Stick to Your Guns (movie, 1941)

The Bar 20 boys are after Nevada and his gang of cattle rustlers. Hoppy and California join Nevada's gang under assumed names. Johnny and the rest of Bar 20 get directions from Winters and head out looking for Hoppy's signal. But Winters wanders on ahead and gets spotted. This lets Nevada trap them in a canyon and to make matters worse, Hoppy's masquerade has been exposed.