(CNN) Dick's Sporting Goods has destroyed $5 million of the chain's gun inventory, its CEO said.

After finding out that Dick's had sold the Parkland shooter a shotgun , CEO Edward Stack decided last year the company would no longer sell firearm to anyone under 21. Dick's announced it would destroy its inventory of weapons, rather than allow them to be sold by another retailer.

Since then, about $5 million of the chain's gun inventory has been turned into scrap metal, Stack said in an interview with CBS

"All this about, you know, how we were anti-Second Amendment, you know, 'we don't believe in the Constitution,' and none of that could be further from the truth," he said in the interview. "We just didn't want to sell the assault-style weapons that could inflict that kind of damage."

The shooting

Stack is a hunter and gun owner who believes strongly in the Second Amendment. The company, which his father started as a fish-and-tackle shop in 1948, has sold guns since long before Stack started working there in 1977.

But the mass shooting at Marjory Stoneman Douglas High School in Florida, on February 14, 2018, changed that. Seventeen people were killed in the attack.

Though the gun sold to the shooter was not the AR-15-style rifle used in the shooting, Stack said he couldn't stand being part of the narrative of mass shootings.

"We had a pit in our stomach," he told CNN soon after the shooting. "We did everything by the book that we were supposed to do, from a legal standpoint, we followed everything we were supposed to do. And somehow this kid was still able to buy a gun from us."



The decision

Stack told CBS the controversial decision cost his company about a quarter of a billion dollars in revenue.

Dick's is not the only national chain to be grappling with gun sales.