Total wound channel comparisons

[tpd223]

Regardless of how much tissue a particular round crushes, it must still hit something vital to be effective.

In a recent street shooting we had a young lady was shot with a full power Foster style slug at very close range, although she lost about half of her left hamstring muscle from the hit, leaving an entrance wound over 2" and an exit that was about 8"X6" across, she didn't even know she was shot until after she ran away from the shooter and then started to notice she was bleeding.

Anyway, carry on.

[DBR]

BuckskinJoe:

What I posted is based on my reading Duncan MacPherson's 2005 book "Bullet Penetration".

There is a lot of math involved and nothing simple enough I can quote except the "shape factor". Bullets of differing shapes crush tissue more or less efficiently.

With respect to velocity: as the velocity increases above a threshold a bullet with a particular "shape factor" crushes more (or less) tissue per unit penetration for a given actual size and shape.

[NinjaMedic]

I need to educate myself more on BG and exactly how it responds to projectiles as a substance and maybe DocGKR has some thoughts however it would seem to me that a scientific volumetric analysis of the permanent cavity created would be a valuable indicator of a projectiles performance. It would seem that a internal displaced volume measurement or even 3D rendering of the BG post impact could yield valuable information much more precisely than (from my understanding) purely external measurements that are being performed. Especially now with "virtual autopsies" via CT/MRI becoming increasingly popular you could make similar measurements and images of actual GSW's and compare the data more precisely. Compare the actual 3d wound track with the predicted ones could allow us to more precisely understand how a projectile will perform inside of the body at various velocities, angles of attack, etc., along with how the internal structures influence the terminal ballistics. Maybe this is already being performed I dont know but I bet DocGKR or someone else would know and have a more informed opinion.

[panzerr]

Regardless of how much tissue a particular round crushes, it must still hit something vital to be effective.

In a recent street shooting we had a young lady was shot with a full power Foster style slug at very close range, although she lost about half of her left hamstring muscle from the hit, leaving an entrance wound over 2" and an exit that was about 8"X6" across, she didn't even know she was shot until after she ran away from the shooter and then started to notice she was bleeding.

Anyway, carry on.

She lost half her hamstring and managed to run away?

She may not have known she was shot due to shock, but I doubt she did much running with that much leg muscle gone.

[MK108]

...I guess that apart the larger mass of tissue crushed by the pellets of a single buckshot round compared to pistol ammunition....these pellets on penetrating the living target have much better chances to damage important structures and organs inside the body than a single projectile...

All the best
Andrea

[DrJSW]

I need to educate myself more on BG and exactly how it responds to projectiles as a substance and maybe DocGKR has some thoughts however it would seem to me that a scientific volumetric analysis of the permanent cavity created would be a valuable indicator of a projectiles performance. It would seem that a internal displaced volume measurement or even 3D rendering of the BG post impact could yield valuable information much more precisely than (from my understanding) purely external measurements that are being performed. Especially now with "virtual autopsies" via CT/MRI becoming increasingly popular you could make similar measurements and images of actual GSW's and compare the data more precisely. Compare the actual 3d wound track with the predicted ones could allow us to more precisely understand how a projectile will perform inside of the body at various velocities, angles of attack, etc., along with how the internal structures influence the terminal ballistics. Maybe this is already being performed I dont know but I bet DocGKR or someone else would know and have a more informed opinion.

I don't wish to stifle meaningful discourse, but this sort of discussion is akin to the medieval scholars' debates about how many angels can dance on the head of a pin.

A wound channel in the human body is not a simple cylinder, but rather a complex shape that, as others have pointed out and as Duncan Macpherson mathematically elucidated, is shaped by the meplat of the bullet (which, in expanding bullets, changes as it courses through tissue) and its velocity. Even if you were able to use an MRI to precisely measure the dimensions of a specific GSW tract in, say, a medical cadaver--and frankly, most MRI's aren't that precise for this sort of thing--you would get an entirely different wound profile if you varied the angle of incidence by 5 or 10 degrees, or changed the point of impact 2 centimeters to the left. The volume of the permanent cavity is also going to vary depending on what tissues it passes through, as some tissues are more elastic than others, and due to this elasticity, the actual vascular surface area exposed by the GSW will not bear a reliable relationship to the volume of the cavity.

Ballistic gelatin testing utilizes a homogeneous medium to determine how well ammunition performs when compared to all other types of ammunition. Ballistic gelatin wound channels do NOT approximate or predict the conformation of wound channels in heterogeneous tissue. As such, attempting to quantify the "wounding effectiveness" of one round vs another by arithmetical gymnastics or by pouring water into a gelatin wound cavity is unlikely to yield any meaningful information.

Incapacitation by pistol/shotgun GSW is, at bottom, a function of what specific anatomic structures are penetrated or perforated by the projectile(s), and the degree of tissue destruction caused thereby. As such the serious student of GSW's and incapacitation is better served by the study of human anatomy and physiology, learning the anatomic relationships of the vital structures in three dimensions, and simultaneously putting in some serious training time to master the application of his/her service handgun.

There are only two reliable and consistent means of incapacitation by gunshot wound: central nervous system destruction, and exsanguination (blood loss leading to catastrophic drop in blood pressure, which shuts down the CNS). In order to take out the CNS, you have to have accurate shot placement. In order to shut down the central portions of the circulatory system, you have to have accurate shot placement. If you have accurate shot placement and you are using good expanding ammunition, you will incapacitate your adversary whether your firearm is a 38 Special or a 45 ACP. The volume of the wound channel your bullet makes is of no consequence provided you put your bullets where the vital structures necessary to sustain life reside. DocGKR's sticky on service handgun calibers at the top of this forum addresses this from a ballistician's viewpoint. Perhaps you can consider this an answer from a trauma physician's and research physiologist's viewpoint.

There are other means of incapacitation by GSW such as psychological incapacitation, neural stunning, and musculoskeletal system destruction, but these are not reliable or consistent.

For a much more cogent and comprehensive discussion of these issues, you should re-read DocGKR's sticky, here:

https://www.m4carbine.net/showthread.php?t=34714

[DocGKR]

Dr. Williams is right on target, so to speak. Don't get bogged down in minutia. For example, please do not pour water or other material into the gel blocks--it does not offer any meaningful data and only serves to obfuscate the important parameters. Post mortem imaging is a useful overall adjunct, but not for exact calculations of wound volume--it does let us know that properly interpreted current lab testing offers a very good correlation with actual shooting incident results. From an end-user stand point, it is far more important to ensure you have a good mindset, choose a reliable weapon system, pick a quality load, get extensive training, then practice...a lot.

[tpd223]

"She lost half her hamstring and managed to run away?

She may not have known she was shot due to shock, but I doubt she did much running with that much leg muscle gone."

You can doubt all you want to, that's exactly what happened. She lost so little ability to walk/run that she had no idea anything was wrong until she noticed that she was bleeding all over the place.

She did have, being nice here, alot of thigh. She is rather a thick girl.



Docs,

Thanks for the reality check posts.

[DrJSW]

[QUOTE=tpd223;437415] She did have, being nice here, alot of thigh. She is rather a thick girl. QUOTE]

Nicely put.

An anatomical note: the "hamstrings" are actually two separate muscles, the semimembranosus and the semitendinosus. They function separately, with separate innervation and circulation. It would indeed be possible for an adrenalized person to run with one of the two muscles shot up.

[BuckskinJoe]

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In order to shut down the central portions of the circulatory system, you have to have accurate shot placement. If you have accurate shot placement and you are using good expanding ammunition, you will incapacitate your adversary whether your firearm is a 38 Special or a 45 ACP.
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Questions for DrJSW:

1) Is good expanding ammunition required for incapacitation, or is such possible with non-expanding round nose or FMJ bullets?

2) With accurate shot placement, is it possible with a typical, round nose .22 long rifle round to achieve incapacitation?

3) If incapacitation is NOT possible with a typical .22 long rifle bullet, regardless of shot placement, what, then, is the minimum required handgun cartridge and bullet to achieve incapacitation?

4) Since accurate shot placement is required for incapacitation, is there any reason to use a caliber/cartridge larger than the .22 long rifle (or the minimum required caliber/bullet that can cause incapacitation with accurate shot placement.)

5) Again, since accurate shot placement is required for incapacitation, is there any reason to fire more than one shot with the minimum required caliber/cartridge capable of incapacitation?