The Last Round-up.

Randolph Scott plays Jim Cleve, one of several volunteers keeping the US-Mexican border safe on behalf of American settlers. Ostensibly the hero, Cleve is actually out-heroed by the film's nominal villain, outlaw leader Jack Kells (Monte Blue). It is Kells who brings about the story's happy ending, sacrificing his own life to ensure the blissful future of young lovers Cleve and Joan Randall (Barbara Fritchie).