At WorldCon this year, I attended a panel on military SF, at which it was mentioned that a team of authors who wrote such books that rang true for experienced soldiers were David Sherman and Dan Cragg, who write the Starfist series of novels. I'd seen them around, but had never picked any up. Subsequently, I found the first book of the series (in the Bay Area, of all things! Who'd have thought that???); I finished reading it this morning.
Vivid combat descriptions; the chapters on the training were also easy to visualize. I will be hunting up the other books of the series to read.