Continuity: In the opening scene, the assassin is tracking the swimming girl through his gunsights. The gunsights are then removed and the camera just shows the girl from the same angle. However, when the girl is hit (perspective unchanged), the bullet hole is below the right shoulder and has to be from a bullet fired from at least 90 degrees to the right of the camera.
Continuity: When facing the cross in the park, Harry's shadow first is directly in front of him, then to one side.
Continuity: Before Harry clicks on the empty chamber towards the bank robber that "gots to know" you hear and see Harry pull the hammer back to fire in single-action mode but when the camera faces Harry and he actually pulls the trigger in double action as you see the cylinder spin again.
Revealing mistakes: When the Ford sedan at the bank robbery hits the flower stand and fire hydrant you can see the smoke from the "log cannon" that popped the car up coming out from the bottom. Later overhead shots show the wire coming from the trunk used to set off the charge and the wire runs off of the screen to the left.
Revealing mistakes: Picture of two kids behind Harry Guardino's desk is the same picture of two kids on Josef Sommer's desk, except two small pictures are jammed in the corner to camouflage it.
Continuity: Callahan finds the note at the beginning stuck on the prong of an antenna. While the note is being reviewed in the Mayor's office, there's no visible hole made by the prong.
Continuity: In the final bus scene, Callahan gets ready to jump onto the bus by walking to the far side of the rail bridge - when Scorpio looks up at him just before the bus reaches the bridge, you can see in the reflection of the windshield that Callahan is still standing on the near side of the bridge.
Revealing mistakes: When Scorpio robs the liquor store, the bottle that he was going to purchase is used to hit the clerk over the head and is empty.
Continuity: The bus driver announces herself as "Marcella Platt" over the phone during the hijacking, but the mayor's flunky, checking up on her, calls her Priscilla.
Continuity: As Harry crosses the street toward the downed bank robber, the shotgun is a few feet away from the robber's hand and well out of reach. A moment later after Harry delivers his famous lines, the shotgun is only a few inches away from the robber's hand, making it clear why the robber was tempted to go for the weapon.
Revealing mistakes: Throughout the first scene in the police station (where Harry first meets Chico), Harry is "drinking" from an empty coffee cup.
Factual errors: Dirty Harry refers to the 44 magnum as the "most powerful handgun in the world". It was not the most powerful when the movie was made and is still not today.
Audio/visual unsynchronized: In the scene after Harry jumps onto the bus, the bus goes into a gravel and dirt parking lot. Scropio whips the bus around and you hear the tires squeal like they were on pavement.
Errors made by characters (possibly deliberate errors by the filmmakers): When receiving first aid after the bank robbery, Harry insists on removing his pants so they don't have to be cut off and ruined. The pants were already ruined: he was shot in the leg.
Revealing mistakes: At the cross on Mount Davidson, Scorpio makes Harry toss his gun a good distance away onto concrete, which would cause noticeable damage to the revolver's blued finish. However, in the final scene (when Harry again delivers his famous speech,) there is no visible damage to the weapon.
Crew or equipment visible: Camera shadows falls across Harry as he climbs into the basket to rescue the jumper.