Another author trying to write a techno thriller without doing basic research on the US military. Regiments in the US Army are ceremonial terms, the US Army operates in brigades/ Brigade combat teams. The only Regiments you will see will be in Cavalry units, if the ACRs come back. A Gunner is a title in the USMC, not a rank and it is a title for a Warrant Officer, not an E7 Gunnery Sergeant or an E9 Master Gunnery Sergeant. These are easy things. Some may fault the writings of Tom Clancy, LarryBond or Dale Brown, but at least they did their research. I have 10 hours left in the book, I’ll finish it because I paid for it.