By Scott Cohn
CNBC Senior Correspondent

Millions of Americans hunt, but it is fair to say none of them expect what happened to Justen Yerger of Monroe, Louisiana.

“My life changed forever that day,” he recalls in an interview broadcast on April 11 on Rock Center with Brian Williams.

Yerger was 19 years old, fresh out of high school; the star kicker on his football team, with dreams of playing in college. But all that was about to change.

Yerger had returned to his truck after dove hunting alone near his home. He says he leaned his shotgun--a Remington Sportsman 12--against the wheel well, with the safety on. As he tossed his gear into the back, the gun fell over and went off.

He insists his hands were “nowhere near the trigger,” yet the gun fired anyway. His understanding had always been that a gun is not supposed to fire without the trigger being pulled.

“That’s what I’ve always known,” he says. “Especially when the safety is on.”

The next thing Yerger remembers was lying flat on his back on the ground. He'd been hit in his left leg and was bleeding badly.

“Seemed like every time my heart would beat, it looked like a water sprinkler.” 

A couple driving by saw Yerger and stopped to help. They rushed him to the emergency room at a nearby hospital.

“I was hit in my left leg - probably about three inches above my knee.”

Yerger’s ordeal was just beginning.

He spent three months in the hospital. Ultimately, it would take 13 surgeries, 128 units of blood and hundreds of thousands of dollars in medical bills for him to walk again.

He does not believe anything he did that day was wrong.

“I leaned my gun up. Gun's on safety,” he recalls. “There's not a doubt in my mind that I did not do anything wrong that day.”

Yerger sued Remington and the case eventually settled out of court. The terms of the agreement are confidential.

Now 34 years old with a family of his own and still suffering the effects of his injury, Yerger says his story is a cautionary tale for other gun users.

“They need to know that it can happen to anybody, anywhere, any time. I'm proof of it.”

No government agency can order a manufacturer to recall a defective gun. In fact, Congress specifically barred the Consumer Product Safety Commission from regulating firearms and ammunition, in keeping with the Second Amendment guarantee of the right to keep and bear arms. That means gun manufacturers police themselves.

But critics say Remington is shirking its responsibility when it comes to the firing mechanism used in some of the most popular long guns in America, including the shotgun owned by Justen Yerger.

Tom Butters, an engineer, marksman and a trained authority on firearms, has been paid as an expert in more than 100 claims involving reported malfunctions of Remington guns. He alleges Remington has been hiding a dangerous secret about the firing mechanism, which is known as the Common Fire Control or CFC. He says guns equipped with the CFC can go off without pulling the trigger, even with the safety on. And he claims the company has known about it for years.

“I would say it's been known to Remington ever since that first batch of guns went onto the market,” he told Rock Center.

That was in 1948, and since then, Remington has installed the CFC in some 20 million of its guns, and at least 20 different models. They include the 870 shotgun, which is widely used by law enforcement, the 742 semi-automatic rifle, and the Sportsman 12 that Justen Yerger owned.

The patented design of the CFC is unique to Remington. While the safety—the switch that's supposed to keep a gun from firing accidentally—locks the trigger in place, it doesn't block the internal parts from moving; specifically the hammer, the sear and the firing pin.

Butters says if those parts become disengaged, because of debris or even just bumping or dropping the gun, the result can be disastrous.

Butters and several other experts consulted by Rock Center say unlike some other gun makers that have changed their designs in response to similar issues, Remington has held firm.

Butters says Remington has done “virtually nothing” about the problem, and as a result, the owners of tens of millions of guns know nothing about it.

“And Remington does not want them to know about it,” Butters alleges, “because it will affect their market position.”

He claims Remington has essentially put profits over human lives.

“And I have made that allegation under oath on a number of occasions.”

Remington denies there is any problem with the CFC, and insists its guns are safe.

The company declined Rock Center’s requests for an on-camera interview, instead providing a written statement.

“The only defect rests with NBC’s inaccurate and biased reporting,” the statement says.

"(T)he fact remains that these guns are owned and used by tens of millions of waterfowl and upland hunters, competition shooters, law enforcement officers and military personnel—men and women who have relied on these firearms under the most extreme conditions over the last 60 years. These field, home and battlefield experienced users stand as a sophisticated and time-tested testament to the quality and reliability of these iconic firearms."

While the statement does not directly address the allegations of a design defect, Remington has confronted the issue head-on in numerous court cases. The company has consistently maintained its guns are safe, and that every incident can be attributed to modifications made by the user, poor maintenance, or careless handling.

The company has also challenged the credibility of Tom Butters, suggesting he is an expert for hire who has testified against a number of gun companies.

However, when Rock Center asked Remington to offer an expert of its own to counter Butters’ claims of an unsafe design, the company declined.

Butters says one of the most troubling aspects of the issue is that the guns can fire with the safety on, which is exactly what Russell Chaney of Pryor, Oklahoma says happened to him in 1984 while he was out on a boat, duck hunting with friends.

“I had my gun setting up on a bench. Kind of a seat,” he says.

He says as the gun slipped off the seat of the boat. As he tried to grab it, his hand slipped over the gun’s barrel. Just then, the butt of the gun hit the bottom of the boat. The gun went off, and blew off two of Chaney’s fingers.

A retired police officer, Chaney has been around guns his whole life and says he had never seen anything like it. Wondering how his gun could go off with the safety on, he sent it to an independent lab for testing.

“They duplicated the discharge, just like it happened, just like we did,” he says.

In its report, obtained by Rock Center, the Oklahoma forensic lab said it took the gun "with the safety off and no pressure on the trigger" and dropped it butt first.

"(T)he weapon discharged," the report says.

The test was then repeated with the safety on.

"(T)he weapon discharged again."

The report notes that in both tests, “the hammer had disengaged from the sear and had struck the firing pin, a condition which should only exist when the trigger is pulled."

So Chaney decided to write a letter to Remington.

“I was involved in a hunting accident because my gun goes off on safety when bumped on the butt,” he wrote. “Would Remington be interested in this gun for research?"

Chaney says he wrote the letter with one purpose in mind.

“I didn't want this to happen to somebody else.”

Remington agreed to look at the gun, but the letter the company sent back offered a much different conclusion than the independent lab.

"(T)he fire control, as received, showed no defective parts which could have caused the incident although the trigger was loose," Remington wrote, adding "(T)he firearm was repeatedly bounced on the butt from as high as thirty (30) inches without any discharge."

“I don't believe what they wrote to me in saying that it wouldn't go off,” Chaney says.

Asked if he thinks Remington was lying to him, Chaney says, “Well, I believe they probably were.”

Chaney decided not to sue Remington, but says he is troubled by the fact that he alerted them more than 25 years ago, yet incidents continued.

“Just kinda sad that these people are injured or killed,” he says, “after I know that they knew about the problem.”

Determining just how many others complained, though, is not easy. 

While a source close to the company insists Remington keeps records of every complaint, court testimony shows the company began destroying at least some records in the 1980s. But before that change, Remington had compiled a list of 119 complaints over a ten-year period.

Records or not, the problems continued. 

A five-month investigation by Rock Center has uncovered 125 incidents—including 75 injuries and seven deaths—all linked to alleged malfunctions of the Common Fire Control since 1973.

In Alaska, Paul Flynn was left quadriplegic when his Remington went off, and 15-year-old Philip Kensinger was shot in the face.

But many gun enthusiasts swear by their Remingtons. Jack Burch runs an Olympic training center outside Kerrville, Texas. He says Remington should alert the public if there's a problem. But over the past 11 years he says he has never seen any evidence the Remingtons are flawed.

“We see thousands of them come through here,” he says. “Kids shooting them, everybody.  Just not an issue.”

Asked why more users are not aware of the customer complaints, Burch says, “I'm suspecting because it's not as common as people would like to think it is.  It’s just not a pervasive problem that we see.  Not only in this range, but I talk to ranges all over the state.”

Remington does include all kinds of warnings with every gun it sells, including what the company calls "The Ten Commandments of Firearm Safety."

By the book, Russell Chaney and Justen Yerger violated at least two, including the first commandment, "always keep the muzzle pointed in a safe direction,” and the third, "don't rely on your gun's safety."

But critics say that only proves that even the most experienced shooter isn't perfect, and the design of the CFC should take that into account. Yet Remington has turned down a number of patented design changes, offered from inside and outside the company. They include a mechanism patented by Tom Butters and a colleague aimed at keeping the guns from going off unless the trigger is pulled.

In court cases, Remington has contended that Butters’ criticism of Remington’s fire control is motivated by a desire to make money from his alternative design, which Butters denies.

“Well, if I were all that interested in pushing the design I would have protected it,” Butters says. Instead, he allowed the patent to expire.

Remington contends the design change is unnecessary because the theory advanced by Butters and others that debris can compromise the CFC is implausible. The company maintains its engineers have never been able to duplicate the problem, and one of Remington’s paid consultants has called the debris theory “a mythical allegation.”

But documents from the 1950s paint a different picture.

In 1957, when a gun shop owner in Michigan wrote to complain about a customer's gun going off with the safety on, he mentioned "gunsmiths around here have told us this is a rather common occurrence and that the guns are unsafe."  

Remington responded the incident was "most unusual."

But just a year later, in a 1958 internal memo, Remington engineers identified the problem, that "might be aggravated by dirt or foreign matter in the fire control.”

And in 1985, when an insurance adjuster asked whether there were any problems with the model 1100 shotgun, Remington responded that it "had no problem," even though we found at the time of that letter, Remington had already faced a dozen lawsuits involving that model alone.

“As a professional engineer, my first canon of ethics reads, ‘I will hold the public safety paramount in each professional act,’" Tom Butters says. “I don't believe they did that.”