Gail Russell was actually a very good actress, but her "camera fear" was just too strong to be overcome and, as we all know, the results were tragic. There are stories that she was indeed "altered" during several films in order to play at least some of her scenes. One of these instances is purported to have occurred on THE LAWLESS, where she is actually quite good playing an erstwhile Latina reporter.
Possibly the most metaphorical scene of her career is to be found in THE TATTERED DRESS: an intense cross-examination scene where she is relentlessly questioned by Jeff Chandler, who presses her with startling urgency, resulting in her physical collapse on the witness stand. It's the best scene in the film.
I really like BLOOD ON THE MOON--a great cast from Mitchum on down. It also provides tangible proof that Barbara Bel Geddes was not always the mousy girlfriend...