Inspector "Dirty Harry" Callahan (Clint Eastwood) returns with his ".44 Magnum", a Smith & Wesson Model 29 with a 6 1/2" barrel as his famous sidearm in the film. In the film, during the firing range scene, it is implied that Callahan's .44 loads are in fact .44 Special, and not Magnums when he states "It's a light Special. This size gun it gives you better control and less recoil than a .357 Magnum with wadcutters." However in this context, the dialogue could have meant that he used a 'light' .44 Magnum cartridge, possibly reloaded by himself. In the 2008 DVD release of the Dirty Harry series, writer John Milius comments that the "light Special" line was in fact misinterpreted by the cast and crew and actually meant he used a specially prepared lighter Magnum load.
The film marks the first time Callahan loses his trademark weapon, having surrendered it to Lieutenant Briggs (Hal Holbrook) near the end of the film, and presumably destroyed in a subsequent car explosion where it was left behind.
Colt Python
The four motorcycle cops of the "death squad", Officers John Davis (David Soul), Philip Sweet (Tim Matheson), Alan "Red" Astrachan (Kip Niven) and Michael Grimes (Robert Urich) carry 4" barreled Colt Python revolvers, as do just about every other officer of the SFPD. During the police shooting competition, Davis lets Insp. Harry Callahan (Clint Eastwood) try out his Python, in which he deliberately misses a target to analyze the slug with a ballistics microscope. At the end of the film, Lieutenant Neil Briggs (Hal Holbrook), using a Colt Python, confronts Callahan after losing his Model 19 Snub as well. In the film, the guns are shown capable of having a suppressor attached by sliding it onto the end of the barrel. Almost all revolvers have a gap between the barrel and cylinder which allows gases to escape, as well as sound, meaning they cannot be effectively suppressed. The device shown in the movie also seems to be attached to the weapon purely by friction between the barrel and the long side arms; it seems fairly likely that the first attempt to fire with it in place would shoot the device off the end of the gun were it actually trapping propellant gases rather than simply being a functionless barrel extension.
During the plane hijack, the two hijackers use Smith & Wesson Model 10 revolvers as their weapons. When Insp. Harry Callahan (Clint Eastwood) infiltrates the plane disguised as a pilot, he knocks out one of them and uses the gun to kill the other hijacker as he flees. Another Model 10 is seen in the hands of a robber during the Cost Plus stakeout scene.
Lieutenant Neil Briggs (Hal Holbrook) holds Insp. Callahan (Clint Eastwood) at gun point with a Smith & Wesson Model 19 Snub Nose while in his car. He loses it in the car chase scene when Callahan overpowers him and throws it out of the window.
Pistols
Beretta 951
One of the robbers during the stakeout scene in the Cost Plus uses a Beretta 951. A thug during the shootout in Frank Palancio's (Tony Giorgio) hideout, the shotgun-wielding thug tries to draw a Beretta but is killed by Officer Davis (David Soul) before he can fire off a shot.
Browning Hi-Power
Ricca's bodyguard during the start of the film tries to draw his Browning Hi-Power, but is shot before he can pull the trigger.
M1911A1
During the combat scenario in the police competition, one of the man targets is armed with an M1911A1.
Shotguns
Double Barreled Shotgun
When Insp. Harry Callahan (Clint Eastwood) and Insp. Early Smith (Felton Perry) are assigned to the stakeout mission in the Cost Plus, one of the robber holds a sawed off Double Barreled Shotgun with exposed hammers on Smith before the robber is shot by Callahan. During the shootout outside Frank Palancio's (Tony Giorgio) place with the police, one of Frank's men, Ed, uses a hammerless double-barreled shotgun, also sawed off. Due to continuity error, the gun fires off three shots from only two barrels.
Browning Auto-5
Another one of Palancio's thugs retrieves a Browning Auto-5 from the stored weapon before the shootout with the SFPD. It could also be the Remington 11 or the Savage 720, both of which are near identical clones by those companies.
Winchester Model 1897
Frank Palancio (Tony Giorgio) uses a Winchester Model 1897 to shoot an SFPD officer through the door of his hideout and spark the shootout with the SFPD. Another one of his men, Dickie, uses one as well.
Ithaca 37
The uniformed cop in the break room during the stakeout in the Cost Plus is seen using an Ithaca 37 shotgun while watching the robbery through the two-way glass. During the shootout with Frank Palancio's men, Early Smith uses an Ithaca with an 18" barrel and blade sights.
Submachine Guns
Smith & Wesson M76
A Smith & Wesson M76 submachine gun is seen used by Officer Alan "Red" Astrachan (Kip Niven) to kill a large number of underworld folks at a swimming pool party.
Trivia: Anyone who owns a copy of the DVD may note this scene is called "The Dead Pool" in the scene index, a play on the fifth installment in the Dirty Harry series, The Dead Pool.
M1 Thompson
One of Frank Palancio's (Tony Giorgio) thugs, Chuck, fires on the SFPD officers with an M1 Thompson before being killed by Insp. Callahan (Clint Eastwood). Another also fires on Callahan but it is harder to see and he is killed quickly.
The room at the police station used for Ballistics Analysis has a vast array of guns, many of which are obscured from view or are too difficult to identify.