next to him when McCauley walks in and sees him sleeping on the floor. He wakes up and then sticks the holstered gun in his pants. The closest gun it seems to resemble is a SIG-Sauer P228