The biggest of the big-box stores announced that they will end all sales of handgun ammunition in its stores.

Walmart said they will sell out current inventories of handgun ammunition and .223 and 5.56mm rifle ammunition and when they do they will no longer carry those types and calibers. They will focus ammunition on "hunting and sport shooting" ammunition. From the letter to employees on Walmart's website:

After selling through our current inventory commitments, we will discontinue sales of short-barrel rifle ammunition such as the .223 caliber and 5.56 caliber that, while commonly used in some hunting rifles, can also be used in large capacity clips on military-style weapons;
We will sell through and discontinue handgun ammunition; and
We will discontinue handgun sales in Alaska, marking our complete exit from handguns.

Hunting and sport shooting is done with handgun and 223/5.56 rifle ammunition as well. Here's a video of me doing so with a pistol two days ago.

They are also telling those who lawfully open carry handguns to not do so, unless they are law enforcement. Open carry is legal in South Dakota.

"...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."

But they are not banning the carry of concealed pistols.

"As it relates to concealed carry by customers with permits, there is no change to our policy or approach."

As someone who hunts and does sport shooting with pistol calibers and .223 rifle ammunition, this doesn't affect me in the least. I didn't buy ammunition at Walmart to begin with. I'll keep buying it at Gary's Gun Shop, Scheels, and Blue Collar Tactical or at local gun stores in the towns where I happen to be.