Corrected entry: As Russell is about to enter the house in a search for a dangerous adversary he loads his shotgun from an ammo holder on the stock. This is an extremely poor tactical move, especially for a trained police officer. The shells on the stock are extras; the gun should have originally been loaded from another supply prior to entry.
Dark Blue (2002)
1 corrected entry
Directed by: Ron Shelton
Starring: Kurt Russell, Ving Rhames, Brendan Gleeson, Scott Speedman, Michael Michele
Continuity mistake: Toward the end of the film, Kurt Russell backs his car into an upturned car during the riots. The back right hand corner of the lights and boot lid are all screwed up. In a few scenes later, the boot lid isn't quite as screwed up and the light has magically fixed itself.
Det. Sgt. Eldon Perry Jr.: That's my daddy's gun... and the only reason this city's here is because they built it with bullets.
Correction: As you say, it's an extremely poor tactical move, not a mistake (except from the character).