The film stars Michelle Pfeiffer as Louanne Johnson, a former Marine who becomes an English teacher at an inner-city high school in California. Danny Glover plays George Grande, the tough but fair principal of the school. The film is based on the 1992 book of the same name by Johnson.
The scene you're referring to most likely occurs in the film Dangerous Minds.
In this scene, Louanne Johnson (Michelle Pfeiffer) is confronted by a Latino gang member named Emilio Ramirez (Renoly Santiago) who accuses her of being a racist. Emilio pulls out a gun and forces Louanne to play Russian roulette with him. Louanne eventually convinces Emilio to put the gun down and the two of them come to an understanding.