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Gomez
01-31-09, 22:29
DocGKR,

I've seen this image and some others with a wound track profile overlaid on a human skull or torso and I am confused. My understanding is that the wound profile illustrates bullet performance in human leg muscle tissue or equivalent media [swine leg muscle or properly calibrated geletin].

It is my understanding that neither the skull nor the torso offer as much resistance as muscle tissue. Is this correct? Or do bullets, having penetrated the cranial vault, exhibit similar effects as when penetrating muscle tissue?

If so, it would seem that overlaying the wound profile onto the skull or torso presents an inaccurate depiction of bullet performance.

Sincerely, I am not attempting to be a smartass. This has been on my mind since I started seeing these images [yours and similar ones overlaying wound profiles on CT scans, I believe].

Sincerely,

Paul Gomez

Marcus L.
02-02-09, 08:42
You make a very good point. I don't think this overlay was meant to be accurate since duplicating the anatomy of the skull with gel isn't really possible. However, a fragmenting load will still begin is tumble and breakup in any hydrolic substance of the consistancy of body tissues within a similar penetration depth. So, this load should still have a high level of fragmentation in the cranial cavity and blow out the back of the skull. I've seen it with 5.56 OTM.

Gomez
02-27-09, 13:21
Marcus,

I appreciate the info. That basicly jibes with my assessment of the image. I just haven't seen any significant discussion or elucidation on the merit or purpose of these images from the guys posting them.

Thanks,

Gomez

DocGKR
02-27-09, 16:38
Gomez,

There have been LE trainers who have cautioned snipers not to make head shots unless they could be sure of hitting the "medulla oblongata" or "motor cortex"; the wound profile overlay illustrates the stupidity of that thinking by showing how the fragmentation pattern and temporary stretch effects of a rifle caliber projectile impacting the cranial vault will clearly cause profound damage to those structures with the likely result of blowing the back of the skull off and herniating the brain stem out the foramen magnum--think about the Zapruder film showing a non-expanding, non-fragmenting projectile hitting President Kennedy's head...

theJanitor
02-27-09, 17:24
i assume this applies to handgun cartridges too?

Gomez
02-27-09, 17:28
Gomez,

There have been LE trainers who have cautioned snipers not to make head shots unless they could be sure of hitting the "medulla oblongata" or "motor cortex"; the wound profile overlay illustrates the stupidity of that thinking by showing how the fragmentation pattern and temporary stretch effects of a rifle caliber projectile impacting the cranial vault will clearly cause profound damage to those structures with the likely result of blowing the back of the skull off and herniating the brain stem out the foramen magnum--think about the Zapruder film showing a non-expanding, non-fragmenting projectile hitting President Kennedy's head...


Thank you, sir.

DocGKR
02-27-09, 19:27
"i assume this applies to handgun cartridges too?"

No, it does not apply to typical service caliber and smaller handgun projectiles.

theJanitor
02-27-09, 19:44
at "typical" handgun distance, say 25 yards, which barrel length/cartridge combos that would accomplish instant incapacitation? i'm specifically interested in 45acp and 9mm

DocGKR
02-27-09, 19:55
Simple answer--NONE.

PA PATRIOT
02-27-09, 20:59
What would be the minimum pistol caliber which could completely penetrate a live human skull? My question is based on how small is too small caliber wise for off duty carry were a head shot may have to be taken on a active shooter. I wonder if my S&W model 37 2"bbl loaded with Safe Stop plated full wad-cutters can do the job at say 15yds?

DocGKR
02-28-09, 02:01
.380 ACP is inadequate; .38 Sp from a J-frame is the bare minimum I'd feel comfortable with and would prefer 9mm and up...

PA PATRIOT
02-28-09, 09:37
.380 ACP is inadequate; .38 Sp from a J-frame is the bare minimum I'd feel comfortable with and would prefer 9mm and up...

What would you suggest be the minimum velocity and mass out of that J-Frame? I'M still honing my ammunition choices for off duty carry guns and while I know no one load is perfect for every mission maybe there is one which can handle the bone of the skull or the sternum in the chest and still reach deep enough to get the job done. We always see what bullets do in bare or soft denim covered gel but I wonder how adding the fore mentioned obstacles would change the results. I always tended to look at wall board results when published then compare it to the bare shots to help judge a bullets possible performance when hitting skull or sternum. I maybe well off with the wall board/bare gel comparison but lacking any other source of information on the subject it was my best guess on the issue. I always wondered why the FBI never added those obstacles or a adequate substitution to their tests.

Sorry for another Greenhorn question gentleman.

DocGKR
02-28-09, 13:02
I am afraid there is no simple formula to calculate minimum effective projectile velocity and mass.

Thin flat bones like the sternum and ribs are no big deal; take a look at the work done by Kramer Powley and Dean Dahlstrom at the RCMP--they have shown that the addition of pig ribs into gel makes no significant difference in testing outcomes. On the other hand, orthopedic surgeon Dr. Ed Lane's tests of swine femurs embedded in gel blocks presented at the 1993 FBI Wound Ballistic Workshop demonstrated that thick long bones can pose problems for lighter handgun projectiles.

Skulls are another story. There is no way to adequately replicate the limitless intricate variations in skull anatomy prevalent in the world's population. Skulls present challenges to any service caliber handgun projectiles.

The wallboard test will not provide any of the information you desire--if you really want something for skulls, you would be better off looking at the auto windshield testing...