Trap Angel!

The renegades had hit three Army posts. All they took were guns and ammunition: until the last raid. That time they got away with a Gatling gun. Now, somewhere out there, was a gang with enough firepower to take on the United States Army. Find them, the Justice Department told Angel. And stop them.
What they didn't know was that out of the empty, lawless land, every trigger-happy gunslick in the territory had been given the word: when you see him coming, trap Angel. And kill him.
Third in the Frank Angel series written by the author of the popular Sudden western series.