MAJOR PAIN 

Clint Adams's travels lead him to Gemmell, Idaho, where he renews his friendship with fellow gunsmith Peter Banks. Surprised to find Peter so prosperous in such a small town, Clint learns that the U.S. Army is one of his regular clients—and they've just commissioned him to develop a variation on the Gatling gun. 

Unfortunately, Peter's had no luck keeping his work secret. Also interested in the weapon is a gang of thugs in the employ of a mysterious man known only as the Major. And when Peter is wounded in a gunfight with these owlhoots, it's up to the Gunsmith to pull rank on the Major...