Batman is the 1989 film adaptation of the Batman comic book character. Directed by Tim Burton, Michael Keaton stars as the Caped Crusader who matches wits with the Joker (Jack Nicholson). This cycle of Batman films would span 4 films (including Batman Returns, Batman Forever and Batman & Robin) before the "reboot" of the franchise in 2005 with Batman Begins.
The following weapons were used in the film Batman:
Bob (Tracey Walter) uses a Colt M1911A1 throughout the movie on several occasions. A random goon also uses one later in the movie.
Colt New Service
Jack Napier/The Joker (Jack Nicholson) uses a Colt New Service throughout most of the film including the BANG flag gun at the film's climax and flashback, where young Napier (played by Hugo E. Blick) shoots Bruce Wayne's parents. The only exception is one small edit when he pulls back the hammer in the Axis Chemical plant. A different revolver was used for this one shot.
The Joker (Jack Nicholson) uses a Smith & Wesson Model 15-3 with a custom 21 inch barrel to shoot down the Batwing. We later see that the gun has a telescoping barrel when the Joker collapses it.
Trivia: In Batman: The Brave and the Bold episode "Game Over for Owlman", the Joker is seen with a similar looking revolver from this movie. Also he tries to shoot Batman with it, only to reveal it is fake "BANG" flag gun which is another reference to this movie.
Smith & Wesson Model 19 Revolvers appear frequently throughout the film, notably in the hands of a mugger at the beginning of the film. Another Model 19 is seen carried by Lt. Eckhardt (William Hootkins).
Unknown Revolvers
There are a great many revolvers used in this movie, I will just post all revolver screens in this section, as I am no good at identifying them. Maybe someone else can.
I see Model 19s, Colt New Services, and Webleys. Maybe even more. - Gunmaster45
Hey there, decided the Batman page needed building, I'll try to split up the revolver section when I get more info, thanks for your help. - Diego Wolfwood
Could the police revolvers be a Colt Offical Police or a Smith and Wesson Model 10?
Webley Mk IV
Some of Joker's goons are armed with what appear to be Webley Mk IV revolvers in some scenes.
M1928 Thompson
The Joker's goons use M1928 Thompson Submachine Guns multiple times throughout the movie.
More Trivia: I also noticed this SMG is used a lot by bad guys in many episodes of Batman: The Brave and the Bold which is again another reference to this movie. To top it all off, I'm going to assume that every gun seen in the hands of bad guys is either from the WW2/Korean War era or is fictional.
Krieghoff Model L flare pistol
The Joker uses this weapon to shoot his TV, then proceeds to hand it to Bob.
Its probably one of those WW2 Japanese double-barrel flare pistols. Or possibly a German one
Browning M1919
The guns that pop out of the Batmobile's fenders are two Browning M1919's. Seen toward the end of the movie as the Batmobile is entering the chemical plant.
GE M134 Minigun
Batman (Michael Keaton) has a GE M134 Minigun equipped on the Batwing, and uses it to shoot at The Joker near the end of the movie.
Uzi
On Jack Napier's desk at his hideout, one of the photographs on his desk shows a dead soldier affected by one of the Joker's prototype gasses carrying what appears to be a Uzi with a unfolded stock.