Evolution of the AR-15
In December of 1959, Colt acquired manufacturing and marketing rights to the AR-15. In 1962
Colt was able to get the Department of Defense's Advanced Research Project Agency (ARPA) to
test 1,000 weapons in its Vietnam-oriented Project Agile. An enthusiastic report led to more studies from the Department of Defense and the Department of the Army, and despite strong Army opposition, Defense Secretary McNamara ordered 85,000 M16's for Vietnam, and 19,000 for the Air Force.
However, early reports showed that the M16 was not living up to expectations. These reports,
presented to McNamara by the Ordnance Department, showed the M16 having reliability as well as
accuracy problems. These reports in turn praised the Ordnance Department's own M14. While the
M14 performed well, it was too heavy for the hot jungles of Southeast Asia, and its ammunition
also would not allow more than 50-100 rounds to be carried on patrols, severely limiting its
capabilities as an automatic weapon.
Further evaluation of the M14 and M16 was done by an independent agency. It concluded that M14
was not as bad as had been suggested by some, that the AR-15 itself was not as good as its
proponents had represented it to be. However, they did note that the AR-15 had greater
capability for improvement, and that its small size and weight made it a handier weapon in
Vietnam.
The M16 was issued w/o proper training and inadequate cleaning supplies. Combined with the humid
jungle of Southeast Asia, this caused problems and the rifle gained a bad reputation. Because
tolerances were tighter than in previous military arms, the M16 had to be kept extremely clean.
War correspondents filed reports where the M16 was jamming, and many were shown on the evening
news. It was reported that our soldiers were being killed by a faulty rifle.
This led to Congressional investigations which turned up two related problems. First, the
cleaning issue. As training was provided, supplies issued, and some redesign, M16 performed
more reliably. The second issue dealt with the use of ball propellants instead of
IMR propellants. Remington had developed the 5.56mm round using one type of powder, but the
specification was changed during military contract production to allow an alternate. This
powder caused more fouling and increased the rate of fire
M16A1
The replacement of the powder, combined with a new buffer to slow rate of fire, a chrome plated
chamber and barrel to improve rust resistance, a closed prong flash-hider, forward bolt assist,
new buttstock w/storage for cleaning kit, and introduction of a 30-shot magazine was adopted as
the M16A1 and performed well for the duration of the 60's and 70's. This rifle was also produced
by GM and Harington & Richardson during Vietnam era as well as other countries including the
Philippines
STATISTICS
United States Rifle, Caliber 5.56mm,
Date Adopted: 28 February 1967
Length: 986mm (38.80")
Weight, empty: 2.89kg (6.35 lbs.)
Caliber: 5.56mm Ball M193
Muzzle Velocity: 975mps (3200FPS)
M16A2
In the late 1970's, the Army re-examined it's rifle situation. Existing M16s were well worn,
and the current programs that were looking into a replacement for the M16 were not far enough
along. So in 1978, the M16 underwent a Product Improvement Program. The results were an
increased barrel diameter, and one whose rifling was changed from 1:12 to 1:7 to accommodate
the new round, developed by Belgium's Fabrique Nationale, the SS109. This round extended the
range of the rifle, and propelled a 62gr bullet with a steel core at over 3000 fps. The rear
sight was modified to allow more accurate adjustments of windage by hand, as well as for
elevation calibrated out to 800 meters. It incorporated a case deflector to prevent brass from
hitting left-handed firers, and new round handguards to replace the older triangular design.
Also, full-auto capability was replaced with a three-shot burst. This allowed for more
controlled firing, as well as greater accuracy as all three rounds are downrange before the
effects of recoil can impact their path. This new rifle was adopted as the M16A2
STATISTICS
United States Rifle, Caliber 5.56mm,
Date Adopted: 20 November 1983
Length: 1000mm (39.37")
Weight: 3.77kg (8.30 lbs.)
Caliber: 5.56mm NATO Ball M855
Muzzle Velocity: 945mps (3100FPS
M4
In 1994, the U.S. Army officially adopted its second carbine of the 20th century. Though
carbine versions of the M16 had been used all along (as the XM177 as well as the CAR-15),
demand for these was limited to select groups. With the increase in the use of Special
Operations forces during and after the Cold War, the demand for a shorter, lightweight weapon
was increased. The M4 was developed by Colt's Manufacturing Company, and is intended to be
used by Special Operations forces as well as other select members of the military. It is
designed to replace a variety of carbines and SMGs in the Army's arsenal, as well as to repeat
the accuracy and reliability of the M16A2. It uses a 14.5" barrel, and a four-position
telescoping stock while maintaining the ability to mount an M203 grenade launcher. In the
collapsed position, it measures under 30 inches, and weights just over 5 1/2 pounds, with an
effective range of 600 meters. The M4 is available with 3-shot bursts (M4) as well as full-auto
capabilities (M4A1). Both versions of the M4 are equipped with a Picatinny-Weaver Rail system
to replace the carry handle. This allows for a variety of sighting systems to be mounted atop
the receiver, from the standard handle with A2 sights to night-vision devices, scopes, and
lasers.
STATISTICS
United States Carbine, Caliber 5.56mm, M4
Date Adopted: 15 August 1994
Length(ext.):
Length(col.): 861mm (33.88")
780mm (30.69")
Weight: 3.32kg (7.30 lbs.)
Caliber: 5.56mm NATO Ball M855
Muzzle Velocity: 884mps (2900FPS)
