Ordnance Notes -- by Bob Stoner GMCM (SW) Ret.

M16A1 5.56mm Rifles

A late-issue M16A1 as determined by the 30-round magazine and enclosed flash suppressor. (Photo: US Army)

The "Black Rifle" superseded the M14 rifle in United States service. The original AR-15 rifle (for Armalite Rifle Model 15) was a small caliber derivative of the Armalite 7.62mm AR-10 rifle that had been a competitor to the M14 prior to the latter's adoption in 1957. The AR-15 in .222 Remington came about as a response to USAF General Curtis LeMay's call for a modern rifle to replace the venerable M1 and M2 .30 carbines used for Air Force Security Police.

The AR-15 capitalized on the trail blazed by the AR-10. The rifle used aluminum for its upper and lower receivers to save weight. It used an aluminum magazine. Its butt stock, pistol grip, and hand guards were made of space-age plastics that were impervious to water, chemicals, and rot. It was the antithesis of the machined steel and wood technology represented by the M14.

Dr. Eugene Stoner, an employee of Armalite Division of Fairchild Aircraft, demonstrated his new rifle to LeMay at an informal shooting session using watermelons. The AR-15's effect was very explosive as compared to the .30 carbine hits on the melons, and LeMay was convinced: he had to have this rifle for his troops.

When the current Secretary of Defense Robert S. McNamara heard that LeMay wanted a new rifle, he had a fit. The Army was working on a wonder weapon called the "Special Purpose Individual Weapon -- SPIW" which was to replace the M14. Since its standardization in 1957, the M14 had gone through more than its share of teething problems. Springfield Armory was the overseer of the M14 into mass production. The first subcontractor, Winchester Repeating Arms, had quality control and production problems. The second subcontractor, Harrington & Richardson, had even more problems getting rifles out the door and to the users. The third subcontractor, Thompson-Ramo-Wooldridge (TRW, Inc.) hit the ground running with a new plant and solved many of the problems experienced by Springfield, Winchester, and H&R.

McNamara was not happy with the M14's tortured introduction into service. He was also unhappy with Springfield Armory. He bet on the SPIW as the new "wonder weapon" for DoD agencies. The SPIW fired 13-grain darts called "flechettes") and 30mm or 40mm grenades. McNamara didn't want to be saddled with an interim rifle in a caliber that was not DoD issue.

Program delays with the SPIW forced McNamara to reconsider his decision, especially in light of results coming back from "Project AGILE." Participant advisors in "Project AGILE" took the AR-15 (now in .223 Remington caliber) into battle in Southeast Asia. Results from the field were glowing, especially when captured VC documents warned to beware of troops with the "black rifle."

McNamara decided to do a "one time buy" of the AR-15 (now called the XM16) for the USAF and Army Green Berets, Rangers, and Paratroopers. He felt it was a one-time buy because the SPIW was just around the corner and it would replace both the M14 and the M16. Colt Firearms of Hartford, CT was designated the prime contractor for the new rifle. The rifle was Type Classified as M16 by DoD, and by mid-1965 users began receiving their first production rifles. (Three years later, when the Viet Nam War demands outstripped Colt's production, M16s were belatedly subcontracted to Harrington and Richardson (H&R) and General Motor's Hydradynamic Division.)

Thanks in part to marketing hype, over enthusiastic and exaggerated reports, and criminal bungling on the part of Army Weapons Command, the M16 began having teething problems in the field. Most of these problems were caused by the manner in which the M16 was selected for service and internal turf fights within the U.S. Army (the procuring agency).

Origins of the problems:: When the M16 went into production, there was no technical data package available for Colt's to build it. Consequently, tolerances tended to vary and accumulate which, in turn, affected reliability.

Someone at DoD got the idea that the M16 did not need cleaning after use. Part of this idea came from the kind of powder used by the AR-15 rifles. Eugene Stoner specified the use of DuPont IMR powders which were very clean-burning, but tended to erode barrels faster than the Army's ball powders. The final nail in the coffin came when the Army decided to save money by standardizing powders between the M14 and M16 rifles. The Army selected ball powder and this caused problems from the start.

First Problem. Ball powders of the day had a high percentage of calcium that was left behind after firing. This fouling tended to accumulate in and around the gas port, gas tube, and bolt carrier key of the rifle. Fouling build-up reduced the gas available to work the rifle's action and it failed to function. In some cases (especially the gas tube), the fouling could not be removed and the part had to be replaced.

Second Problem. The use of ball powders increased the pressures at the gas port. This led to an increase in the full automatic cyclic rate, which led to reduced part life. At one time, it was so bad that the Army issued a deviation to its acceptance specification that allowed Colt to test the rifle with IMR ammunition (to pass the cyclic rate test) in order to ship rifles.

Third Problem. Although the Army had specified the use of chrome plating in the chambers and bores of the M14 rifle and M60 machineguns since adoption, the M16 was exempted as an economy move. Chrome plating of the bolt and bolt carrier was also deleted to save money and unfounded fears that the plating might come off the plated parts and damage the aluminum receiver. The result was that the fouling caused by the ball powders became even harder to clean off. The heat and humidity of South East Asia (SEA) also caused the chambers and bores to become pitted by rust. Once a chamber became pitted, the brass cartridge case would stick in the barrel and the bolt's extractor would tear off the cartridge rim. A cartridge stuck in the barrel would render the M16 useless and this problem had gotten a lot of troops killed.

Fourth Problem. Because DoD thought the rifle required little or no maintenance, the M16 was the only rifle ever fielded that DID NOT have a cleaning kit issued with it. Soldiers could not clean the rifle if they wanted to because to cleaning materials had been procured for them! The un-cleaned rifles began to jam and troops began to die.

Other problems. Also noted in the field were problems with the 3-prong flash suppressor and the issued 20-round magazine. Some troops used the 3-prong M16 flash suppressor to break the wire bands on C-ration boxes. This bent the prongs of the suppressor to where the severity would deflect the bullet or blow the bullet up as it passed through the suppressor. Users also demanded a 30-round magazine to replace the 20-round that was current issue. This feature was to catch up to the M16s chief rival, the AK-47, which came standard with a 30-round magazine.

By 1968, almost all of the M16s teething problems had been solved and the rifle was reliable: bores and chambers were chromed; cleaning kits had been issued; a new enclosed flash suppressor was on the rifle; and training on the care and maintenance had been done with the troops; and a product-improved M16A1 was in the hands of the troops.

Meanwhile, Colt had marketed various derivatives of the M16 to the DoD. One was a heavy-barreled squad automatic rifle on a bipod for use similar to the old Browning Automatic Rifle or BAR. The AR-15HB was not successful. A belt-fed version of the AR-15 was not successful either. A shortened carbine version called the CAR-15 "Commando" by Colt was successful and was issued to the DoD as the XM177, XM177E1, and XM177E2. The CAR-15 had a telescoping butt stock; a special sound and flash suppressor; the E1 and E2 versions had the forward assist of the M16A1; the hand guards were shorter and round instead of triangular in cross-section; and the barrels came in 10.5-inch and 11.5-inch lengths (before the suppressor was added). The XM-series "Commando" lives on in the M4 carbine (current issue to Naval Special Warfare units).

The M16A1 soldiered into the 1970s as the standard rifle of DoD. User complaints resulted in a product improved rifle, the M16A2. The M16A2 was first adopted by the USMC in 1983. The new rifle cured several problems in the M16A1: the butt stock was lengthened; the butt stock added a storage area for cleaning equipment; the rears of the upper and lower receivers were strengthened; an improved front and rear sight were fitted; an empty case deflector was added (for left hand shooters); the ammunition was improved for better penetration (heavier bullet); a heavier barrel was issued that had a faster rifling twist rate to stabilize the new bullets; long, round cross-section hand guards became standard (no more right and left sections to match); a 3-shot burst control replaced the full automatic function; the front receiver hinge point was beefed-up; and the flash suppressor was redesigned to make it a compensator (to help hold the muzzle down in automatic fire). The M16A2 is now standard with all DoD agencies.

The M16A1 is 39 inches long and weighs 8.1 pounds. The 20-round magazine was standard and replaced by the 30-round. The M16A2 is 40.5 inches long and weighs 8.8 pounds. The 30-round magazine is standard.

© 2005 Bob Stoner R3