Be that as it may, the 5.56 usually does fragment, at the place where the bullet is crimped into the case. It does so after yawing at least 90 degrees, it often sheds its jacket too. The 5.45x39 (Russian) behaves similarly, although it's yaw cycle is shorter and thus it might yaw 360 degrees and more. See this site for more information on the terminal ballistics properties of various catridge/bullet combinations. The M193 and M855 FMJ 5.56X45 are the old and new military FMJ ammunition in question. One reason not to use for hunting, and use a SP type of bullet instead is that it ruins too much meat, depending on shot placement of course. The .222 Remington SP is an example of the latter type of hunting ammunition.