For education and discussion only. Not for commercial use.OUTSIDE BAGHDAD (Reuters) - Grinding hot gears and belching black smoke, the "hog" roared into life with only one destination in mind. "Baghdad or bust, baby, Baghdad or bust," muttered the U.S. Marine driver into the intercom. Tracks rumbling, armor plates rattling, the metal beast hammered up the highway. The machines -- Amphibious Assault Vehicles (AAVs) -- are now one of the strangest sights on the roads to Baghdad, thundering north in convoys taking Marines into battle. Ugly, brutal looking contraptions, the vehicles look something like a giant tank with a small...