First Contract (War for Profit Book 1)

It's two millennia in the future and professional mercenary units dominate land warfare.
Sergeant Galen Raper arrives at the Jasmine Panzer Brigade welcoming center with high hopes for assignment as a tank commander. However, when he arrives he is assigned to the Brigade's home world mechanized infantry battalion and he has to serve a year as enlisted before he can apply for a commission as an officer.
From there it's wall to wall action, never a moment's rest, as is often the case for Soldiers serving their first enlistment. But then Galen is pulled up higher into the command structure and gets a bird's eye view and it all starts to make sense. A nice twist near the end puts Galen in a situation he's hardly prepared for and he's forced to rise to the occasion or accept defeat.