A Gun for One Hundred Graves (1968)

Original title: Una pistola per cento bare

At the end of the Civil War, Jim Slade, a young confederate soldier and conscientious objector, returns to his ranch to find his parents murdered and the ranch practically destroyed. He finds and kills three of the murderers and learns the name of the fourth, a certain Corbett. Finally he discovers Corbett as the leader of a gang that has plans to rob a local bank and is invited to help defend the town from the bandits. Teaming with a preacher, who has an agenda of his own, the two take a stand against Corbett.