The decision by Walmart Inc. Tuesday to stop selling ammunition for automatic rifles came after it was personally impacted by a mass shooting, much the way Dick's Sporting Goods Inc. was when it banned the sales of assault-style rifles in August 2018.

Walmart announced a halt to all sales of short-barrel rifle ammunition that can be used with military-style automatic rifles, as well as handgun ammunition. In 2015, Walmart stopped selling semi-automatic rifles such as the AR-15. And in 2018, it stopped selling firearms and ammunition to people under the age of 21.

Walmart's decision comes in the wake two lethal shootings at Walmart stores this summer that took the lives of 24 civilians, including two Walmart employees at Southaven, Mississippi. A mass shooting at a Walmart in El Paso, Texas on Aug. 3 saw a lone gunman shoot dead 22 people with his AR-15 semi-automatic rifle.

Now banned from sales at Walmarts are short-barrel rifle ammunition such as the 5.56 mm rounds used in AR-15 type semi-automatic rifles and .223 caliber ammo. AR-15 weapons were used by the murderers to kill civilians at the El Paso Walmart and at Odessa, Texas on Aug. 31. The Odessa atrocity claimed the lives of seven people while wounding 22 others.

The .223 round made by Remington arms AR-15 type rifles and was developed in 1957 for the ArmaLite AR-15 issued to the U.S. Army. The official name for the .223 Remington in the U.S. Army is cartridge 5.56 x 45mm ball, M193.

The world's largest retailer and the private-sector employer will also cease all handgun sales in Alaska, completing its full withdrawal from the handguns category.

Walmart is also is asking customers at Walmart and Sam's Club to no longer openly carry firearms in stores in states where "open carry" is allowed unless they are authorized law enforcement officers.

Only five states -- California, Florida, Illinois, New York, and South Carolina, as well as the District of Columbia -- prohibit people from openly carrying handguns in public places. Open carry of handguns is currently legal in 45 states.

"We know these decisions will inconvenience some of our customers, and we hope they will understand," said Walmart CEO Doug McMillon in a memo to employees.

"As a company, we experienced two horrific events in one week, and we will never be the same. Our remaining assortment will be even more focused on the needs of hunting and sport shooting enthusiasts."

Since El Paso, McMillon said there have been multiple incidents at Walmarts "where individuals attempting to make a statement and test our response have entered our stores carrying weapons in a way that frightened or concerned our associates and customers."

McMillon also said there were also well-intentioned customers acting lawfully that inadvertently caused a store to be evacuated and local law enforcement to be called to respond.

"These incidents are concerning and we would like to avoid them, so we are respectfully requesting that customers no longer openly carry firearms into our stores or Sam's Clubs in states where "open carry" is permitted - unless they are authorized law enforcement officers," said McMillon.

He pointed out the opportunity exists for someone to misinterpret a situation, even in open carry states, and this might lead to tragic results

"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."

Of equal importance, McMillon said he sent letters to the White House and congressional leaders, asking for action on "common-sense measures." He calls on the federal government to "strengthen background checks and to remove weapons from those who have been determined to pose an imminent danger."

"Congress and the administration should act," demanded McMillon.

In February 2018, Dick's announced a halt to selling assault-style rifles and high-capacity magazines. It also raised the minimum age for gun purchases to 21.

The move came in the wake of the mass shooting at Marjory Stoneman Douglas High School in Parkland, Florida that left 17 dead.