Stephen Hunter's Pale Horse Coming is now out in paperback. It is a great read if you like hard-boiled detective stories with lots of action.
Hunter's books are notable because he knows guns. You won't find the common laughable mistakes-- men bowled over 380 automatics, etc. Hunter is careful with the details-- it is not just a sniper rifle, it is a Model 70 in 30-06 or a Model 700 in 308.
The most interesting thing about this book is that Hunter fills his posse with gunwriters who are only slightly disguised versions of the real thing: a big bore revolver man from Idaho named Elmer Kaye, a tall Border Patrol officer from Texas named Bill Jennings, etc. Since i grew up reading the real life models, this conceit was a bonus. (And he seems to handle it pretty well).