5.56 55gr M193 Winchester 500rd Range PackHigh Volume 5. 56 NATO Range Loads Winchester M193 The Winchester 5. 56 NATO 55 Grain M193 is a military specification range load built for high volume AR 15 and MSR training. The M193 ball load is the original 5. 56 NATO military specification a 55 grain FMJ bullet at approximately 3,165 FPS that feeds reliably, cycles cleanly, and delivers consistent accuracy in any 5. 56 NATO or . 223 Rem chamber. The 500 round range pack format is the most cost