The History of the M-16
The original slab-side M16 rifle, which was the first AR-15 select-fire rifle adopted by the U.S. Military, was issued primarily to the Air Force in Vietnam in 1964. Note the lack of a forward-assist and case deflector behind the ejection port. It also has the old-style three-prong flash hider, a 20-round straight magazine, and the original triangular foregrip. The Air Force, Colt, and Eugene Stoner thought the forward-assist was an unnecessary expense. That’s why all other branches of the service were issued the XM16E1 variant in 1964, which includes the assist. Both were replaced by the M16A1.

The AR-15 was born during a time of turmoil and transition in the history of the U.S. military. During the 1950s, the Cold War was in full swing and we were entering an era of nuclear deterrence when future conflicts directly involving major powers seemed less likely than smaller-scale actions in proxy states. This was a radical change from the set-piece battles of the First and Second World Wars.

In the late 1940s, the Soviets had fielded the game-changing AK-47, ushering in an era of arming infantry with assault weapons on a mass scale. Lightweight, easy to wield, reliable, and packing a great deal of firepower, the AK-47 gave the Soviet Union, and its allies, a terrific advantage over its adversaries. The United States, meanwhile, adopted the M14 in 1957, a heavy-caliber firearm cut from the traditional “battle rifle” exemplified by the M1903 Springfield and M1 Garand—and it became obsolete the moment that it began rolling off the production line.

By the early 1960s this deficit could no longer be ignored. Even though the M14 represented a step backward (at least in its role as a general issue rifle; as a specialized weapon, it is an excellent firearm) the military had been exploring the concept of high-velocity small-caliber weapons since the 1950s.

This was the context in which the AR-15—later designated the M16 /XM16E1—came to the fore. On paper, it was an ideal choice. It fired a 55-grain 5.56mm bullet faster than 3,200 fps, and it also fulfilled the military’s requirements for penetration downrange.

Unfortunately, this rifle, the brainchild of Eugene Stoner and his colleagues at Armalite, was not ready for deployment. As C. J. Chivers phrased it in “The Gun,” his excellent history of the AK-47: “The early M-16 and its ammunition formed a combination not ready for war. They were a flawed pair emerging from a flawed development history. Though prone to malfunction, they were forced into the troops’ hands through a clash of wills and egos.”

A U.S. Marine with a modern M16A4 on a rooftop.
A U.S. Marine with a modern M16A4 on a rooftop. web photo

The results on the battlefield were catastrophic: These rifles jammed in battle and the soldiers that were carrying them died.

So why are the M16, its little brother the M4, and their civilian AR-15 counterparts still part of the landscape? Because, through the course of the ensuing decades, those flaws were worked out of the system, and the platform has now lived up to its potential, both on the battlefield and as a civilian sporting arm.

Improvements were made to the ammunition. The rifle’s barrel twist rates were optimized for various bullets. The chambers were properly chrome-lined. And, more recently, the incorporation of different sighting systems and accessories, along with the development of specialized uppers, barrels, stocks, and hand guards, has made the MSR America’s most versatile and popular rifle.

No matter the application—hunting, personal protection, competition, plinking—the AR-15 can be configured to get the job done.