Batman (1989)

The weapons seen in this 1989 movie are:

S&W 15-3

.38spl with custom 21 inch barrel

Smith & Wesson Model 1

Jack Napier (Jack Nicholson) uses this as his sidearm throughout the movie. He continues to use this as the Joker.

I only remember him using it in the scene when he shoots Bruce, the bullet stopped only by a metal tray he hid under his shirt. Depsite being a little .22 pistol, the gun made the typical movie gunshot.

Colt New Service revolver

Used by Jack Napier/Joker through most of the film including the BANG flag gun at the film's climax. The only exception is one small edit when he pulls back the hammer is the Axis Chemical plant. A different pistol was used for this one shot.

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.