Charles Bronson refused to play in the scene where he saves a naked woman. He refused because she was without clothes. Director Michael Winner eventually used a trick to make the scene without Bronson's agreement.
The Hooker ranch house and barn are the same as the McBain house and barn in Il était une fois dans l'Ouest (1968).
Charles Bronson refused to eat at the same table as Jack Palance during the shooting breaks. Towards the end of filming however, they did share an meal and Bronson was known to have said "Jack Palance is a very nice man". Bronson was known to be very guarded.
According to the book, "Bronson's Loose", director Michael Winner stated that this was the only film he made with Charles Bronson that Bronson enjoyed watching.