The Fracas Factor, by Mack Reynolds (epub/Kindle)
Guns were illegal. Unless you were a member of Category Military, no one on Earth could own a gun. So who was shooting at Joe Mauser? And why?
He'd been a mercenary, but he'd been thrown out when he saved Field Marshal Cogswell's life. Whose enemies were after him now—his own, or Cogswell's? In a world where the computers kept track of you, Mauser had to disappear...and stay alive long enough to reach the Field Marshal!