First, the only copies I could find were at the Internet Archive and on YouTube. The available copies run 48 minutes but according to the IMDb, Law of the Rio Grande originally had a 57-minute run time. If that number is correct, that means that the versions on the Internet Archive and YouTube are missing 9 minutes. Since there doesn’t appear to have been anything objectionable in the film (this is a 1931 b-western, after all), I’m going to guess that the 9-minutes were probably cut when the movie started playing on television in the 50s. That is something that happened to a lot of the old western programmers. Television was quick to buy them because they were cheap and they made for appropriate children’s programming but the movies were always edited for time and often, the original versions were lost.
Secondly, edited or not, Law of the Rio Grande is not very good. It was made, for a very low-budget, by Syndicate Pictures, a poverty row studio. The majority of the cast was made up of actors who had found success in the silent era but who never made the adjustment to the sound era. Though the actors have the right look to play cowboys, none of them know how to actually make dialogue sound convincing. There’s also a persistent sound of crackling static in the background of most of the scenes. I don’t know if that’s the fault of the film or if it’s just a bad upload but it’s obvious that the cast and crew of Law of the Rio Grande were not used to working with sound.
Despite the film’s title, the Rio Grande was nowhere to be seen in the version that I saw. Instead, the film is about two outlaws, Jim (Bob Custer) and Cookie (Harry Todd), who are determined to go straight. Jim and Cookie end up working for Colonel Lanning (Carlton S. King) and his daughter, Judy (Betty Mack). But then a former acquaintance known as the Blanco Kid (Edmund Cobb) shows up and threatens to reveal the truth about Jim’s background. It’s a typical western programmer, with the main message being you can’t escape your past but you can beat it up in a fair fight.
The kids probably loved it in 1931. Today, it’s mostly interesting as an example of one of Bob Custer’s final films. Custer was a legitimate rodeo star who went to Hollywood during the silent era and who had a lot of success because he looked authentic jumping on a horse. Like many silent era stars, he didn’t have to actually recite or even know his lines. He just had to be himself. Unfortunately, the sound era destroyed his career because, while he may have looked like a character from the old west, he didn’t sound like one. Unable to find work at the major studios, Custer ended up making movies like this one for studios like Syndicate Pictures. He retired from acting in 1936 and went on to become a building inspector for city of Los Angeles. It turned out that he was a better engineer than he wan actor and eventually, he named Chief Building Inspector for the city of Newport Beach, California. He passed away in 1974, nearly forty years after starring in his final film. He was 76 years old.