Other mistake: Why did Merrimen have to show Donnie how to use a M4? Earlier in the movie it was stated that Donnie was in the Marines for a short time.
Other mistake: In the ending shoot out, Gerald Butler looks over cars with his rifle and the magazine is missing in one of the shots.
Other mistake: At the gun range, Merrimen is shooting very rapidly, heard by Nick and seen by us at times. Two problems with the scene - Merrimen fires in 6 clusters - 5 shots, then 9, 8, 8, 8, and 9 again. But he reloads between each cluster, and we see his slide lock back after the 8th shot at times, so how's he getting 9 rounds off sometimes? Plus we see the target he was shooting, with a close group dead center, but there aren't 47 bullet holes, nor larger holes where two bullets hit close together.
Other mistake: When they are back in the office after leaving the crime scene, Big Nick asks when was the last time "Merrimen" paroled, and they tell him 8 months. Then he asks what about that Wilson kid (Donnie) we put a tail that was hanging out with "Merrimen." I thought he didn't know Merrimen was out?
Suggested correction: Only Big Nick and the other cops knew Donnie had served. They had his records pulled up. Donnie never told the other crew so he could look inexperienced enough to not run the whole show. It made it easier to double cross both sides later. Donnie played the fool to get the upper hand.
50 cent told Merrimen "he was a marine for a minute" also Donnie has an Eagle, Globe and Anchor tattoo (Marine Corps).