I like the verse too, Brian. Just a couple of points, though. Soldiers don't carry guns, they carry rifles (at least in my army - I stand corrected if it's not so in the U.S. Army). Also, a soldier on active service would probably not go on a fighting patrol like "it was just another day", at least not if he hoped to stay alive. Since you need the line to end with "day", how about "I was on patrol before the break of day"?

Edmund