Factual error: In the early part of the movie, there is a shot of the outside of Triple O's bar. The scene takes place in 1975 and "Coors" is advertised on the outside of the bar. Coors beer was not available in Boston/East Coast in 1975. It was only available from the 1980's.
Black Mass (2015)
Plot summary
Directed by: Scott Cooper
Starring: Johnny Depp, Benedict Cumberbatch, Joel Edgerton, Dakota Johnson
The true story of Whitey Bulger, the brother of a state senator and the most infamous violent criminal in the history of South Boston, who became an FBI informant to take down a Mafia family invading his turf.
More mistakes in Black Mass
Officer Flynn: You threatening me, Bulger?
Whitey Bulger: The last thing I would do if I was planning to harm you was to warn you in advance, you dumb fuck.
Officer Flynn: You better watch yourself, Bulger.
Whitey Bulger: You better fuck yourself, Flynn.