The M16’s debut during the Vietnam War was supposed to usher in a new age of lightweight, high-speed firepower. But instead of being welcomed with open arms, the rifle was quickly plagued by a reputation for jamming, unreliability, and letting soldiers down in the worst moments. That reputation, however, only tells part of the story. The truth is far more complicated – and a lot more revealing about how rushed decisions and bureaucratic resistance can fail soldiers in combat.
A Rifle Born Outside the System
Before the M16, most U.S. military rifles were created by government armories. The M1 Garand, Springfield rifles, and others were all born in government-controlled facilities. But the M16 started life as the AR-15, a product developed by a private company, Armalite, led by designer Eugene Stoner. Armalite didn’t manufacture weapons at scale; they were innovators. So they sold the rights to Colt, a company with deep government ties and experience navigating the politics of defense contracts.
Colt’s Gamble and Air Force Enthusiasm
Colt took a risk on the AR-15, hoping it could be the next big military contract. Their first break came from the U.S. Air Force, particularly General Curtis LeMay, who saw the rifle’s potential after a now-famous watermelon demonstration. LeMay ordered the rifles for the Air Force, but the Army wasn’t convinced. They were stuck in the past, loyal to the heavy, traditional M14. Many within the Army saw the .223-caliber AR-15 as underpowered and too radical. It wasn’t made of steel and walnut. It was aluminum and plastic. That scared people.
An Unofficial Deployment
Despite the Army’s resistance, American advisors and Special Forces in Vietnam began using the rifle. The first formal battlefield use of the M16 came during the Battle of Ia Drang in 1965. Soldiers praised its handling in tight jungle quarters where the full-sized M14 was cumbersome. They especially appreciated its light weight and controllable fire rate. But the success was short-lived, and soon, things started to go very wrong.
The Real Villain: Ammunition Changes
One of the biggest problems came from a silent change in ammunition. The M16 and its 5.56mm cartridge were designed together as a system using a specific type of gunpowder – IMR extruded powder. But when the Army wanted to ramp up ammunition production, they switched to cheaper, more available ball powder from old World War II stockpiles. They didn’t consult Colt or Eugene Stoner.
That switch changed everything. Ball powder increased the cyclic rate – the speed at which the rifle fired and reloaded itself. This threw off the rifle’s internal timing, making it try to extract a spent casing before it was ready. This led to jammed bolts and ripped cartridges. Worst of all, soldiers didn’t know why their rifles were failing. They just knew they weren’t working when they were needed most.
Corrosion, Not Dirt
Another serious flaw wasn’t visible to the naked eye. The M16 barrels and chambers were not chrome-lined. This was a known standard at the time, especially for humid, wet environments like the Pacific. Without chrome plating, the steel chambers began to corrode. When brass casings expanded from heat, they stuck to the corroded chamber walls and refused to eject. Soldiers would pull the trigger and nothing would happen. Or worse, the rifle would jam during a firefight.
Cleaning didn’t fix it. That’s the kicker. Despite the myth that soldiers just needed to clean their rifles more often, the core issue was that even the cleanest chamber couldn’t function if it was pitted and rough. Chrome-lining became the fix, but it came too late for many.
The Forward Assist Debate
To try and solve the jamming issue, the Army added a forward assist – a device that lets you manually force the bolt closed. Eugene Stoner strongly opposed this. He believed if a round didn’t chamber naturally, you shouldn’t be jamming it in. The Air Force agreed and ordered M16s without forward assists. But the Army insisted. While it added a psychological sense of control, it could also push damaged rounds into the chamber, worsening the jam or even causing dangerous malfunctions.
This was a classic case of bureaucracy overriding engineering. The Army didn’t trust the design, and instead of addressing the real issues, corrosion and bad ammo, they added a band-aid feature that arguably caused more problems than it solved.
A Lack of Cleaning Kits and Training
Even when cleaning could help extend rifle performance, soldiers weren’t given the proper tools to do it. The Army didn’t issue 5.56mm cleaning kits at first, assuming the rifle was “self-cleaning.” That idea is laughable in hindsight. Soldiers had to ask families to send cleaning kits from sporting goods stores back home. No training, no lubricant, no proper brushes – nothing. Eventually, a full cleaning kit was designed and distributed, but by then, the M16’s reputation had taken serious damage.
Fixing the Broken
It wasn’t all bad news. Eventually, the military corrected the core issues. They chrome-lined the chambers and bores. They redesigned key components, including the bolt, firing pin, buffer system, and disconnector. They even standardized a new, stronger finish for the bolt carrier group. The result was the M16A1 – a truly improved rifle that worked reliably in the field.
By the late 1960s and early 1970s, malfunctions dropped sharply. Soldiers who received fully updated M16A1 rifles with proper ammunition and maintenance tools found it to be reliable, effective, and lightweight, just as it was originally intended.
A Rifle That Outlived Its Critics
Despite its rough start, the M16 family didn’t fade away. In fact, it did the opposite. Over the next five decades, it became one of the most produced and widely used rifles in the world. Special Forces loved it. Allied nations adopted it. And its civilian cousin, the AR-15, became the most popular rifle platform in the United States.
The M16 is proof that even a botched rollout can’t bury good engineering forever. What doomed it early on wasn’t poor design – it was poor execution, ignored warnings, and stubborn resistance to change.
Bureaucracy vs. Innovation
What stands out most in this story isn’t just the technical mishaps. It’s how internal politics and bureaucracy nearly ruined what could’ve been a flawless entry into modern warfare. The Ordnance Corps resisted the M16 not because it didn’t work, but because they didn’t invent it. Their refusal to prepare the rifle properly cost lives, slowed progress, and led to the eventual disbanding of the Ordnance Corps altogether.
If there’s a lesson here, it’s that innovation must be supported, not smothered, by leadership. The M16 survived not because of the system, but in spite of it.
A Flawed Launch, A Legendary Legacy
The M16’s early failures in Vietnam were very real. But they weren’t caused by the rifle itself. They were caused by bad ammunition, lack of support, missing equipment, and rushed deployment. Once those problems were addressed, the M16 went on to become one of the most successful military rifles of all time.
And maybe that’s the most important takeaway – sometimes the right tool can still fail if the system around it does. But when you fix the system, great tools prove their worth. The M16 is still here today, not because it was perfect from day one, but because it had the potential to be – and eventually, it lived up to that promise.
Raised in a small Arizona town, Kevin grew up surrounded by rugged desert landscapes and a family of hunters. His background in competitive shooting and firearms training has made him an authority on self-defense and gun safety. A certified firearms instructor, Kevin teaches others how to properly handle and maintain their weapons, whether for hunting, home defense, or survival situations. His writing focuses on responsible gun ownership, marksmanship, and the role of firearms in personal preparedness.