In 1948, the U.S. Army established the Operations Research Office (ORO) to analytically study a number of problems associated with ground weapons in the nuclear era.
One of ORO's early projects was ALCLAD, a search for better infantry body armor. During this search, the ORO discovered just how little was known about how individuals were wounded in combat. ORO looked into several questions regarding the manner in which soldiers were struck by rifle projectiles and shell fragments, including:
- frequency and distribution of such hits
- the types of wounds incurred in combat and
- the average ranges at which wounds were inflicted
Answers to these questions were obtained by evaluating over three million casualty reports for World Wars I and II, as well as data from the Korean conflict.
ORO's investigations revealed that in the overall picture, aimed fire did not seem to have any more important role in creating casualties than randomly fired shots. Marksmanship was not as important as volume. Fire was seldom effectively used beyond 300 meters due to terrain (WWII, Korea) although sharpshooters in WWI frequently saw 1200m shots, and it discovered that most kills occur at 100 meters or less.
In 1955, American soldiers were sent into Vietnam with M14s. At first glance, this wasn't a bad idea until American soldiers fought the North Vietnamese's secret weapon: the AK-47. In comparison to the M14, the AK was lighter, faster, and controllable in fully automatic. This gave the North Vietnamese the upper hand over American troops. When the battle reports came in, the Army saw the problem bright and clear: the M14 wasn't holding up. They needed a new weapon and fast. So the United States Army Continental Army Command (CONARC) sponsored the development of a next generation .22 military rifle based on ORO's earlier findings.
They asked Winchester and Armalite to come up with designs. They needed the rifle to be:
- Lightweight (6 lbs loaded)
- Capable of Selective Fire (full and semi auto)
- Chambered In Lighter Caliber (.223 Remington)
- Large magazine (20 shot magazine)
- Lethal (penetrate a standard Army helmet at 500 meters rifle)
Here were the manufacturer's submitted rifles:
- Winchester - .224 Lightweight Military Rifle - patterned after M1 and M1 Carbine.
- Springfield Armory - an Ordnance Corps facility, was forbidden to enter its rifle by those opposed to small caliber concept, but it too had a .224 model based on the M14.
- Armalite AR-15 - A lightweight .22 Military rifle derived from the AR-10.
The Armalite Division of the Fairchild Engine and Airplane Corporation, Costa Mesa, CA was established in 1954 for the sole purpose of developing military firearms using the latest in plastics and non-ferrous materials. It's team of Eugene M. Stoner - key designer, Robert Fremont - prototype manufacturing supervisor, and L. James Sullivan - who oversaw drafting work had been they key developers of the AR-15.
Prior to the AR-15, Armalite had developed:
AR-1 - 7.62 NATO parasniper rifle, extremely lightweight, using Mauser-type bolt action; only prototypes built in 1954
AR-3 - 7.62 NATO self-loader using aluminum receiver, fiberglass stock, and multiple lug locking system similar to the one later incorporated into the AR-10
AR-5 - .22 Hornet survival rifle developed for US Air Force and officially designated the MA-1
AR-7 - .22 long rifle self-loader, receiver and barrel store in plastic stock. (1959-1960)
AR-9 - 12 gauge self-loading shotgun with aluminum barrel and receiver (5lbs) 1955
AR-10 - 7.62 NATO auto-loader, aluminum receivers, led to AR-15 design
The AR-15, designed around slightly enlarged version of the .222 case firing a 55gr projectile at 3300fps, and weighing in at 6.7lbs, took some of the best features from earlier designs:
- Locking system similar to Johnson Automatic Rifle
- Gas system from Swedish Ljungman AG42B
- In-line stock to help with manageability during auto fire
- Hinged upper/lower from FN-FAL
- Rear sight in carry handle like British EM2
- Ejector port cover from MP44
It had met all of CONARC requirements. It's lightweight, versatile, lethal, accurate - especially if equipped with an AR-15 optic, and reliable. In fact, when compared to the M14 rifle, the AR-15 was more powerful, soldiers could carry more ammunition (649 rounds vs 220 rounds), and was three times more reliable (as noted in during the tests).
The best part? The AR-15 production could be highly automated, making it inexpensive to manufacture. . It's 5.56mm cartridge fired a small 55gr bullet at nearly 3000fps, and it was accurate and effective to 350 yards. That small cartridge combined with the buffer system and inline stock made it far more controllable in automatic fire than the M14. In short, it was a perfect match. However, there was one hurdle Armalite had to first overcome: politics.
The Politics Surrounding The AR-15's Adoption.
The Army hesitated to adopt the AR-15.
They believed traditional larger caliber rifles with long-range accuracy were better for warfare. So the U.S. Army stayed with the M14, despite field tests clearly showing the AR-15 outperforming the M14 in all departments.
When the Air Force tested the AR-15 in 1960, they were impressed by its performance and ordered a whopping 8,500 rifles (along with 8,500,000 rounds of ammunition). In 1961, the U.S. Air Force requested an additional 80,000 AR-15s, however, the request was rejected. Why? Because General Maxwell Taylor (supporter of the M14) advised President Kennedy that having two different calibers within the military system could cause problems.
That's when William Godel, a senior at ARPA sent 10 AR-15s to South Vietnam for testing. The response? They loved it, requesting additional AR-15s to be sent. Despite the great deal of success, the U.S. Army STILL didn't want to adopt it.
At this point, the U.S. Secretary of Defense (Robert McNamara) had two conflicting views: the USAF and ARPA favoring the AR-15 while the Army favoring the M14. To help resolve the confliction, Cyrus Vance, secretary of the Army, ordered an investigation into why the AR-15 wasn't being adopted. The investigation found the tests were rigged in favor of the M14. Upon discovering this, the U.S. Army quickly adopted the AR-15 and renamed it to the M16.
The Military Adopts the M16
At first, the U.S. soldiers were getting beat by the enemy's AK-47, but when the soldiers were equipped with the new M16, the tide turned real quick. The North Vietnamese trembled. In fact, the M16 earned the reputation as "The Black Rifle" by the North Vietnamese in the war. The reason? The rifle was deadly. Matter of fact, the rifle was so deadly that the photographs of the gruesome wounds were classified well into the 1980s - more than 15 years AFTER the Vietnamese war ended.
Yet the M16 had its weaknesses. Specifically, the rifle would keep jamming. This cost the lives of countless soldiers. As one Marine recalled: "We left with 72 men in our platoon and came back with 19. Believe it or not, you know what killed most of us? Our own rifle. Practically every one of our dead was found with his (M16) torn down next to him where he had been trying to fix it".
This was due to the damp environment and increased carbon. As a result, the cartridge would get stuck in the chamber after firing. To resolve this problem, a new rifle was designed. The M16A1. It featured a chrome-plated chamber and bore to eliminate stuck cartridges and corrosion. In addition, the rifle came with a comic book-style manual outlining how to clean the rifle. As a result, jamming problems greatly diminished and the M16A1 rifle's reliability significantly improved. Shortly after, the AR-15 slowly reared its way to the civilian market.
Written by Edward Avila with an update by Richard Douglas in 2020.