In the opening scene, just after the man is set afire he falls to the ground. Frank shoots him and while firing his weapon jams. A casing is stuck in the ejection port (called a stovepipe when it happens). After the round sticks he continues to pull the trigger and the weapon continues to fire.
Ruby Dee was nominated for the Best Supporting Actress Academy Award for her role as Mama Lucas, even though she's only on screen for less than 10 minutes.