The Wild Bunch (1969)

Aging outlaw, Pike Bishop prepares to retire after one final robbery. Joined by his gang, Dutch Engstrom and brothers Lyle and Tector Gorch, Bishop discovers the heist is a setup orchestrated in part by a former partner, Deke Thornton. As the remaining gang takes refuge in Mexican territory, Thornton trails them—resulting in fierce gunfights with plenty of casualties.