found this on another site. Interesting.
http://www.subguns.com/boards/semimsg.cgi?read=132762
Have a close friend that was a security contractor for Custer Battles in Iraq in late 2003/2004. At one point he was performing armed security patrols during the repair of of salt water de-sal plant. He was shooting the shit with one of the gate officers when they took small arms fire from a building about 400-500 meters away. My friend felt a sharp pain in his upper chest. At the same time he looked down and saw a mettalic object fall from his field jacket onto the ground. He heard the muzzle report,realized what had happened, took cover, and returned fire on the area of the building they thought the shots came from and requested assistance over the radio. As luck would have it an Army National Guard patrol was almost right beneath the 3rd story window when the terrorist began firing. They assumed he was firing at their patrol. They quickly engaged and killed two shooters one of which had a captured M-4 rifle that had been lost 4 months prior, the other had an AK-47 that did not appear to have been fired recently. When it was all over my friend retrieved the metallic object from the ground. It was a fired, near pristine 62 grain M-855 U.S. issued bullet. My friend inspected the hole in his field jacket. If you know anything about C.B.'s it won't suprise you that he had no body armor. What was amazing or not was that the M-855 round had penetrated his field jacket and nylon strap of his web gear. The bullet was stopped when it hit His I.D. card which was one of those commonly used 2-3 mm thick plastic "Door swipe" or "Proximity" cards produced by HID Corp. The card was cracked and he had a bruise similar to that of being struck with a paintball.