A demonstration of the AR-15 was made to
Curtis Lemay
in June 1960. He immediately ordered 8,500 for defense at Strategic Air Command airbases.
Colt Industries also approached the Advanced Research Projects Agency (ARPA), who bought
1000 rifles for use by South Vietnamese troops in the early summer of 1962. American special
operations units working with the South Vietnamese troops filed remarkable battlefield reports,
pressing for its immediate adoption.
U.S. Secretary of Defense
Robert McNamara
now had two conflicting views: the ARPA report favoring the AR-15 and
the Pentagon's position on the
M14
. Even President John F. 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's test report stated only the
M14 was
suitable for Army use, but Vance wondered about the impartiality of those conducting the tests. He ordered the
Army Inspector General to investigate the testing methods used, who reported that the testers showed undue favor
to the
M14.
McNamara ordered a halt to
M14
production in January 1964. In November, the Army ordered 85,000 XM16E1s for
experimental use, and the Air Force ordered another 19,000. Meanwhile the Army carried out another project,
the Small Arms Weapons Systems
(SAWS)
, on general infantry firearm needs in the immediate future. They highly
recommended the immediate adoption of the weapon, so much so that they started referring to it as the M16.
Later that year the Air Force officially accepted their first batch as the United States Rifle,
Caliber 5.56 mm, M16. The Air Force M16s were different from the Army XM16E1s, which had a forward
assist, as described below. The Air Force M16s were slightly modified AR-15s.
When the
M14
reached Vietnam with U.S. troops in 1965 its flaws were instantly recognized. It was far too
cumbersome and too heavy to use effectively in a close-quarters jungle environment, and the heavy ammunition meant
only small quantities were carried on patrol. The fully-automatic fire quickly demonstrated itself as useless,
as the British had suggested, and the rifles were eventually delivered locked in semi-automatic. In the end the
Army had spent a considerable amount of time and money switching from one semi-automatic weapon to another, and it
appeared this happened largely due to internal politics. In defense of the
M14
design, it was lighter and more reliable than the
M1 Garand
from which it evolved. While the M16 had the TCC and numerous changes to enhance its
reliability, the
M14
received no such attention. The Army chose to freeze the
M14's
design at an undeveloped stage.
Meanwhile the troops desperately tried to increase their own firepower in the face of the Viet Cong's Soviet-designed
AK-47
s. They improvised with any weapon they could find such as the pre-WWII Thompson submachine gun. The XM16E1 was
being introduced in increasing numbers, but quickly gained a bad reputation.
With the XM16E1 the Pentagon ordered a change in the cartridge's propellant from the clindrical Improved
Military Rifle (IMR) to the finer grained ball powder (the powder the rifle was originally designed around). The Pentagon
had previously changed the powder from the ball powder to the IMR in order to use up supplies of the IMR that were
left over from 30 calibre weapon systems. The IMR powder is a compressed load and therefore burns dirty. The change
back to the ball powder increased the cyclic rate of fire, increasing wear on parts, however, fouling was decreased.
Stoppages were generally due to a corroded chamber, poor maintenance, worn parts, or a combination of these. Though
cleaner, the ball powder only added to the increased wear. The solution was to redesign the buffer to slow down the
cyclic rate of fire at which point parts breakage returned to normal. As a testament to the original design, ball powder
is still used today in issue ammunition.
A forward assist was designed to close the bolt in case of a misfeed. Colt, the Air Force,
the Marine Corps and
Eugene Stoner all agreed
this device needlessly complicated the rifle and added about $4.50
to its procurement cost with no real benefit, but after another three years the Army ordered 840,000 of this version
on February 28th, 1967. The version became known as the
M16A1.
Colt had oversold the M16's reliability during testing, to the point where they claimed it never had to be cleaned.
The direct impingement gas operating system used a tube along the top of the barrel that vented gas back into a
'piston' formed behind the bolt and the recess in the bolt carrier. When combustion gases reached this area, they drove the bolt
carrier to the rear and then vented the excess gas out the ejection port and out between the gas key at the top
of the bolt carrier and the gas tube from the port in the barrel. Conventional designs keep the piston above
or below the barrel and vent excess gas at that point. The advantage of the Stoner system was that the 'piston'
formed by the bolt and bolt carrier operated in a direct line and on the same axis as the bore of the rifle.
This resulted in no adverse movement of the bore axis due to the movement of the bolt carrier assembly.
The adverse result of this design is that when the propellant gas is traveling down the tube, it cools and
condenses becoming solid carbon. This carbon builds up in the action of the gun quickly. The M16 therefore requires
frequent cleaning to remain reliable.
Making matters worse, troops were told the weapon required no cleaning because of its space age construction, and
had not been supplied with cleaning kits. In the field the guns started jamming all the time. Soldiers often
derisively referred to them as "toy guns" and used the catch phrase "You can tell it's Mattel" when one
malfunctioned. This later blossomed into an urban legend that the first M16s were actually in part, or completely,
manufactured by the toy giant.
The M16 debate once again took off, both in the Army and in Washington, DC. Stoner's latest design, a family of
weapons known as the
Stoner 63
, were sent to Vietnam for testing, while the SPIW flechette test weapon program was re-activated.
Luckily cooler heads prevailed. Cleaning kits were quickly produced, and a comic book was circulated among the
troops to demonstrate proper maintenance. The reliability problems diminished quickly, although the reputation
did not. This did not appear to be true for the North Vietnamese troops, however, who started to use the rifle
whenever one could be found.
Perhaps the most important change to the
M16A1 was the
introduction of chrome plating in the chamber, and some time later, the barrel as well. This improvement had been
suggested in the original SALVO tests, but was dismissed
as not cost-effective or practical. At the time, no reliable way had been devised to chrome-plate a .224" diameter
barrel. The true value of Chrome Plating is preventing corrosion in the Chamber. Being a nearly straight-walled
chamber, the slightest quantity of rust, corroded brass, sand, fouling, rust pitting, or even machining marks
increase friction exponentially. Soldiers in the field found that the first round nearly always fired but would
stick in the chamber. This is why the
AK-47
was designed with a tapered chamber.
Chrome lining not only prevents rust, but it also decreases friction. Fouling that does get into the chamber is
pressed into the side of the fired case and ejected along with it.
After its rocky start, the M16 has proven itself to be one of the more reliable combat rifles. By the end of 1967,
the troops, when asked, would only trade in their M16s for the XM177, a carbine version of the same weapon.
The lightweight round was likewise a matter of much debate in the rifle community. The "big round" concept refused
to die for many years, and calls for an increase in caliber continued into the 1980s. Much of the debate centered
on the Soviet Union's use of a larger
STG44
-style cartridge, the 7.62 x 39 mm, cut down from their wartime
7.62 x 54 mm "full power" design. The "official" debate ended for good when in the early 1970s the USSR
introduced their own small round, one even smaller than the M16 at only 5.45 x 39 mm.
Apparently SALVO had the right idea all along. The small vs large calibre military round debate however, still rages
amongst enthusiasts and military personnel. The large calibre proponents say that the small calibre round
doesn't have the knock down energy at longer ranges, the military's position is based upon combat studies and
states that most combat take place at under 100 meters and therefore the smaller calibre round has sufficient energy.
My opinion is that a well placed round, regardless the calibre, will
always do the job. Marksmanship is and always has been a key, but that seems to be left out of the recent debates.