The Wild Westerners(1962)

Sheriff Plummer and his men are using their badges to easily rob gold shipments and kill the drivers. Marshal McDowell and his men are looking for the killers. They catch one who is murdered to keep from talking but his killer is identified as Plummer's Deputy. Plummer is still not suspected when McDowell's wife is kidnaped and the outlaws demand the big gold shipment be sent unguarded. So McDowell heads out alone to face the gang with a load of gunpowder instead of gold and only a few trusted Deputies nearby.