I just listened once again to an interview online I'd heard in the past, from the radio program Open Source that's worth a listen:
It spends a lot of time talking with several seasoned combat artists--two marines and one civilian: Col. (Ret.) Avery Chenoweth, Steve Mumford, and then SSgt Michael Fay (who was in Iraq at the time) .
They really paint a fuller picture on what combat art is than what I could say. It's worth the time.
You can also look at some of the work of these artists on the Open Source website.