Some scenes were shot in the same Western location town as Howard Hawks's final film, Rio Lobo (1970). Michael Winner says in his autobiography that the crews of both films met in the middle of the town, as in a Western showdown, but without guns.
When Maddox (Burt Lancaster) is taking Vernon Adams (Robert Duvall) in after wounding him, they pass by a horse being eaten by coyotes. You can see the front two legs tied on one coyote.
Lee J. Cobb, who always wore a hairpiece in his films, agreed not to wear a wig for the film at the request of director Michael Winner.
One night, during the film's pre-production phase, director Michael Winner stood up and went for a pee because he refused to use a caravan with toilets. When he relieved himself in the darkness, he did it over a Mexican crew member sleeping on the floor. The man suddenly woke up and began shouting and grabbed a knife. Michael Winner says in his autobiography that this was the scariest experience of his whole career.
There was a serious argument between Burt Lancaster and director Michael Winner while filming the scene where Lancaster shoots a horse. Lancaster first used a Colt 45 and after a short break, resumed the sequence using a Winchester 73 rifle. Winner told him so and Lancaster then threatened him to kill him by throwing him from the edge of a cliff. Winner finally agreed to say that Lancaster actually used a rifle for the first take. But during the evening rushes, Lancaster told that there was something wrong in the scene, since both the Colt 45 and Winchester were used. Winner then reminded him of their earlier disagreement and Lancaster told him he did not know what he was talking about.