While this all seems very plausible and intesting, I'm pretty sure it wasn't the IWS 2000 or any other type of Anti-Matrial rifle, most AM rifle's use Tungsten as a penetrator and this round had a motor on it. The Tungsten would have worn down too fast to do that much damage, now if it where a AM rifle it would more likely be a DU round that was fired, but even the U.S. doesn't use DU in anything smaller than 20mm, unless it's a Vulcan.