Inspector Harry Callahan's (Clint Eastwood) primary weapon as expected is his ".44 Magnum", the Smith & Wesson Model 29 with an 6 1/2" barrel. He comments in the film to his partner Insp. Kate Moore (Tyne Daly) that he particularly favors this gun do to penetration power, since he claims he's seen a .38 ricochet off a car windshield.
Colt Python
The 2" barrel version of Colt Python is carried by Callahan's partner, Inspector Kate Moore (Tyne Daly), who keeps it in her purse. This revolver is also carried by many members of the San Francisco Police Department.
Judging from the revolver's hammer shape, I should say that it is a Diamondback, not a Python
M72A1 LAW
M72A1 LAW rocket launchers are seen in the film, and are among the weapons taken from the depot by Maxwell (DeVeren Bookwalter) and his men. During the final battle on Alcatraz, Maxwell drops his LAW and it is picked up by Insp. Callahan (Clint Eastwood), who uses it to destroy the tower that Maxwell makes his last stand in. When the launcher is shown off to SFPD by a US Army instructor, the weapon is refered to as a "Laws", as if they imply someone by the name of Laws made it, as opposed to it being an acronym for "Light Anti-Tank Weapon".
Colt Trooper MK III
An SFPD officer is seen aiming his Colt Trooper MK III during the robbery at the beginning of the film.
Smith & Wesson Model 27
Callahan's first partner in the film, Insp. Frank DiGiorgio (John Mitchum), carries a large N-Frame Smith & Wesson Model 27 with a 4" barrel as his sidearm.
Ithaca 37
Bobby Maxwell (DeVeren Bookwalter) uses a sawed off Ithaca 37 shotgun to kill one of the gas station drivers at the beginning of the film. Later, an SFPD officer is seen using a full sized Ithaca while outside the liquor store being robbed.
M16 (SP1)
M16 (SP1) rifles (with both birdcage and three-prong flash hiders) are used by the SFPD officers that arrest the Uhuru group, and later are seen among the weapons stolen from the Hamilton Firearms warehouse by Bobby Maxwell (DeVeren Bookwater) and his terrorist group, The People's Revolutionary Strike Force. They later use the guns to abduct the Mayor (John Crawford) and hold him on Alcatraz.
Armalite AR-18
Several Armalite AR-18 rifles are used by the members of The People's Revolutionary Strike Force on Alcatraz Island.
Remington 870 Folding Stock
People's Revolutionary Strike Force member Wanda (Samantha Doane) disguised as a nun in the church Insp. Callahan (Clint Eastwood) goes to to investigate the priest tries to fire a Remington 870 Folding Stock on him before being killed by Inspector Kate Moore (Tyne Daly).
One of the robbers in the liquor store is seen using a Smith & Wesson Model 15 revolver. Later, Wanda (Samantha Doane) is seen holding up a bridge operator with one before killing him with it.
Colt Detective Special
As Maxwell and his men leave the Hamilton Firearms warehouse, a guard fires his Colt Detective Special at their vehicle before being run over.
Smith & Wesson Model 10
One of Maxwell's (DeVeren Bookwalter) men is seen holding a Smith & Wesson Model 10 while waiting in the van to enter the Hamilton Firearms warehouse. Later, one of The Mayor's (John Crawford) guards fires a snub nose version before being killed.
M1911A1
The man who bombs the police station and flees from Insp. Callahan (Clint Eastwood) on the rooftops is seen armed with an M1911A1.
Unknown Pistol
While in the Hamilton Firearms warehouse, Miki (Jocelyn Jones) tries to draw an unknown pistol from her waist before being ordered to drop it by Insp. DiGiorgio (John Mitchum).
Federal Industries Model 201Z Tear Gas Gun
Insp. Frank DiGiorgio (John Mitchum) fires a gas canister from an Federal Industries Model 201Z Tear Gas Gun into the liquor store during the robbery.