Some people feel that the 5.56 round has little stopping power at below 2500 FPS as the standard US issue “Green Tip” 62 grain M855 round may not yaw and break up in tissue below that. Some studies show that the M855 will not yaw and will simply drill a .22 caliber size hole with minimal energy transfer below this speed. This study shows that a 7.5″ barrel will have a muzzle velocity of around 2300 FPS, below the point where some say the M855 round will yaw and fragment.
