Dick’s Sporting Goods not only took all assault rifles off its shelves — it even turned $5 million worth of the weapons into scrap metal, the retailer’s CEO revealed this week.

Ed Stack, who has been the CEO and chairman of the chain since 1984, told “CBS News Sunday” how he came to the controversial decision.

“I said, ‘You know what? If we really think these things should be off the street, then we need to destroy them,’ ” he said.

The billionaire businessman discusses the move — what he calls his “toughest business decision” — also in his book “It’s How We Play the Game: Build a Business. Take a Stand. Make a Difference,” which goes on sale Tuesday.

“Despite being a gun owner himself who’d grown up around firearms, Ed’s strategy included destroying the $5 million of assault-style-type rifles then in DICK’s inventor,” says a summary of the book on Amazon. “It was a profit-risking policy that would earn the outrage of some — even threats of harm — but turn Ed into a national hero.”

Dick’s was one of the biggest national sellers of firearms until 2012, when 20 students and six adults were slaughtered at Sandy Hook Elementary School in Newtown, Connecticut.

Afterward, Stack ordered all AR-15 rifles — similar to the one used by the gunman in the massacre — removed from every Dick’s Sporting Goods store nationwide.

“All we were going to do was just take it off the shelf and not say anything,” the CEO told CBS.

But when 17 people were slaughtered at Marjory Stoneman Douglas High School in Parkland, Florida, last year, that was the last straw for Stack.

“We found out that we sold this kid a shotgun,” Stack said. “That’s when I said, ‘We’re done.’

“Even though it wasn’t the gun he used, it could have been,” he said.

The retail giant announced that it would not sell any guns to anyone under age 21 going forward — and quietly reduced its remaining $5 million inventory of assaulting weapons into scrap metal, Stack said.

The National Rifle Association on Monday tweeted a Breitbart article about Stack’s decision to destroy the weapons, and the post drew a slew of mixed responses.

“Give that man a USA government cabinet position where he can do more like that,” one commenter said. “Every sane citizen of the USA meanwhile should make his shops their number 1 destination.”

But another wrote, “I stopped shopping there a long time ago…! (NRA-lifer).”