HornadyA(R) BLACK ammunition features versatile loads optimized for excellent performance. It's designed to fit, feed and function in a variety of platforms and delivers superior performance for a variety of applications. NOTE: While the 5.56x45mm NATO round will fit in a .223 Remington chamber, 5.56 NATO is a military round that runs at higher pressures, and is not recommended for use in .223 Remington chambers. Order today!