Try Alan LeMay.
He wrote The Searchers and The Unforgiven. While the movie adaptation of The Searchers is a classic, it suffers from hollywoodizing and oversimplifying the protagonist's hatred of the Comanche.
The Unforgiven movie ridiculously cast 31 year old Audrey Hepburn as a 16 year old Texas ranch girl...
Both novels are very authentic portrayals of the waking nightmare of the outer Texas frontier subjected to Comanche raiding in the 1860s.