As American troop casualties in Iraq continue to mount, concern is growing they may be outgunned. That includes new questions about the stopping power of the ammunition that is used by the standard-issue M-16 rifle. Shortly after the U.N. headquarters was bombed in Baghdad in August 2003, a Special Forces unit went to Ramadi to capture those responsible. In a fierce exchange of gunfire, one insurgent was hit seven times by 5.56 mm bullets, reports CBS News chief investigative correspondent Armen Keteyian. It took a shot to the head with a pistol to finally bring him down. But before he...