From Guns.com:

The move came in an open letter to company employees by Doug McMillon, president and chief executive officer of Walmart, which operates more than 5,000 store locations nationwide. Out, after selling through current stocks, is handgun ammunition and “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.”