Muzzle Velocity and Caliber as a Function of Bodily Damage

Factual Questions
1

In a recent thread on U.S. Civil War injuries, someone mentioned that the dreaded Minie ball inflicted such grievous injuries because the bullet was so large and the muzzle velocity so low.

Since F = M x A, wouldn’t a low muzzle velocity cause less damage, all other things being equal? Yet, I consulted with a gun expert recently, who said, yes, rifled muskets inflicted terrible bodily damage because the low-muzzle velocity prevented the slug from exiting the body, causing it to bounce around and increase the injuries.

I understand what he was trying to say, but it didn’t make sense to me. It seems a bullet with much higher energy would cause more concussive (shockwave) damage to a combatant. Admittedly, F=MxA doesn’t take into consideration the shape of the musket ball or bullet–whether pointed or somewhat blunted.

Please clarify.

2

Minie balls didn’t just cause such damage because they were big and slow, but also (mainly?) because they were soft, and readily deformed, allowing more energy to be transfered to the victim, forming monsterous wounds. As for slow? I dunno… They had roughly the same muzzle velocity as a .45ACP round. Wound ballistics are not very simple, and frequently seem counter-intuitive.

Dr. Martin Fackler’s work is a good primer.

3

Okay, back up a second…

First, remember that we’re talking the Civil War here. No antiseptics, no quality medical care, knives and saws as surgical equipment, no blood-expanders, etc.

The Minie` ball, actually one of the first real widespread “bullets” as opposed to a mere ball- as in sphere-, was “deadlier” in that it had grooves called “driving bands”.

These grooves gathered and held all manner of residues- from the powder fouling from the rifle barrel, to fragments of the victim’s coat or shirt- itself not terribly clean most of the time- to dirts andresidues from being carried around in a leather beltpouch or coat pocket.

This resulted in more common contamination of the wound and subsequent infection that the medicine of the time was ill-equipped to treat or stop.

Plus, the Minie` projectile occasionally came in a flat-point version, which tends to transfer more of it’s energy to the target, which resulted in more of a “tearing” wound rather than a piercing wound.

4

Try this experiment, Country Squire… get a valuable tea set, a small table, and a tablecloth. Put the valuable tea set on the table cloth. Now pull the tablecloth out from underneath the valuable tea set.

Would you want to pull the tablecloth out fast, or so?

When a bullet impacts with a body and it’s travelling at a (relatively) slow velocity, it’s going to cause more tearing as it tries to pass through the body. A faster bullet will pass right through like the proverbial hot knife through butter.

Another way to think about it is removing a band-aid fast or slow… :smiley:

5

Bullet energy at impact has less to do with “potential lethality” than most people think. What really causes damage/death is not KE, “shock waves,” or heat (from the KE); it’s the tearing of vital organs and the shattering of bones by a moving projectile. Of course, deeper penetration = more damage, so velocity is somewhat important. But I really don’t believe that a bullet that exits a body causes less damage than one that resides within the body.

6

http://www.straightdope.com/classics/a1_203b.html

7

It’s a sad day when someone has to report that Cecil was wrong, but sometimes you’ve gotta do it.

My guess is that, during Cecil’s research, a self-proclaimed “firearms expert” told him about the importance of “hydrostatic shock,” and he duly referenced it. It sounds like a good theory, and has a snazzy scientific ring to it, but it doesn’t hold much water (pun intended) among true experts. Fact is, so-called “hydrostatic shock” contributes very little (if any) to the killing mechanism of a biological body being pierced by a bullet. As my post stated above, death due to being shot by a gun is primarily the result of the bullet physically tearing into the body, causing bleeding and/or damage to vital organs.

8

I knew I heard the term hydrostatic shock from somewhere. It’s from Sci-Fi book called “A MATTER FOR MEN” It’s book number 1 in a series called “The War Against The Chtorr”
Here is their definition:
“Hydrostatic shock. It’s what happens when a bullet hits flesh. It makes a shock wave. The cells are like water balloons. They rupture. That’s what kills you, not the hole.”

9

Physical disruption is a function of bullet KE being turned into work in the body. That conversion depends on placement (Muscle, organ, bone hits), bullet shape & design, deformation, fragmentation (if any), and available potential energy (KE). The more efficient bullets do a better job of turning these facors into perminant wound cavities.

Sometimes, as documented by Fackler, hydrostatic shock does play a part, such as when a high-vel bullet strikes a relatively solid organ, such as the liver. Then, the hydrostatic shock may produce temporary wound cavities of sufficient volume as to exceed the elastic strength of the organ tissue, resulting in greater than expected tissue disruption (tears). The issue is tremendously clouded by the disparity of data, research, individual reaction to a wound, the vast range of bullets types, callibers, energies, and the large number of places & angles a bullet might strike the victim.

Fackler, Hatcher, and Marshall all agree on this one point: Low energy bullets don’t kill reliably. The big issues revolve around whether it’s medium mass/High velocity, large mass/low velocity, or low mass/very high velocity thats most effective in converting a bullet’s KE into work.

Simply put, we’ve only a small glimpse into how bullets kill, while having a great deal of practical knowlege in creating bullets that kill quite reliably. Call it the down-side of empirical research.

To bring this back to the OP, the Minie Ball moves relatively slowly (as compared to modern bullets), and expands well, thus, it wastes relatively little energy on creating large temporary wound cavities, while putting most of it’s energy into creating large perminant wound cavities. The Minie Ball, should it strike bone, frequently pulverises the bone, creating many, many fragments, which the create additional tissue disruption as they fly about in the body. That’s one of the reasons a bone hit in a limb pretty much equaled an amputation, if you didn’t bleed out on the spot. Combine this with the animal fat-based lubricant, and grossly unsanitary coditions, and you’re talking about very serious killer.