Firearms engineer Merle "Mike" Walker, who patented a wildly successful but controversial trigger mechanism for bolt-action rifles and proposed ways to make it safer, has died in a North Carolina hospice at age 101, his daughter told CNBC.
He died on March 6 following complications from hip replacement surgery.
Walker was featured in the 2010 documentary Remington Under Fire: A CNBC Investigation, which examined allegations of a pattern of deaths and serious injuries linked to Remington rifles with the so-called "Walker trigger." In each case, victims or their families claimed the guns fired without the trigger being pulled.
Patented in 1950, the mechanism is in some five million guns, primarily Remington's 700 Series—the world's most popular bolt-action rifle. Remington maintains the mechanism is safe, and that the accidents are the result of user error, improper maintenance, or modification by the customer.
(Read More: Inside Remington Rifle's Controversial Trigger)
In a 2010 interview with CNBC, Walker called his firing mechanism a "perfect trigger," prized by shooters for its accuracy and smooth operation. But he acknowledged that as early as 1946—with the gun still in the testing stage—he wrote a memo describing a "theoretical unsafe condition," which could render the gun's safety mechanism inoperable.
In the 2010 interview, Walker attributed the problem to "bad parts." But critics—including experts hired by plaintiffs' attorneys—blame a so-called "trigger connector," integral to Walker'sdesign, that is supposed to smooth the trigger's operation. They say the connector can become misaligned, allowing the gun to fire without pulling the trigger even when the safety is on. Remington disputed the theory, claiming its experts have never been able to duplicate the alleged defect on guns returned from the field.
Nonetheless, Mike Walker himself drew up plans to change his own design. In 1948, documents show, Walker proposed a modification that would lock the mechanism's internal parts in place while the safety is on, preventing the gun from firing. But Remington declined to implement the change.
"It had something to do with cost," Walker told CNBC in 2010.
A 1948 internal analysis obtained by CNBC put that cost at five and a half cents per gun.
As complaints and lawsuits mounted over the years, Remington repeatedly decided against a recall.
In 2010, Walker said he believed the company should find out how many guns are affected and let its customers know. "If I was there, I would advertise the fact that the rifles need repairing if the safety didn't work right."
Walker retired from Remington in 1975, but continued urging the company to make changes in his patented mechanism.
"Please don't bring out a new bolt action without a fool proof safety," he wrote in a 1982 memo.
In 2007, Remington introduced a new firing mechanism for the 700 Series, dubbed the "X-Mark Pro." Plaintiffs' experts said the mechanism included some of the changes Walker proposed in 1948, and a source close to the company said Walker's controversial "trigger connector" was removed because it had become the focus of so many lawsuits. But Remington continues to use the Walker mechanism in some models, including military versions of the 700 widely used by U.S. Army and Marine snipers.
Asked in 2010 whether he believed Remington put profits ahead of safety and human lives—a charge the company adamantly denied—Walker responded with a chuckle. "No, I don't think so," he said. "I think it was stupidity."
Following his retirement from Remington in 1975, Walker remained an active gun enthusiast, taking part in national bench rest shooting competitions at age 99, and working on guns in his garage workshop past his 101 birthday.
When CNBC visited that workshop at Walker's invitation in 2010, he proudly displayed his certificate of induction into the Remington Hall of Fame.
—By Scott Cohn; Follow him on Twitter @ScottCohnCNBC