OK..I'll list them, should make them easier to find.
Revolution: "Rise to Rebellion" & "The Glorious Cause"
Mexican: "Gone for Soldiers"
Civil War: "Gods and Generals" & "The Last Full Measure"
WWI: "To the Last Man"
WWII: "The Rising Tide" & "The Steel Wave"
(there is a third novel in the WWII series, but I haven't read or heard about a publication date yet)
I've listed them by era and not his pub. dates.