From: gmk@falstaff.MAE.CWRU.EDU (Geoff Kotzar)
Subject: Re: computer simulation
Organization: Case Western Reserve University

In article <50655@mimsy.umd.edu> jheath@fieldofdreams.npirs.purdue.edu (Jim Heath) writes:
##From article <50615@mimsy.umd.edu>, by tnev2@isuvax.iastate.edu:
## In article <50532@mimsy.umd.edu>, edsr!kjs@uunet.uu.net (Kevin Sedota) writes:
## #Has anybody ever done a computer simulation of what happens to a bullet when
## #it hits a target? I was thinking of one of these slick computer graphics display

material deleted


#Isn't this akin to the LEAA's "Computer Man" from the late (?)
#70s.  There is a little history about it in the current Handguns
#(now Guns & Ammo was(?) Petersen's) in an article by Ed Sanow.
#That's April 1992.  I wonder what language that was written in
#and what computer(s) it ran on.


No, the problem of modeling the impact between a kinetic energy projectile
and some homo/non-homogeneous target material is not what the LEAA computer
man study tried to accomplish. Basically, the LEAA study used a model devel-
oped by the Ballistic Research Labs at the Aberdeen Proving Ground with a
slightly modified criterion of wounding "suitable" to the study of incapaci-
tation. Their studies required two live fire experiments: the first to deter-
mine the distribution of hits with the weapon system (handgun and cartridge)
subject to certain time constraints, and the second to determine the size and
shape of the Maximum Temporary Cavity (MTC) for each round of interest. The
results of these two series of tests were then overlaid by the computer onto
the computer man (CM). The CM was nothing more than a discretized 3-D model
of some average soldier/individual. The volume of the CM was broken down into
elements 25mm high by 5mm on a side. The long axis of each element was oriented
along the long axis of the body. Each element was assigned a value which was
supposedly its contribution to incapacitation when insulted by the passage of
the projectile. The insulting mechanism was also supposedly the MTC compressing
and displacing the volume elements. The program they wrote simply added up
something like 10,000 lines of action (wound tracts) whlie superimposing the
MTC on the ranked volume elements and then averaging.

The two serious flaws with the study that I have not seen discussed are the
ranks that were assigned to each element and the ranking mechanism. It would
take two long to go into each here, but briefly rankings are notoriously non-
linear and when thay are employed the statistics used to evaluate the results
should be of a non-parametric type. The LEAA treated their rankings as if they
actually were parametric values. Additionally, the values were assigned by a
group of trauma surgeons. The ability of surgeons of that type might be able
to accurately predict, say, fatality from the injured tissues but it is ques-
tionable whether they can predict a response that must occur within 5 seconds
by definition. The LEAA never bothered to validate the ability of the surgeons
to make such predictions; it can be done but it would require an extensive
double-blind type of study.

If you want to get some idea of the non-linearity and non-parametric nature of
assigned ranks, take any ten people you know and have them line up from shortest
to tallest and then count off. That is their rank. In general the assignments
will be non-linear when compared with their actual heights - which are BTW the
parametric values which should be used. If by some chance the ranks are linear
then just add one infant or one pro-basketball player and they will become non-
linear. This is exactly the problem with the CM study where the skin was 1 and
the spine was 10. Ten units of skin damaged equalled one unit of spine. I don't
think so!


geoff kotzar         gmk@falstaff.mae.cwru.edu

From: gmk@falstaff.tmc.edu (Geoff Kotzar)
Subject: Re: When the bullet finally stops...
Organization: Case Western Reserve University

In article <38940@mimsy.umd.edu> bercov@bevsun.bev.lbl.gov (John Bercovitz) writes:
#In article <38912@mimsy.umd.edu> oracle!bsloss@uunet.uu.net 
#(Benjamin Sloss) writes:
#
##  I will readily admit to knowing very little about guns, but as this question
##seems to pertain more to physics, let me give it a shot.  The problem here
##is one of energy transfer.  The more energy transfer, the more tissue damage.
#
#I used to think that the above is true but I'm no longer convinced.  I think
#it's important what that energy does.  Aha!  A reductio-ad-absurdum argument!
#(Now that I've confessed to being obdurate, I can use such.)  You get on an
#airplane and go up to cruising speed.  To do this, the seat back hits you 
#with 1.8*10^6 ft-lb of energy.  Most people survive.  OK, so that's not fair
#because bullets don't accelerate folks much.  

The time rate of transfer is very different for the two phenomena.

#Most of the energy
#probably goes into elastic deformation of tissues (and then the tissues
#"ring" for a while?).  

That is exactly what the contributors to the book "Wound Ballistics" editted
by Coates and Beyer discovered from their experiments on cat cadavers and
ballistic gelatin. These researchers were ones originally responsible for
demonstrating the suitability of ballistic gelatin as a substitute for live
or recently killed tissue. It was their formulation that was used by all of
the subsequent researchers until modified by Fackler. 


#What I'm trying to say is that there are lots of ways to dissipate energy and
#only some produce the desired effect.  If this were a precise science, we
#could even define a "bullet efficiency" equal to the energy required to do
#the destruction divided by the impact energy of the bullet.  On the same
#basis, a stiletto would have fantastic efficiency.
#
#        JHBercovitz@lbl.gov    (John Bercovitz)
#

With regard to efficiency, French and Callender in "Wound Balistics" gave a
factor of about 2.8 x 10**-3 inches**3 / ft-lb of energy for the amount of
tissue destroyed by the passage of a bullet - I am not sure of the exact
value of the mantissa, the book is at home. But this would corroborate the
original statement about increasing energy deposition resulting in increasing
tissue destruction and in a linear fashion. In the Journal of Trauma
Supplement from January of 1988 there is an article by Janson, Schantz and
Seeman called Scale Effects in Ballistic Wounding. They found a more
complicated relationship because the amount of tissue destroyed per unit of
energy deposited was also dependant on the amount of surrounding tissue. In
another earlier paper by Janzon and Seeman they found the amount of
devitalized tissue - determined by the amount of tissue that had to be
debrided - in the hind legs of pigs as a function of energy deposited to be
0.3 grams / Joule. Again a linear relationship. What this means for pistol
bullet injuries is not clear since thay all fall within the realm referred
to as "low velocity" and most of the serious work is centered around "high
velocity" injuries (1000 meters/second).  Also French and Callender examined
injuries cause by steel spheres to simplify the problem; Schantz and Seeman
examined injuries caused by M16 and Ak4 rifle bullets (military bullets).
With the possible exceptions of Fackler and Ragsdale there is very little
work being done on pistol bullet-tissue interaction and from what I have
seen it is not being done in a manner that will answer the more fundamental
questions.

Geoff Kotzar           gmk@falstaff.mae.cwru.edu

From: gmk@falstaff.tmc.edu (Geoff Kotzar)
Subject: Re: When the bullet finally stops...
Organization: Case Western Reserve University

In article <38844@mimsy.umd.edu> gregm@uunet.uu.net (Greg Mitchell) writes:
#In article <38816@mimsy.umd.edu> gmk@falstaff.tmc.edu (Geoff Kotzar) writes:
##
##You should remember that you are not really talking about cartridges but
##rather about the projectiles that are currently available for those cartridges.
##A bullet that will punch through 2 feet of a 450# black bear without coming
##apart is probably not going to perform spectacularly on a relatively fragile
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
##human being.
^^^^^^^^^^^^
##
##
##Geoff Kotzar                 gmk@falstaff.mae.cwru.edu

#Do you mean relatively to the projectile's total available destructive 
#capability or absolutely with regard to the particuliar target ?

What I mean here is that humans are not constructed very heavily and do not
provide a great deal of resistance to a projectile passing through. For
example we have no heavy coat of fur like all of the other animals that
would be considered big game, our skin (hide) is thin and does not offer
as much resistance to pentration as a common house cat's (anecdotal info
from WOUND BALLISTICS by Coates and Beyer Ed., pg 138), and we are as a
species not very heavily muscled and our muscle is not of the quality
found in other mammals. Fresh and fresh-frozen human cadavers we have
dissected in our lab have had muscles that looked like a piece of meat that
had been soaking in meat tenderizer for a day or so. Dissect a wild or even
many domestic animals and you would think you were dealing with a champion
weightlifter. The tensile properties of human muscle are also quite poor
compared to some very common animals: human muscle strengths range from
10-22 g/mm**2 while the "same" muscles from cats, dogs, rabbits, and domestic
fowl range from 8 to over 50 (from Yamada, STRENGTH of BIOLOGIC MATERIALS,
pp.94-96). BTW, the lowest values are for rabbits, which are not known for
being particularly tough in their own right.

#Please people don't flame me for this.  I have setup this scenaraio to
#illustrate my singular point.  I am not contesting what gun/caliber is the
#best choice for self defense.  What I am having trouble believing is a 
#statement made by more than one poster that a .44mag is not appreciabley
#more destructive to a human a .357mag .  Especialy in the case of non-vital
#area hits such as the pelvic region or the belly.  Please remember again
#that I am simply talking about destruction of the target, no other issues.
      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
#
#
#             Greg Mitchell             gregm@informix.com


Now with regard to DESTRUCTION of an animate target there is no contest
if you allow for certain reservations. The main reservation is the use of
projectiles which behave in similar manners. You should not compare an
armor piercing KTW bullet in .44 with a fast expanding bullet in .357. There
are two studies which indicate that the energy deposited in the soft tissues
is linearly related to the amount of tissue which is devitalized.

1) In "Wound Ballistics", the article by French and Callender reports that
   approximately 2.8 x 10**-3 inches**3 / ft-lb of energy deposited would
   be devitalized.

2) In "Muscle Devitalization in High Energy Missile Wounds, and Its
   Dependence on Energy Transfer" by Janzon and Seeman, J. Trauma, Vol. 25
   No.2, pp. 138-144, 1985, they report roughly 0.3 gm / Joule of energy.

Note: 1) In the first article steel spheres of various diameters were used
         at around 3000 fps.
      2) In the second, rifle bullets were used: M16 A1 and Ak 4 ammo. The
         significance here is that the data were generated with widely diff-
         ering projectile geometries.
      3) Devitalization was defined as the amount of tissue that had to be
         debrided by the clinician.
      4) None of this was performed with low velocity/low energy handgun
         rounds which includes essentially all of them. The break point
         for the low/high velocity classification is about 2000-2200 fps.
         The characteristics of the wounds produced are a function not only
         the amount of energy deposited but also the velocity at which the
         transfer occurs (the impact velocity).
      5) You can bet that the constants of proportionality will change for
         use with handgun ammo but for now we could still assume that things
         will remain linear at least over the narrow range of velocities and
         bullet diameters here. Hence, the .44 Mag with 60-70% greater energy
         than the .357 Mag should be capable of 60-70% greater damage provided
         all of the energy was transferred.

The field of would ballistics is terribly complicated and not well understood.
Comprehensive models do not exist for predicting the extent of the wounds
produced by projectiles as a function of the full range of velocities, pro-
jectile diameters, projectile terminal performance characteristics (which
includes deformation, yawing of elongated non-deforming projectiles, and
fragmentation) and finally the characteristics of the target tissue/simulant.

My apologies for the length of this and that it is a repetition of some info
previously posted, but in the field of wound ballistics rules of thumb that
won't ultimately let you down are very few.


Geoff Kotzar          gmk@falstaff.mae.cwru.edu

From: bercov@bevsun.bev.lbl.gov (John Bercovitz)
Subject: Re: When the bullet finally stops...
Organization: Lawrence Berkeley Laboratory

In article <39163@mimsy.umd.edu> gmk@falstaff.tmc.edu (Geoff Kotzar) writes:

#1) In "Wound Ballistics", the article by French and Callender reports that
#   approximately 2.8 x 10**-3 inches**3 / ft-lb of energy deposited would
#   be devitalized.

#2) In "Muscle Devitalization in High Energy Missile Wounds, and Its
#   Dependence on Energy Transfer" by Janzon and Seeman, J. Trauma, Vol. 25
#   No.2, pp. 138-144, 1985, they report roughly 0.3 gm / Joule of energy.

#Note: 1) In the first article steel spheres of various diameters were used
#         at around 3000 fps.
#      2) In the second, rifle bullets were used: M16 A1 and Ak 4 ammo. The
#         significance here is that the data were generated with widely diff-
#         ering projectile geometries.
#      3) Devitalization was defined as the amount of tissue that had to be
#         debrided by the clinician.

Forgive my tendency to calculate:
If we can assume that flesh has a density of around 1 gm/cc (actually 
slightly more),

            in^3    (2.54 cm)^3  .7376 ft-lb   1 gm
  2.8*10^-3 ----- * ---------- * ----------- * ----- = .034 gm/joule
            ft-lb     in^3          joule       cc

So the steel spheres do only about 10% of the destruction that the rifle
bullets do per unit of deposited energy at similar velocities.  Which kind 
of brings us around to what I was hinting at in an earlier post, namely that 
there's a lot more to tissue destruction than mere energy deposition.  One 
has to consider the mode of energy deposition also, I think.

#My apologies for the length of this and that it is a repetition of some info

No apologies needed; I'm sure I speak for many when I say that you've 
peaked our interest in a subject on which we have had few facts and only
personal speculation to guide us.  Thanks for the supplying the nitty 
gritty.

          JHBercovitz@lbl.gov    (John Bercovitz)

From: gmk@falstaff.tmc.edu (Geoff Kotzar)
Subject: Re: When the bullet finally stops...
Organization: Case Western Reserve University

In article <39171@mimsy.umd.edu> bercov@bevsun.bev.lbl.gov (John Bercovitz) writes:
#In article <39163@mimsy.umd.edu> gmk@falstaff.tmc.edu (Geoff Kotzar) writes:
#
##1) In "Wound Ballistics", the article by French and Callender reports that
##   approximately 2.8 x 10**-3 inches**3 / ft-lb of energy deposited would
##   be devitalized.
        ^^^^^^^^^^^

 ****** I am in error here. The correct statement should be "destroyed". *****
 ****** There is a problem with a slight difference in nomenclature      *****
 ****** between the two studies. French and Callender are refering to    *****
 ****** to the permanent wound tract here: the amount of tissue that is  *****
 ****** destroyed. The value for the constant of proportionality for     *****
 ****** tissue that is devitalized -called "the zone of extravasation"   *****
 ****** by French and Callender- and would have to be debrided is 30.1x  *****
 ****** 10^-3 inches^3/ft-lb of energy deposited. Since this value is    *****
 ****** the required factor of 10 greater the two studies come into very *****
 ****** close agreement for two very different projectile geometries. I  *****
 ****** am sorry for any confusion this may have caused you.             *****

#
##2) In "Muscle Devitalization in High Energy Missile Wounds, and Its
##   Dependence on Energy Transfer" by Janzon and Seeman, J. Trauma, Vol. 25
##   No.2, pp. 138-144, 1985, they report roughly 0.3 gm / Joule of energy.
#
##Note: 1) In the first article steel spheres of various diameters were used
##         at around 3000 fps.
##      2) In the second, rifle bullets were used: M16 A1 and Ak 4 ammo. The
##         significance here is that the data were generated with widely diff-
##         ering projectile geometries.
##      3) Devitalization was defined as the amount of tissue that had to be
##         debrided by the clinician.
#
#Forgive my tendency to calculate:
#If we can assume that flesh has a density of around 1 gm/cc (actually 
#slightly more),
#
#            in^3    (2.54 cm)^3  .7376 ft-lb   1 gm
#  2.8*10^-3 ----- * ---------- * ----------- * ----- = .034 gm/joule
#            ft-lb     in^3          joule       cc
#
#So the steel spheres do only about 10% of the destruction that the rifle
#bullets do per unit of deposited energy at similar velocities.  Which kind 
#of brings us around to what I was hinting at in an earlier post, namely that 
#there's a lot more to tissue destruction than mere energy deposition.  One 
#has to consider the mode of energy deposition also, I think.
#
#          JHBercovitz@lbl.gov    (John Bercovitz)
#
#

I really did not mean to set you up just so I could shoot holes in your
theory. Now if we knew the drag characteristics of theories, we could
then determine the amount of ego destroyed per unit of....

Thank for keeping me honest.

Geoff Kotzar         gmk@falstaff.mae.cwru.edu

From: gmk@falstaff.MAE.CWRU.EDU (Geoff Kotzar)
Subject: Re: Handgun Ammo opinions
Organization: Case Western Reserve University

In article <57789@mimsy.umd.edu> andy@sail.stanford.edu (Andy Freeman) writes:
#In article <57743@mimsy.umd.edu> webdw@mvutd.att.com (Bruce D Woods) writes:
##At the Second Chance bowling pin shoot last week, the Winchester
##reps fired a bunch of Black Talon ammo.  (various calibers) at
##a tub of water covered by a towel.  Then they allowed the folks
##to take a souvenier or two home.  They ARE IMPRESSIVE!  For example,
##the .45 ACP bullet ends up about half dollar size with six very
##jagged end sections.  Bits of towel were still attached.  Weight
##retention appears to be nearly 100%.  My guess is that the stopping
##power statistics will be obsolete once this (and similar) rounds
##are in common police & defense usage.
#
#How often do people shoot a tub of water covered by a towel to stop
#it?  (Performance in one media need not predict ANYTHING about
#performance in another.)
#

According to Ed Sanow in Handgun stopping power, there are some very good
simulants that are much easier to prepare than ballistic gelatin. Two that
provide a fairly good approximation to the performance of ballistic gelatin
relative to bullet expansion are water soaked newspapers and plain old water.
All three of these media will cause bullets to expand to roughly the same
diameters as living tissue. Straight water is supposed to be a less conser-
vative medium since it is somewhat more resistant than ballistic gelatin and
causes bullets to expand more than they do in BG and possibly in tissue but
only slightly so. The limitations to these two alternatives to BG become most
apparent when you want to "predict" stopping power using the Sanow Method.
Penetration depth is a meaningless concept for tubs of water (this can be
overcome though) and the permanent and temporary cavity estimation wind up
being distorted somewhat for both media. But for estimating expansion charac-
terisitics both alternatives work well and water is very reproducible, where
newspapers can dry out if the user is inattentive. Also, water soaked news
print provides a lot of useful comparative info with regard to pentration and
"wound channel" diameters. Note the word "comparative" above and the phrase
"wound channel". Here WC should not be construed to mean the actual region
of damaged tissue but only some measure related to the damaged tissue.

While I agree with the above statement that performance in one medium need
not be related to performance in another, the use of water to approximate
the effects of tissue on the bullet has been shown to be reasonably valid
and is a medium available to anyone anywhere.


geoff kotzar       gmk@falstaff.cwru.mae.edu

From: gmk@falstaff.MAE.CWRU.EDU (Geoff Kotzar)
Subject: Re: Hollowpoints illegal in N.J. ?
Organization: Case Western Reserve University

In article <1992Jul27.232134.21646@news.eng.convex.com> cash@convex.com (Peter Cash) writes:
#In article <1992Jul27.154046.10961@usenet.ins.cwru.edu> gmk@falstaff.MAE.CWRU.EDU (Geoff Kotzar) writes:
##In article <9207262135.AA01663@gtephx.com> forda@gtephx.UUCP (Andrew Ford @ AGCS, Phoenix, Arizona) writes:
#...
###That's about right: a hollowpoint is designed to expand more on impact and
###make a wider wound channel (bigger hole).  It is more likely to kill the
###person hit and less likely to go clean through the person and hit someone
###else.
#
##The above statements run counter to the collective observations of trauma
##surgeons in this country. In 1973 when high-velocity (relatively speaking)
##hollow-point handguns rounds were hitting the street -no pun intended- the
#...
##When surgeons experienced in treating gunshot injuries are asked to predict
##what kind of missile was used to produce a particular injury based on its
##appearance they cannot do it. Even estimating calibers used or magnum vs
##non-magnum is difficult if not impossible.
#
#This is really something of a bombshell: if you're right (and if I'm
#understanding you correctly), then it doesn't make much difference what
#caliber handgun you choose, or whether you use military ball or the latest
#super-duper-hollowpoint. The gun mags, the ammo companies, the gunmakers
#and their advertisers won't like this at all. Can you say more about
#this--particularly give a pointer to some references?
#
#I've always felt that gun writers tend to blow the differences between
#different types of handguns and ammunition out of proportion because that's
#how they make their living--but almost _no_ difference? Wow.


First I want to point out that there was a word left out of my first posting:
the word NOT in the initial paragraph. The paragraph that has been deleted
from the above by Peter. I have resubmitted it in corrected form. Basically it
said that the FBI's doctors could NOT detect a difference in the appearance
or severity of the wound whether produced by expanding or non-expanding
bullets.

My response was directed toward the statement that "hollow-point handgun loads
produce more severe wounds than loads using a non-expanding design bullet".
I am referring to morbidity and mortality, the amount of tissue destroyed and
the likelihood of death as a result. This is different than saying that the
response to the insult or injury is the same for both kinds of bullets. JHP's
clearly have demonstrated a superior track record in getting the attention of
the target animal (biped or quadruped). The problem crops up in that the
mechanism is not one of merely destroying more tissue. This is what DiMaio's
statement means. The wound tracts will be of different lengths as readers of
this newsgroup are aware but the diameters of the devitalized tissue are
not different enough to be detectable or to require a different form of
treatment.

My statement about the FBI's announcement was based on a piece published in
the FBI Law Enforcement Bulletin in 1973. I don't have the exact reference
here in my office. Nor do I presently have DiMaio's book here. I do however
have an article he published in the FBI LE Bulletin in December 1974. In it
he stated:

"The problem of public relations mat come up, especially with the use of
hollow-point ammunition. Myths have arisen about the terrible wounds caused
by hollow point pistol bullets. Such stories are complete nonsense. Pistol
bullets, even the new high velocity loadings, are in reality low velocity
projectiles. At autopsy, one cannot specifically tell from the extent of
the injury if an individual has been shot by a .38 Special 158 gr RN lead
bullet travelling at 789 ft/s or a 110 gr Norma at 1334 ft/s.

Similar stories concerning mutilating injuries have arisen about the magnum
calibers and the .45 Automatic. These cartridges and calibers again do not
cause particularly mutilating injuries. The wounds produced usually cannot
be differentiated from those of the traditional 158 gr RN .38 Spec. bullet."

An additional piece of evidence comes from a paper by Dziemiam, Mendelson,
and Lindley in the J. Trauma 1:341-353, 1961. The paper is entitled "Compar-
ison of the Wounding Characteristics of Some Commonly Encountered Bullets".
This was a study that examined wounds in living tissue (goats) and "wound
tracts" in 10% gelatin. In Figure-4, there are shown some entrance and exit
wounds from the goats. The cartridges were: .22 LR, .32 S&W, .32 ACP,
.38 S&W, .38 ACP, .45 ACP and 7.62x51mm. There is a difference between
the .22 LR and the .38's, but the .38S&W wounds look like the .32 ACP. And
the .38 ACP is indistinguishable from the .45 ACP. The only round that
was identifiable was the NATO rifle round as you might expect. And then
only if you examined the exit wound and ignored the entrance. The gelatin
wound tracts showed more of the same. And while these were all non-expanding
bullets remember that the .45 is a "pre-expanded .38".

One more piece of anecdotal data. Remember how the FBI in their latest study
and Ed Sanow estimated the permanent cavity (or permanent crush cavity). If
the damage done by direct contact of the bullets passing by produced markedly
different amounts of damage as a function of their construction, then the PC
should have been directly MEASURABLE with a set of calipers. Rather, it was
CALCULATED based on the expanded diameter of the bullet and the depth of
penetration.

So in closing, as long as you talk about bullets of conventional construction
as opposed to Glasers and PMC tubular bullets, the APPEARANCE of the wounds
produced by HANDGUNS, at handgun velocities much less than 2000 fps, are not
strongly influenced by bullet diameter or construction (meaning here expanding
versus non-expanding). Just why there is a difference in the reaction of the
animal being hit due to the differences in bullet construction is not clear.
But I think you must keep in mind that you are talking about two different
things: tissue distruction and physiological reaction.

geoff kotzar        gmk@falstaff.mae.cwru.edu

From: gmk@falstaff.MAE.CWRU.EDU (Geoff Kotzar)
Subject: Re:HP's Illegal in N.J.? ***CORRECTION***
Organization: Case Western Reserve University

In article <9207262135.AA01663@gtephx.com> forda@gtephx.UUCP (Andrew Ford @ AGCS, Phoenix, Arizona) writes:
#
#That's about right: a hollowpoint is designed to expand more on impact and
#make a wider wound channel (bigger hole).  It is more likely to kill the
#person hit and less likely to go clean through the person and hit someone
#else.


The above statements run counter to the collective observations of trauma
surgeons in this country. In 1973 when high-velocity (relatively speaking)
hollow-point handguns rounds were hitting the street -no pun intended- the
*** FBI released a survey stating that trauma surgeons could distinguish a
wound ***

THIS LINE SHOULD READ:
FBI released a survey stating that trauma surgeons could NOT distinguish a
wound

from an expanding bullet (hollow-point) from one produced by its non-expanding
counterpart. After twenty additional years development and experience, that
same observation was made by Dr. Vincent DiMaio of the Southwest Forensic
Institute in his book "Gunshot Wounds" that was published by Elsevier Scien-
tific Publishers in 1989, I think. Correction: Southwest Institute of Forensic
Sciences.

When surgeons experienced in treating gunshot injuries are asked to predict
what kind of missile was used to produce a particular injury based on its
appearance they cannot do it. Even estimating calibers used or magnum vs
non-magnum is difficult if not impossible.

The medical literature tends to break gunshot injuries down into two fairly
broad groups based upon striking velocity; essentially rifle versus hadngun.
This assumes of course that we do not include the exotic handguns. The break
point is roughly 2000 fps but it depends somewhat on bullet design. The
difference in tissue reaction between expanding and solid rifle bullets is
much much greater than between expanding and non-expanding pistol bullets.
The point here is that bullet construction is a more important factor in
determining tissue destroyed when a rifle was used than when a pistol was
used.

As far as mortality is concerned, where you are hit and how long it takes
before treatment is initiated appear more important than what caliber
handgun or what bullet design was used. However, I have no quantitative
info in my files on mortality as a function of handgun bullet design so
I am less certain about the mortality issue than about the morbidity issue.


geoff kotzar             gmk@falstaff.mae.cwru.edu

From: gmk@falstaff.MAE.CWRU.EDU (Geoff Kotzar)
Subject: Re: FN P90 5.7x28mm "PDW"
Organization: Case Western Reserve University

In article <53936@mimsy.umd.edu> skrone@cbnewsb.cb.att.com (stuart.krone)
writes:
#In article <53813@mimsy.umd.edu> bercov@bevsun.bev.lbl.gov (John Bercovitz)
 writes:
##In article <53677@mimsy.umd.edu> reb@amc.com (Bob Brunjes) writes:
##
###It appears that whena bullet passes through tissue at velocities greater
###that the speed of sound _in meat_, wondrous and destructive things
###happen.  "Tumbling" isn't necessary to describe the damage.
##
##The speed of sound in flesh is around 5000 fps.  Not many bullets go that
##speed.
##

#Are you sure about that? The human body is mostly water and if I recall
#correctly the speed of sound in water is about 3000 fps.
#I think the effect you are refering to is hydrostatic shock.
##John Bercovitz     (JHBercovitz@lbl.gov)


I am afraid to report that you recall incorrectly. According to the book
"Wound Ballistics" by Coates and Beyer, they provide the following: "The
velocity of the shock wave in tissue is approximately the same as in water,
4800 fps.", pg 212. Note that this text was printed in 1962 and since then
there have probably been additional studies to estimate the velocity of
sound in tissue somewhat more accurately. But I would not expect the value
to differ from that above by more than about 5%. 5000 fps is a pretty good
estimate.


geoff kotzar


From: gmk@falstaff.MAE.CWRU.EDU (Geoff Kotzar)
Subject: Re: "Killer" falling bullets?
Organization: /etc/organization

In article <34lpq8$ig5@selway.umt.edu> uncia@selway.umt.edu (James F Johnson) writes:
#In article <34kuqg$okj@xring.cs.umd.edu>,
#Martin Kruse <martinkruse@delphi.com> wrote:
#
##I dont think you need 300fps to break skin.
#
#Seems to me that sectional density would be a better predictor of
#penetrating power than simply velocity.  A ping-pong ball doing 600 fps
#probably won't go thru you, but a 40' long 1/4" steel rod traveling at
#at 100 fps would probably kebab the average family.
#

One of the early, if not the original source, of that information was
"Wound Ballistics" by Coates and Bayer. It was published by the Office
of the Surgeon General. (We have come such a long way haven't we.) Date
of publication was 1962. I got very lucky when I was dong some background
searches and called the Surgeon General's office. They had a few copies
left lying around and sent me one free. But that was back in the late 70's
or early 80's.

On pages 138 and 139, they discuss the issue of skin penetration. They used
1/8 inch steel spheres weighing 2 grains. The target material was human skin
and the threshold velocity was 170 fps. When they substituted lead spheres
weighing 7 grains they did not achieve penetration at 161 fps. They also
reported that a 150 grain bullet would require from 125 to 150 fps to achieve
penetration. As near as I can tell this is for skin stretched on a frame but
without any backing tissue.

Martin Fackler also commented on this issue in one of the IBWA reports. He
noted that the actual velocity is a function of where the skin comes from
on the body. Skin from the back is thicker than from the front of the body
and therefore more resistant to penetration.

Also, there can be an effect due to any underlying tissue. IE, skin at the
entrance site need not yield at the same value as skin at the exit site
even though both sites might be functionally equvalent. Skin at the exit
site is free to pull away from the connective tissue and this can result
in the forces being distributed elastically over a larger region. This
may well be truer for animals than for humans since our skin is pretty
well tethered to the underlying tissue.

Vincent DiMaio also conducted some tests on skin penetration and commented
on them in his book Gunshot Wounds on pages 213-214. He as well presented
a summary of some earlier studies on skin penetration by others. In 1907,
Jounee found that missles with velocities in the range of 265 to 660 fps
would not penetrate the skin of a horse but would penetrate to a depth of
20 cm into the underlying muscle if the skin was frst removed. With human
cadavers he found that 11.25mm diameter lead spheres (8.5 gram) needed 230
fps to perforate the skin and enter the muscle beneath. In 1974 Mattoo found
that 8.5mm diameter spheres weighing 8.5 grams required 234 fps to perforate
the skin and enter the underlying tissues.

DiMaio tested airgun pellets and .38 RN lead bullets (113gr). He found that
.177 pellets (8.25 gr) requred 330 fps to perforate, .22 pellets (16.5 gr)
needed a minimum velocity of 245 fps to perforate human skin, and the .38
RN bullet (113 gr) needed 190 fps to achieve perforation. He provided some
more specific information on the .177 pellet. For the 8.5 grain pellet,
when the velocity was 290 fps the pellet imbedded itself in the skin; when
the velocity was increased to 330 fps the pellet would just perforate the skin.
When the velocity was increased to 365 fps perforation always occurred. The
target in each case was a human lower extremity.

All of the above work was based on relatively blunt bodies and much of it
was done using spherical projectiles so you can easily determine the
sectional density.

Maybe this info will help clarify things some.

geoff kotzar