Harry Sherman, the original producer of the Hopalong Cassidy series at Paramount, occasionally was allowed to produce other westerns and Knights of the Range is one of his. In fact he got to use Russell Hayden and Britt Wood who were Hoppy's current saddle pals as players in this. Add to that Victor Jory who was a villain in a few of the Hoppy films and you practically have a Cassidy oater without Bill Boyd.
Russell Hayden is a likable young cattle rustler who's having some angst about the outlaw business, but it's all he knows. When the owner of a big cattle ranch he was rustling from is killed, he leaves the gang albeit with the blessings of leader Morris Ankrum who treats him like a son.
Victor Jory moves in and takes over the gang and Hayden's duty becomes clear. You haven't seen too many B westerns if you can't figure the rest out.
Hayden at one time was considered prime material for bigger things in the Hollywood cowboy world. However he could never rise above being Lucky Jenkins, Hopalong Cassidy's sidekick. But he certainly was good at that, the young occasionally hotheaded cowboy that Hoppy had to explain the given situation to.
The story is from the pen of Zane Grey our greatest American western writer. Grey's books still sell even if films aren't made from them any more. And he was so prolific, I seriously doubt if the movies filmed all of his work.
Knights of the Range played the bottom half of many a double bill, especially in Red state America. I can see this one at the bottom half of some Gary Cooper film Paramount would have released. Would have fit nicely.