The move is said to be an attempt to tamp down the potential for theft of firearms if any of the company's stores are broken into amid ongoing social unrest across the country.
While the items are not being displayed at the stores, Walmart will continue to sell them in areas with large numbers of sportspersons and hunters.
The move comes in the wake of looting in Philadelphia after 27-year-old Walter Wallace was shot and killed by police on Monday.
Customers hell-bent on buying guns and/or ammo from select Walmart locations that typically sell such things will still be able to do so, per the Wall Street Journal's report on the move from Thursday evening, though they'll now have to make a special request for purchase.
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The decision comes after a fatal police shooting in Philadelphia triggered protests that saw some shops looted. Wallace's family said he had mental health problems.
The first time was back in June, following the death of George Floyd in Minneapolis.
"We have experienced some isolated incidents of unrest, and as we have done several times in recent years, we have removed our firearms and ammunition from store shelves for the safety of our employees and customers", said Kory Lundberg, a Walmart spokesman, in a statement.
The FBI database of firearms background checks shows 28 million checks initiated to date in 2020, more than the total for the entire year 2019.
Last year, Walmart stopped sales of some types of ammunition that can be used in assault-style weapons, and those used in handguns.