.223 is the civilian version of 5.56. There is a technical difference, but not a real practical difference. In terms of using the brass, it is essentially interchangeable. Unlike military 308 or 30-06 brass, in loading military 5.56 brass, reduced loads are not as critical because there isn't much difference in case wall thickness. LC, or Lake City Arsenal brass is good brass, but so is Remington, Winchester, and Lapua, if you can afford it.