military system at the same time would be problematic and the request was rejected. In October 1961, William Godel, a senior man at the Advanced Research Projects Agency, sent 10 AR-15s to South Vietnam. The reception was enthusiastic, and in 1962, another 1,000 AR-15s were sent. United States Army Special Forces personnel filed battlefield reports lavishly praising the AR-15 and the stopping-power of the 5.56 mm cartridge, and pressed for its adoption. By intentionally choosing a slow twist rate the 55 grain bullet used in the 5.56 Ball M193 cartridge was only just stable in flight. The damage caused by the 5.56 mm bullet was originally believed to be caused by instantaneous "tumbling" on impact and render a wide, incapacitating wound due to the slow 1 in rifling twist rate. However, any pointed lead core bullet will "tumble" after penetration in flesh, because the center of gravity is towards the rear of the bullet. The large wounds observed by soldiers in Vietnam were actually caused by bullet fragmentation, which was created by a combination of the bullet's velocity and construction. These wounds were so devastating that the photographs remained classified into the 1980s. However, despite overwhelming evidence that the AR-15 could bring more firepower to bear than the M14, the Army opposed the adoption of the new rifle. U.S. Secretary of Defense Robert McNamara now had two conflicting views: the USAF's (General LeMay's) repeated requests for additional AR-15s and the ARPA report favoring the AR-15, versus the Army's position favoring the M14. Even President Kennedy expressed concern, so McNamara ordered Secretary of the Army Cyrus Vance to test the M14, the AR-15 and the AK-47. The Army reported that only the M14 was suitable for service, but Vance wondered about the impartiality of those conducting the tests. He ordered the Army Inspector General to investigate the testing methods used; the Inspector General confirmed that the testers were biased towards the M14. In January 1963, Secretary McNamara received reports that M14 production was insufficient to meet the needs of the armed forces and ordered a halt to M14 production. At the time, the AR-15 was the only rifle that could fulfill a requirement of a "universal" infantry weapon for issue to all services. McNamara ordered its adoption, despite receiving reports of several deficiencies, most notably the lack of a chrome-plated chamber. After minor modifications, the new redesigned rifle was renamed the