Stuart G. Yates 
Pursuers Unto Death [EPUB ebook] 

Gus Ritter is on his way south to avenge his brother’s murder. Facing gun battles with Comancheros and pursued by more than one posse, Ritter must use all his skill to survive.
Death stalks John Wesley Hardin like a wild beast, and an Okinawan’s deadly hands have brought him closer to the hangman’s noose.
As the dust settles, who will be the last man standing?