American Rifle - Alexander Rose [206]
Thus, try as McNamara might to keep a lid on ever-increasing demand for the M16, American troops arriving in Vietnam in ever-increasing numbers placed ever-increasing pressure on the Pentagon to make a final, incontrovertible, irreversible decision on the M16’s status.79 McNamara’s placeholding option-three policy was slowly dissolving under the weight of changing realities. The June 1966 contract, for instance, would have to be amended 256 times during its three-year lifetime as the Pentagon struggled to keep pace with rising demand for M16s. By September 1967 alone the original 403,905 figure had more than doubled to 947,000 M16s, as the American military intervention in Vietnam deepened and there seemed no way to escape.80
As early as the winter of 1966 an embarrassed Pentagon was forced to admit that it had temporarily run short even of M14 rifles (it attributed the weapons deficit to “increased unit activations”) and had been obliged to give trainees M1s taken from depot stocks.81 Because M16s had still not been officially approved for general use in Vietnam, soldiers were being trained on M1s and M14s in the United States before picking up their M16s when they got to Vietnam. At the Marine Corps base at Camp Pendleton, California, it was reported, there were only between two hundred and four hundred M16s to go around, and each man who had been handed his orders for Vietnam received just a hundred rounds for practice.82Their unfamiliarity with the weapon, in combination with a ghastly error on the part of its manufacturers, led to calamitous incidents of jamming at critical moments.
One important aspect of the M16 of which recruits weren’t aware was its propensity to fouling and susceptibility to dirt. Eugene Stoner had originally used Du Pont IMR4475 “stick” powder (its granules looked like tiny tubes) in his Remington-made ammunition, but in 1964–65 it was replaced by ball powder made by Ordnance’s old friend Olin. At first glance ball powder was definitely a better bet: it burned longer and more slowly than IMR. On the downside, however, was that Stoner had originally designed the AR-15’s gas-port reloading system near the muzzle to suit IMR and all its parts were conceived to function rhythmically at a cyclic rate of between 750 and 800 rounds per minute. Ball powder, because its slow, steady burn achieved constant pressure along the barrel, retained a relatively higher pressure at the muzzle than did IMR, whose fast initial combustion resulted in higher peak chamber pressure. As a result of the switch to ball powder, the gas-port was therefore forced to work harder and the cyclic rate was pushed up to a thousand rounds per minute or more, thereby increasing the likelihood of feed and ejection failures. Worse, even as the elevated cyclic rate strained the capacity of the rifle’s mechanical components to keep synchronized, ball powder still burned when the gas-port was open, thereby searing and fouling the piece.83
With IMR, the M16 malfunctioned 3.2 times out of every thousand rounds; with ball powder, that figure sextupled to 18.5.84 Though some have suspected a conspiracy by Ordnance to sabotage the hated M16 with bad powder, this view does not stand up to prolonged scrutiny: expert military and civilian representatives of all four fighting services and the defense secretary’s office had approved the powder change. Their decision was the result more of confusion and hurry and carelessness than of anything else.85
The M16 jamming problem resulted in horrific, and all too often fatal, experiences. Specialist Galen Bungum remembered that at one point during a battle “I was crawling around looking for an M-16. I got my hands on one, and Specialist 5 Marlin T. Dorman said: ‘That doesn’t work; I’ll get you another one.’ Then he hollered: ‘That