Two Gun Sheriff (1941)

"Double daring! Double action! with your favorite action ace in a double role!"

A notorious outlaw is recruited by a cattle buyer, secret boss of a gang of cattle rustlers, to impersonate the town sheriff, who is the outlaw's twin brother; and complications ensue, as the sheriff, now a hostage, is on the eve of his marriage while the outlaw's cantina-dancer girlfriend has followed him to town and is at risk of exposing him.