The Wild Bunch (1969)

It's 1913 and the old West, facing the march of progress is rapidly changing. A gang of aging outlaws led by Pike Bishop, who are one steal from retirement, ride into the town of Starbuck Texas dressed as Union soldiers, to rob a local railway office where a posse of bounty-hunting gunmen await. On the other side of the line, Pat Harrigan wants Pike and his men dead to make his railroad safe. Deke Thornton wants to capture Pike, his "get-out-of-jail-free card", and the gang of bounty-hunters want the reward money on the "Bunch's" heads. No one is innocent in this unflinching tale of desperation against changing times.

IMDb: https://www.imdb.com/title/tt0065214