Other mistake: In the scene following the robbery, the four young men, led by Tupac Shakur and Omar Epps, run into a brick court, walled on four sides. Shakur states he's going to keep the gun, despite suggestions that they ditch it. He has a revolver stuck in his jeans, by his left hip. When he is challenged about keeping the gun, he pulls another revolver from his pocket, scuffles with one of his friends and shoots him in the chest - all the while the grip of the other identical revolver is in view.
Suggested correction: It looked like old man Quilles' gun that he must've taken off-screen after he killed him.
If you look at the movie again, Quiles' gun was a long nose revolver, Raheem's gun was a snub nose.
Other mistake: In the scene where Omar Epps goes to the DJ battle, the reporter that is reporting in the club states that the DJ's only have 20 seconds to do their things, but just before that, the counter behind the DJ shows 24 seconds. (00:42:10)