Walmart will halt sales of ammunition for handguns and some military-style rifles, the company announced Tuesday, calling the status quo on firearms in the United States "unacceptable."
Walmart also said it will direct consumers not to carry firearms into its stores, a practice that is legal in "open carry" states but which has sparked safety scares in recent weeks.
The moves, which were praised by gun control advocates and ridiculed by gun rights supporters, came a month after a deadly shooting at an El Paso, Texas store claimed 22 lives, a calamity that has been followed by subsequent attacks, including another shooting over the weekend in West Texas that left seven dead.
Chief executive Doug McMillon called on Congress and the White House to enact "common sense" measures, including stronger background checks for gun purchases, while signaling the retail giant still plans to sell sporting rifles.
"As we've seen before, these horrific events occur and then the spotlight fades. We should not allow that to happen," McMillon said in a statement.
"Congress and the administration should act."
The actions stop well short of the outright ban on gun sales that some gun control advocates called for but are still significant given Walmart's size and prominence in many communities in the United States and its influence in corporate America.
Later Tuesday, Kroger, the biggest US supermarket chain, called for strengthened background checks and announced it was "respectfully asking that customers no longer openly carry firearms into our stores, other than authorized law enforcement officers."
The world's biggest retailer, Arkansas-based Walmart has more than 4,700 stores across America, many in conservative regions where political opposition to gun control is strong.
The hashtag #boycottwalmart was trending Tuesday afternoon on Twitter and the move drew a strident response from the National Rifle Association.
"It is shameful to see Walmart succumb to the pressure of the anti-gun elites," the NRA said. "Lines at Walmart will soon be replaced by lines at other retailers who are more supportive of America's fundamental freedoms."
On the other side, Everytown for Gun Safety praised Walmart for a "significant step forward."
Several Democratic presidential candidates also praised Walmart, while calling for more action, drawing further distinction from US President Donald Trump who has backed off efforts to tighten background checks.
Democratic presidential candidate Beto O'Rourke, who previously represented El Paso in Congress, called Walmart's move a "step in the right direction," adding, "we can't rely on corporations to stop gun violence. We need universal background checks, we need red flag laws, and we need to buy back every single assault weapon."
Walmart expects the changes to lower its market share for ammunition from around 20 per cent to a range of six to nine percent.
The company will also no longer sell ammunition for short-barrel rifles, which can be used for hunting but also in military-style weapons.
The company will still sell long-barrel deer rifles and shotguns and much of the ammunition they use, leaving its stores "even more focused on the needs of hunting and sport shooting enthusiasts," McMillon said.
No more 'open carry'
Walmart also unveiled new policies restricting firearms in stores, citing a number of incidents in which shoppers have fled stores after members of the public brandished such weapons in "open carry" states.
In one well-publicized incident last month just days after the El Paso shooting, a man in Missouri was arrested after entering a Walmart wearing body armor and carrying a loaded military-style rifle.
"We believe the opportunity for someone to misinterpret a situation, even in open carry states, could lead to tragic results," McMillon said. "We hope that everyone will understand the circumstances that led to this new policy and will respect the concerns of their fellow shoppers and our associates."
The moves announced Tuesday followed earlier actions by Walmart to restrict access to some weapons, including a decision in 1993 to halt handgun sales in all states but Alaska and in 2015 to end sales of semiautomatic weapons of the sort used in mass shootings.
On Tuesday, Walmart said it was also ending sales of handguns in Alaska.
McMillon noted he is a gun owner himself, adding "we understand that heritage, our deeply rooted place in America and our influence as the world's largest retailer. And we understand the responsibility that comes with it."