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No, that wasn't an AR-15!

[Crews McCullogh has gently rebuked me for referring to the carbine carried by Special Forces troops in 1964 as the AR-15, a semi-automatic rifle based on a design by Eugene Stoner and manufactured by Colt's Manufacturing Company in Hartford. Instead, it seems, the civilian weapon had already been modified by the US military, which bought 104,000 automatic-fire variants as the M-16 for the US Air Force and the XM-16E1 for the Army and Marine Corps. There was a significant difference between them: the Air Force version had no "forward assist" -- a tang or protrusion on the bolt that enables a rifleman to clear a jam by pushing the bolt forward (to seat the cartridge) or pulling it back (to eject an empty shell). To judge by then-Captain McCullogh's memoir, it was the Air Force M16 that was acquired by Special Forces in early 1964. The captions are mine, and the photographs from Wikipedia Creative Commons. — Dan Ford]

by William "Crews" McCullogh

The original M-16 rifle was a United States Military, poorly designed, selective fire 5.56mm rifle with a 20 round magazine. It was not an attempted replication of Colts Armalite AR-15, an excellent semi-automatic rifle. Many books and publications about the Vietnam War repeatedly and mistakenly refer to the M-16 as an AR-15, resulting in degradation of a very reliable weapon. Appearance of the two weapons is very much the same. Both fire the same ammunition. One can readily identify an AR-15 from an M-16. The AR-15 is only a semiautomatic rifle. It is self loading and fires one round each time the trigger is pulled. In contrast, the M-16, also self loading, is selective fire, semi-automatic or full automatic. On full automatic it continues to fire as long as the trigger is held and you have ammunition. Another identifying feature: The AR-15 had a bolt assist lever. The M-16 had a hole in the bolt for your finger to be used as a bolt assist. This was the greatest blunder in the design of the M-16. Often, with your finger you could not retract the bolt nor force it forward to seat. If you were in a fire fight, and it happened, you were at the mercy of the enemy.

SF troops were the first Army troops to be issued the M-16. Teams rotated in and out of Vietnam leaving their M-16s for their replacement team. Most incoming SF troops did not know the difference between the M-16 and the AR-15, and assumed they had AR-15s, thinking the AR-15 was a selective firing rifle, semi-automatic or full automatic. I thought the same until I actually used an AR-15 and learned that it was only semi-automatic. Colt's patents expired in 1977. There are now many manufacturers and variations of the AR-15. It is a very popular rifle, sought by many. It always has been, and remains, a semi-automatic rifle.

There were constant complaints about the M-16 jamming. In most cases, it was caused by not keeping the weapon clean. I carried my M-16 for five months, on many patrols through all types of weather, where we made contact and engaged the enemy in fire fights. I fired tens of thousands of rounds through my M-16 and never once did it jam on me. How? A very simple process, I loaded only 17 rounds in the 20 round magazine, cleaned it often, did not oil it, and kept it dry. I will discuss the 20 round magazine later. Troops using the M-16 were trained on, and had used, the M-1 carbine, M-1 rifle, and the M-14 rifle, with all parts machined out of the same metal alloys. They would normally continue to operate, even when abused, not kept clean and properly cared for.

[The M-1 rifle was the fabulous .30 caliber Garand issued to American warfighters during the 1940s and 1950s. The M-14 was similar but fired the 7.62mm NATO cartridge, had a 20-round box magazine instead of 8-round clips inserted from above, and was capable of automatic fire. When first used in Vietnam, it proved hard to control at full automatic, so most M-14s delivered to the country were restricted to semi-automatic fire. -- DF]

Most troops expected the same results from the M-16, and simply did not keep their weapon clean. In many cases they paid a severe price. When you go into combat, you may have many good friends, that you defer to and treat respectfully. In combat, your personal weapon is your best friend, and if you expect to survive, you must give it lots of personal care and attention. Never just grab it up and run without thoroughly checking it over, making sure it is clean, properly assembled and ready for combat. In all my combat experiences I was never frightened, but I knew how well I cared for my weapon could make the difference as to whether I lived or died.

In Vietnam, U.S. Army troops, including Special Forces, were not issued AR-15s. The Air Commandos were issued AR-15s. In early 1964 Special Forces were the first Army troops to be issued the M-16 rifles. The following year, in May 1965, U.S. combat units began to arrive, the 3rd Marine Division, the 173rd Airborne Brigade, and others. Many of those troops were issued the M-16 for jungle warfare. Ask any of those conventional combat troops and they will readily tell you they fought with M-16 rifles and had problems. Prior to that, Special Forces standard arm was the M-2, selective firing, 30 caliber carbine, semi-automatic or full automatic. The carbine was short, light, and the ammo was light. I found it to be a reliable weapon in close combat.

My detachment, A-424, 12 men strong, arrived at Boun Beng December 17, 1963. By default, I assumed command of the Strike Force Battalion, approximately 1,000 Montagnard Troops. Supplies were flown into the Cheo Reo airstrip by U.S. Air Force, Air Commandos. When they brought supplies, they would buzz our camp, then land at the airstrip. We had some old WW II two and a half ton trucks. When we picked up our supplies, the flight crew would always come back to camp for a visit. We would take them to the team mess hall for coffee and snacks. They were sharp, with starched fatigues, Australian bush hats snapped up on the side, a snub nosed 38 caliber, pearl handled pistol in a breast holster. We readily bonded with them. They loved tribal souvenirs, Special Forces were not issued C rations at that time. [The Air Commandos] always brought C rations to trade for tribal cross bows, arrows, spears, loin clothes, etc. On one occasion, the pilot asked me if I would like to have an AR-15 rifle. I had heard much good about the AR-15 and readily accepted. He told me his room mate was recently shot down and killed, and had left his AR-15 in their room. He brought it on their next trip and kept me in ammo.

I had thought the AR-15 had full automatic selection and was greatly surprised to learn that it was only semi-automatic. It was an excellent semi-automatic rifle. I took it on a few patrols, then abandoned it for my full automatic M-2 Carbine. In firing a single shot from a rifle, the trigger must be pulled smoothly, not jerked or you will not hit your target. When attempting to fire rapidly with a semi-automatic rifle you are merely jerking the trigger and have very little accuracy. If you are any distance from the target you will miss every time. With a full automatic, you can aim, pull the trigger, then keep your sights on the target.

What happened to my AR-15? On May 1, 1964 Special Forces were moved from CIA control to MACV control. Our team was due to rotate back to Okinawa within a month. I received a directive from MACV concerning souvenir weapons. You must request permission six weeks prior to departure fully describing the weapon or weapons. They must all be of foreign origin. No weapons of U.S. origin. To enforce this, all SF gear will be inspected prior to departing Vietnam. I left the AR-15 at Boun Beng and never knew who inherited it.

In January 1964 we received a crate containing 12 XM-16 rifles, one for each team member. The X designated experimental. A memo instructed me to combat test them, report my findings, and make any recommended changes. Being a mechanical engineer, and having owned and operated rifles and shot guns since the age of nine, and had fired expert on almost every small arm in the US arsenal, I gave them a thorough examination. The first flaw I spotted was the lack of a bolt assist lever. Instead, there was a hole in the bolt for your finger. I knew if the bolt jammed that could be a serious problem. When there is a bolt assist lever, you can quickly jerk back hard on it, or pound forward with the butt of your hand. It takes much more time to put your finger in a hole, where you have very little leverage, than to jerk on or pound on a protruding lever.

early model M-16
Early model M-16 with duck-bill flash suppressor, 20-round magazine, triangular front hand-grip, and no forward assist lever. It was this model apparently that was supplied to Special Forces in 1964, probably by the CIA.

Upon our departure from Vietnam we left our M-16s for our replacement team. I personally informed them that they were XM-16, experimental rifles, that would give them problems if not properly cared for. I instructed them how to clean and care for them. Most reacted as if they were insulted, they knew how to clean a rifle, they had been doing it for years. Their team commander, in an arrogant manner, said to me, "Don't worry, we all know how to clean a rifle." To that, I said, "Men, they are all yours and I wish you well."

My final report on the XM-16 included four recommendations for change. They were all accepted and incorporated in the M-16A1 (Alteration 1), a much improved rifle. I received a commendation letter from the commanding general of Army Ordnance. Four years later, in 1969 the M-16A1 replaced the M-14 rifle to become the Military's standard service rifle. During that four year interim, 1964 - 1969, U.S. troops were unnecessarily, stuck with the XM-16 version. The U.S. Army has now, largely replaced the M-16A1 with the lighter M4 carbine, similar in appearance to the older versions of the M-16.

Following are my findings and recommendations. By mere observation I knew that the finger hole in the bolt was a major flaw. Prior to taking the weapon on patrol I thoroughly tested it on our firing range. I quickly learned that the bolt assembly had dissimilar metal parts. This meant trouble. I knew from my engineering studies in chemistry, physics, and metallurgy, when dissimilar metals (different alloys) are coupled together it creates electrolysis and corrosion, which is accelerated in moist conditions. This could be overcome by frequent cleaning and keeping the bolt assembly dry. To accomplish this, I carried a clean dry rag wrapped in plastic inside my fatigue jacket. It was not unusual for me to clean my weapon 3 or 4 times in a 24 hour period. If you were in base camp the weapon would continue to corrode and you must continue to clean it regularly to keep it ready for action. Many SF troops did not do that. The older Army rifles that they were familiar with could be cleaned, placed in a rifle rack for months and would still be ready for action.

My recommendation for correcting the first two flaws was to simply replace the bolt, with one that had an assist lever and no dissimilar metal parts. My thinking: These are the two flaws that are killing our troops. This can be done in short order, designed, manufactured and shipped to the troops. Removing and replacing the bolt was a quick and simple process. The same was true with the magazine. In WW II that would have happened, and quickly. In the Vietnam era both our military and our civilian government had become too bureaucratic. The bureaucrat says, it can't be done, even if it could, we can't do it now, we need a committee to thoroughly study the matter, and the wheels grind exceedingly slow. Almost four years later, they finally did it, the M-16A1. I have no doubt, there are many names on the Vietnam Memorial Wall that would not be there, today had my recommendation been expedited. We entered WW II and defeated all our enemies in less time than it took our military in Vietnam to correct two easily corrected problems that were killing our troops. I was thoroughly disgusted and still am when I think about it. I realize, that some manufacturer's profits were greatly enhanced by extending the process, and can only imagine how many extra millions that must have cost us.

The 20 round magazine was another design flaw. If you loaded 20 rounds, the magazine spring was forced down so tight that the bolt recoil spring could not force a round out of the magazine into the firing chamber. This frequently caused jamming, but was readily overcome by only loading 17 rounds. My recommendation was to replace it with a 30 round magazine with spring tension on the magazine and the bolt recoil spring properly calibrated.

The next design flaw was quickly discovered on my first combat patrol with the rifle. On patrols, if we expected imminent contact with the enemy, we carried our rifles pointed down ready for action. If we were fired on we could immediately hit the ground in a prone position, bringing our rifle into action. This action gave the enemy only a six inch target instead of a six foot target. The M-16 flash hider consisted of metal prongs that extended out about 2 inches from the end of the rifle barrel. When operating in underbrush, the only way keep your rifle barrel from having a bird nest on it, was to raise the barrel higher. My recommendation was, put a ring around the prongs. The M-16A1 was the first rifle to have that, it became known as a bird cage flash hider.

M-16A1
The M-16A2 adopted in the 1980s had a thinner and smoother front grip, 30-round magazine, improved flash suppressor, automatic fire limited to three-round bursts, and other tweaks. Altogether, M-16 variants have served American warfighters for more than fifty years, making it the longest-serving rifle in US military history.

When I began this I had not intended that it be a doctoral dissertation on the M-16 vis a vis AR-15 rifles. What was, was. Nothing can be changed. This is Vietnam trivia. What difference does it make as to what nomenclature a warrior thought his rifle was, that he lived or died by. It has absolutely no impact on our lives today. If you have bothered to read this, thanks, forgive me for intruding on your time. I was attempting to get it off my mind. But, not so, I am still pissed. This is but one of several things that told me in 1964 and 1965, we would lose that war. That is another much longer story.

William Crews McCulloch
Special Forces Detachment A-424 (aka McCulloch's Airborne Tigers)
December 1963-June 1964

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Posted June 2018. Text ©2018 by William McCullogh. Websites ©1997-2018 Daniel Ford. All rights reserved.