Army and Marine troops battling insurgents in the streets and urban neighborhoods of Iraq now have a potent new weapon at their disposal, thanks to the rocket scientists at Lockheed Martin Missiles and Fire Control in Grand Prairie. A recently released video shows U.S. troops in an unidentified Iraqi city under fire from snipers in the upper floors of a three-story building. An Abrams tank fires several rounds with its heavy cannon at the building, with little or no effect on enemy fighters. A few minutes later, an explosion rips through the building and eliminates the insurgents. The close-quarters urban...