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derbel_mcdillet writes:

in response to ReformBainbridge:

(This comment was removed by the site staff.)

I’m very familiar with the wounding effects of the M16. I performed tests at the US Army’s Wound Ballistics Laboratory in the early 1990’s.

When the M855A1bullet strikes and penetrates a human body it yaws. The stresses imparted on the bullet as it yaws through 180-degreesin soft tissues causes the bullet to disintegrate (fragment) into its three components – 1) steel tip, copper core slug, and guilding metal jacket.

The older M855 bullet, when fired from an M4 carbine, has an effective fragmentation range of about 70 yards. It was designed to be fired from a 20” barrel, and when fired from an M16A2 or M249 SAW (both of which have a 20” barrel), the effective fragmentation range is about 150 yards, give or take. The newer M855A1 extends the M4’s effective fragmentation range which allows it to inflict wounds of greater severity at greater ranges than the older M855.

M855A1 delivers more consistent terminal performance in the human body because of its construction. It consistently yaws and fragments at the cannelure after penetrating a consistent depth in human soft tissues. Whereas the earlier M855 and M193 bullets delivered inconsistent wounding effects due to varying degrees of fleet yaw (bullet wobble during flight). Factors that affect fleet yaw are the particular weapon from which the bullet is fired and manufacturing variations of the bullet. When a bullet wobbles it may hit the target at a few degrees yaw instead of 0 degrees point first. When it hits slightly sideways the bullet experiences greater penetration stresses earlier and fragments at a shallower penetration depth than a bullet that hits head-on at 0 degrees. If the bullet strikes head on at 0 degrees it may not yaw until it has, or, depending on the build of the person hit and/or the penetration path through the body, has almost, completely passed through the body. These variations in fleet yaw produce inconsistent wounding effects. M855A1 terminal performance is blind to fleet yaw. The bullet consistently yaws and fragments at a particular location along its penetration path regardless of whether or not it hits point forward or at a few degrees yaw.

Hydrostatic shock is not a term used by the professional wound ballistics community. The effect you refer to is temporary cavitation – which is, in essence, the tissue “splash” produced by a penetrating bullet.
