Federal American Eagle Ammunition is loaded to NATO specifications, and even includes the green painted tip. This is the same ammunition currently being used by the US Military and is first run quality product. Headstamps will be marked with "LC" and the last two digits for the year of production. This ammunition is non-corrosive in boxer-primed, reloadable brass cases.
While the 5.56x45mm NATO will fit in a .223 Remington chamber, the 5.56 is a military round that runs at higher pressures than its .223 counterpart and is not recommended to be fired in a .223 Remington chamber.