The old 1/14 twist with the 55gr FMJ of the original m16 is one reason they called it the meat axe. Increasing the twist to 1/12 with the a1 was *said* to reduce wounding capability as the bullet was more stable and less prone to yaw and fragment. I don't know if it is actually true (I kind of doubt it) but I just thought I would throw it out there since someone mentioned 'tumbling'.
