Super Colt 38 (1969)

Billy Hayes, the marshal, discovers that the bandit whom he has been pursuing so long, and who has for months been torching his county, is none other than an old friend from childhood. Upon being confronted with the truth, the friend draws his gun, and Billy is forced to kill him in justifiable defense. Overwhelmed by guilt, he renounces his office and swears to never use arms again. He rides off toward the town where he and his old friend grew up together. Upon arriving there, he soon becomes involved in a dangerous situation, where Billy must decide whether he will fulfill his promise to keep away from arms, or intervene to save the honor of a woman and the life of an innocent man.