...and they say we shooters don't read anything but Guns and Ammo !

(Hey, I read Handloader too...)
I'm happy to see some of my favorites noted here. I read American history most of time, and when I do read fiction I still want the historical accuracy in the backdrop. That goes a long way towards making the story more readable.
A few of the guys here mentioned Allen Eckert. Try his "That Dark and Bloody River." Eckert has been criticized because he "fleshed out" much of his work with dialogue which is most likely to be close to what would have been said during specific times, but there was no one there to actually document it. I say, so what ?
I've jumped around in the book noted above, and one of the sections which knocked my socks off was his recounting of Lewis Wetzel's exploits. Wetzel lived in the Ohio River Valley, and had experienced much grief in his young life from Indian attacks. He turned to hunting them, and developed the skill of learning to load his flintlock while on the run. Very useful for turning the tables on an enemy while being pursued. Incredible stuff.
I also like the Stephen Hunter books, even if he gets all of his firearms input from others. The book about Bob Lee Swaggert's dad, Hot Springs, is really good. About the only real goof that I've spotted in a Hunter book was when he had Bob Lee unearthing a cached rifle he'd hidden in the woods near his Arkansas home. It was a Ruger Mini - 14, and Hunter goes on about how Bob Lee chose it for its accuracy. Ooops ! Hey, I like Mini - 14's, and I've owned three of them over the last decade. But very few of us who've owned them will ever brag from the rooftops about their accuracy. Small potatoes really. Hunter's books are still pretty enjoyable.
I'm going to check out some of you guys' recommendations. - DixieBoy
When the People Fear Their Government There is Tyranny; When the Government Fears the People There is Liberty.