Riders of the Rockies (1937)

A short (~1hr) Tex Ritter B-Western. He—and two "comedy" sidekick friends—are members of the Arizona rangers who are aiming to stop a cattle rustling gang. He does this through a slightly implausible pretending-to-be-a-baddie method.

To an extent these things have to be judged according to the time and style in which they were made. However, I wasn't a fan of this – the plot doesn't really hold up under any kind of scrutiny, there's a lot of unnecessary fast-forward, and everything is resolved by convenience in the end.