"We only had one son, and I lost him"

Richard Barber is a determined man. The Montana native's 9-year-old son Gus was killed when a Remington Model 700 rifle spontaneously discharged during a family hunting trip in 2000. Barber and his wife sued the rifle company, and Remington settled the case.

Since then, Barber has made it his mission to research Remington 700 "firing incident" cases and complaints, accumulating millions of internal Remington documents along the way. Why?

"To find the truth," he tells 60 Minutes correspondent Lesley Stahl in the clip above.

As Stahl reports this week on 60 Minutes, thousands of gun owners have complained that the Remington 700 — one of the most popular bolt-action rifles in American history — fired without anyone squeezing the trigger. The complaints involve both types of trigger mechanisms in the rifle: the older Walker trigger, and the newer X-Mark Pro, which was produced between 2006 and April 2014.

"If I only save one more life, I've done something that nobody else has even attempted."

In Barber's case, his Remington model had a Walker trigger mechanism. He says the day his son died, the shot that killed him fired as soon as the safety was released.

"We only had one son, and I lost him," says Barber, who planned to pass along his skills as a craftsman to Gus. "And everything I'd worked my entire life for up to that point was for nothing."

The Walker trigger remains in millions of rifles, and Remington has continued to receive complaints about it — nearly 2,000 in the last four years alone. Owners of guns with the Walker trigger brought a class-action lawsuit against Remington, claiming the company knowingly sold them a defective product.

Remington declined an interview with 60 Minutes, but in a statement the company said, "Remington stands behind the safety and reliability of its products and vehemently denies allegations that there is any design defect in the Walker trigger mechanism."

"They're saying the gun has been involved in accidents, but it's always the customer's fault," Barber says, telling Stahl that he is outraged by the images of missing limbs and lives he has seen in doing research about the Remington 700. He now maintains a website with a trove of Remington documents in an effort to educate the public about the potential danger.

"If I only save one more life," he says, "I've done something that nobody else has even attempted."

Editor's Note: Since this video was originally published in February, a judge approved the class-action settlement. While denying any design defect in the Walker, Remington is offering to replace the triggers for free.