Apache Rifles by Ethan Flagg
When Brick Shaftoe receives an urgent cable from his brother, he hurries to the town of Brass Neck in New Mexico, for it is there that the Apache chief, Mangonellis, is being supplied with guns to terrorize the smaller ranchers. Soon after, Brick discovers that his brother has met with a fatal accident and he is sure that this is no coincidence. Through his sorrow, Brick vows to find out the truth about what has been going on in Brass Neck...no matter how rocky the road is along the way.