The Gambler Wore a Gun (1961)

The professional gambler Case Silverthorn wants to quit and retire to a small ranch in Marlpine he bought recently. On the way there he saves the Sheriff's life, who got into an ambush. However another man is dead, Will Donovan, from whom he bought the ranch! Neither the Sheriff nor Donovan's children know about the sale. So Case has to switch back to his former profession, while he tries to clarify the situation. He comes across a group of cattle thieves.