Max Brand 
Way of the Lawless 

Published in 1919, this tells the story of Andrew/Andy, raised by his uncle to shoot and ride horses. Andrew is content with living a quiet life in a Western town, until a bully picks a fight. Andy knocks him out, and the guy hits his head on a rock. Andy goes on the run, thinking he’s a murderer and subconsciously gravitating towards the lawless sector. (Goodreads)