Article from the American Rifleman

    » .

r \

By JA\^ES P. COWGILL

■J , I'w k-ii'ci" -o arc various haniipun car- 
j. • ,i;o..-cs’ Ihis micsuon has always 

0 -1.1. c>l imicl> discussion within the fire- 
.u;,.s ir.iicniiiy and revealed widely di­
sc. sC .'pic.s’iis. One reason for the great 
'.ir.ee ol he'...-l' I'n the subject is the fact 

e ;bi; ' .is been no universally accepted 
.1, d.il.i on handgun projectile per-

iiMiiuiacc.
1: you crease .someone's fender with 

oi.i" a.iloniobile. forms will be filled out 
..s iCsinied by law which report in con- 

• b!e detail .ill peitinen: aspects of the 
...cu.cm, such as speeds, weather, visibility 

d ir.illic conditions. Ihis information, 
ccled both n.itionally and locally, is 

, , ;o assemble an impressive body of
si.iiis; cs. No such reporting system exists, 
noweser, to. gunshot wounds or gunfights.

1 h.s .u" cnee of qualilied data permits 
opinions .in bullet performance to be
b. ise.l or. 'icry limited stimples—related by 
he.u'.o ix-si .ind by f.intasy at worst, 
ri.uh suocc; ,o exaggeration. Critical re- 
 ̂ u .1 0 .1 ..cl design .md construction, pro- 

'  n. ch.irge. b.irrel length or aiming
C. .U.' .s not uniformly applied. The vul- 
r,e'..b,::t> Ilf the i.irget. an evaluation of 
i.i.m..r .in. lomy .md physiology, is 
..Is, ne..;;csiej Opinions formed with in- 
cor; .c and sometimes inaccurate infor- 
m..; • • . .c.ui to failacious “part for whole” 
ger.c. ......ations which may wrongly ap-

F.iL.or’s Sole: While most S’HA Meni- 
her^ use firearms piimarily for sport, a 
pi ret'iih.ee of them are law enforcement 
oflieers and an even larpcr percentape be­
lieve in firearms for family or personal 
protivuin. The relative performances of 
/!,. cartriJpes in incapacilatinp an
losa-.lant are. therefore, of legitimate in­
terest. For that reason The American Rille- 

■ .ishes here an in-ileplh research of 
o. ',(■./ V. hich IS likely to he quoted for 

\ . r f
. hr irtoniialioii given here was derived 

■ ’ tUnernment tests and sources.
n represent any NRA recom- 

,1 , ndi. or vieivpoint. Its sole short-
c. .mhre a, direct application to police
r, II, s the reliance placed on only
a . - . .d typical shot dispersion: at the 
/, ,( loldiers shooting MI 9 I I  service
arm .i ,i. in under stress. If other arms and 
amn ,a.lion can he shot far more accu- 
raiei i . stress situations, the relative rank­
ing of i.ir.miinilion for incapacitating effect 
is siihjei t to i hange.

Anvone r.ishirig further information may 
write: I.esie. I) Shuhin, National Institute 
of Imw F.nforeement and Criminal Justice, 
Udi. Department of Justice, Washington,
D. C. 20531.

38

praise entire families of weapons and loads.
New research, just completed, now con­

siders handgun shootcr-wcapon-cartridgc- 
target aspects as an entire system. For the 
first time, these phenomena have all been 
considered at once.

The National Institute of Law Enforce­
ment and Criminal Justice sponsored the 
research to determine relative handgun 
cartridge elTectiveness as definitively as 
modern science and technology will allow. 
The purpose is to help law enforcement 
agencies make considered decisions in 
their choice of duty sidearms and loads. 
The data resulting, from this research, pub­
lished with this article, provides some sur­
prising revelations and dramatic changes 
from past perspectives on handgun termi­
nal ballistics.

The Law Enforcement Standards Lab­
oratory of the National Bureau of Stand­
ards was responsible for the research, 
which was conducted at the U.S. Army 
Ballistic Research Laboratories, Aberdeen 
Proving Ground, Md, Th<! characteristics 
of the cartridges studied included relative 
incapacitation of human targets, ricochet 
hazards to innocent bystanders and pene­
tration characteristics in hard surfaces. 
Relative dispersions of various cartridges 
and arms in the field were not studied.

Commercially available handgun bullets 
of all types of conventional construction 
were tested. Under conditions of equal 
caliber, mass, velocity and placement, they

ranked in incapacitation efiiciency from 
highest to lowest as follows;

Lead Hollow Point 
Jacketed Hollow Point 
Semi-Wadclitter 
Wadcutter 
Jacketed Soft Point •
Lead Round Nose 
Full Metal Jacketed

A bullet of uneonventional design called 
the Glaser Safety Slug was also tested with 
impressive results. This projectile, avail­
able only to law enforcement agencies, 
consists of a copper jacket filled with No. 
12 shot and viscous liquid, capped with 
a fiberglass-Tedon plug. Upon impact, 
the bullet penetrates and the plug dis­
integrates, releasing the shot to eonvey 
their energy to the target in a controlled 
dispersion. Since this bullet expends all its 
energy in the target in most situations, 
there is little danger of injury to bystand­
ers from over-penetration in police gun- 
fight situations. Ricochet hazard is vir­
tually eliasi/iirtnl because, upon .striking a 
hard surface the shot are immediately re­
leased and dispersed to dissipate their en­
ergy as many small, low-mass particles.

Despite widely varying and tightly held 
opinions on handgun cartridge effective­
ness, no valid method for evaluating bul­
let performance based upon quantifiable 
theory and provable by demonstrable ex­
perimentation has existed. Now, the latest 
and most accurate scientific apparatus and 
instrumentation and innovative mathe­
matical modeling and computer simulation 
have been used together to expand the 
scope of the research considerably, beyond 
the limitations of practicable physical 
experimentation.

Study of the ability of cartridges to in­
capacitate human targets required the fol­
lowing definition, operable in the law en­
forcement context:

This schematic of the Ballistics Research Laboratories test set-up shows how velocity, 
bu lle t deformation, and cavity and wound channel development data were collected  
simultaneously in actual firings.

THE A ME R I C A N  RI FLEMAN



Instant incapacitation is that which 
will render the assailant incapa­
ble of posing a continued threat 
to the safety of the olliccr by 
use of a hand-held weapon. Such 
injUry may include clinical death, 
unconsciousness, biomedical dys­
function, etc., but pain may not 
be considered a contributing fac-

areas to instant incapacitation, as defined. 
An anatomical model of the human form 
WHS divided into horizontal, inch-thick 
sections. Each of these horizontal sections 
was divided into rectangular solids by ver­
tically imposing a 0.2-inch square grid on 
each. A team of physicians from the Uni­
versity of Maryland Shock-Trauma Center 
assigned a numerical value to each rec- 
tangular solid (over 150,000 total) which 
represents its individual relative sensitivity 
to instant incapacitation. This analysis of 
human vulnerability to instant incapacita­
tion by handgun bullets was entered into 
automatic data processing equipment as 
"Computer Man," the vulnerability model
for the study. , . . ,

Hit dispersion data was obtained from 
Army Human Engineering Laboratory ex­
perimentation which involved live firing

by soldiers using cal. .45 service pistols to 
shoot at pop-up targets in a stress-type 
scenario. The systems analysis technique 
used can accept other dispersions which 
may be developed for any shooter/ammu- 
nition/handgun combination, such as the 
hit distribution fired by policemen with 
service ammunition and duty revolvers. 
This has not yet been done, and the results 
might greatly affect the published ratings.

These two models, the vulnerability rep­
resentation and the hit distribution data, 
were played against each other in a com­
puter. Since the "Computer Man" repre­
sented a dangerous assailant, its posture 
alignment was always frontal, facing the 
defending officer. Each round was 
or weighted against its penetration of the 
anatomical model with respect to incapaci­
tation potential. Misses were zeroes.

There are three critical elements in en­
counters between law enforcement officers 
and their ass.ulants: target vulnerability, 
hit distribution .ind bullet terminal bal­
listics. D.iu representing these elements 
were used as inputs to the study to pro­
duce a Relative Incapacitation Index (RIl) 
number for each cartridge tested. The 
methodology used has made a significant 
contribution to knowledge because, for the 
first lime, all of the most significant identi­
fiable variables in the encounter situation 
have been considered to produce quantifi­
able results. Previous efforts to quantify 
performance usually considered only the 
physical performance of the bullet, neglect- 
ing critical factors of target vulnerability 
and hit probability and distribution.

Target vulnerability was UetermincU by 
analyzing a model of the human body to 
determine the relative sensitivity of all

This is the dispersion 
fired by relatively un­
trained shooters with 
the M 1911 cal. .45  
s e r v i c e  p i s t o l  i n 
stress-type scenarios. 
Project funds were
not unlim ited , and d if­
ferent dispersions—  
using, for instance, 
easier-to-shoot guns 
__were not obtained.

4 .6 .6 1.0 1.2 
DISTANCE IN METRES

,, ■) t ' ' -  *

39
O C T O B E R  1975



Performance of Commercially Available Handgun Ammunition'
B A R R E L M E A S U R E D

C A L IG E R
W E IG H T
( g r a in s ) B U L L E T  T Y P E M A N U F A C T U R E R

L E N G T H
( in )

V E L O C IT Y  
( fp s )  ( m / s )

R l
IN D E X

2 0 0 J H P SPEER 4 .0 0 1 2 7 7 3 8 9 5 4 .9
. 3 b 7 t\*A u 9 6 S A F E T Y  S L U G D E A D E Y E  A S S O C 4 .0 0 1 7 2 5 5 2 5 5 0 .0
.3 5 7  M A u 9 6 S A F E T Y  S L U G D E A D E Y E  A S S O C 2 .7 5 1 6 1 5 4 9 2 4 6 .0
.3 S  S P E C 9 6 S A F E T Y  S L U G D E A D E Y E  A S S O C 2 .0 0 1 4 9 6 4 5 5 3 7 .5
,3 S  SPEC 1 2 5 J H P R E M IN G T O N 4 .0 0 1 1 0 8 3 3 7 2 5 .5
.4 5  A U T O 1 3 5 J H P R E M IN G T O N 5 .0 0 8 9 5 2 7 2 2 1 .1
.3 5 7  ,VAG 1 5 3 J S P (H I -V E L ) F E D E R A L 2 .7 5 1 1 9 5 3 6 4 1 8 .7
.3 5 7  M A G 1 5 8 J S P SPEER 2 .7 5 1 0 3 0 3 1 3 1 7 .5
.4 5  A U fO 1 8 5 W C  (T A R G E T M A S T E R ) R E M IN G T O N 5 .0 0 8 2 1 2 5 0 1 4 .7
,3 S  SPEC n o J H P (L O T -Q 4 0 7 0 ) W IN C H -W E S T E R N 2 .0 0 9 5 6 2 9 1 1 4 .0
.3S SPEC 1 4 3 W C R E M IN G T O N 4 .0 0 7 4 1 2 2 5 1 2 .4
.3 5 7  M A G 1 5 3 J H P S M IT H -W E S S O N 2 .7 5 9 8 2 2 9 9 1 1 .1
.3 3  S P E C n o J H P SPEER 4 .0 0 8 5 7 2 6 1 1 0 .5

9 M M 1 2 5 J S P S P E E R 4 .0 0 1 0 5 8 3 2 2 9 .9
.3 3  SPEC 1 2 5 J H P R E M IN G T O N 2 .0 0 9 1 1 2 7 7 7 .0
.4 5  A U T O 2 3 0 FJ W IN C H -W E S T E R N 5 .0 0 7 4 0 2 2 5 6 .5
.3 3  S P E C 1 5 8 LR N F E D E R A L 4 .0 0 7 9 5 2 4 2 5 .0
.3 3  S P E C 1 5 8 L R N R E M IN G T O N 2 .0 0 6 9 4 2 1 1 4 .4
.3 3  S P E C 2 0 0 L R N  (L U B A L U V ) W E S T E R N  b U P -X 2 .0 0 5 9 2 1 8 0 4 .1
.2 2  LR  C A L 3 7 L H P W IN C H -W E S T E R N 2 .0 0 8 7 2 2 6 5 2 .3
.3 8  S P E C 6 4 S H O R T  S T O P M B A 2 .0 0 6 7 1 2 0 4 0 .4

ar
a(
P<
si

1 he resiiU of this d.iia m.mipiilalion is 
a curse which shows the \ ulnerabiliiy 
inJev with respect to penetration, a com- 
p.'sjte of all the shots lireil tind the entire 
huni.in K'lly. I he cone shows that the 
most Milnertible rcttion. essentially the 
most sensitise pssrtions <if the vital organs, 
occurs at ,i pcneti.ition of tipproxiniately 
4.5 centimeters (about I ’a"). A logical 
conclusion is th.it the more eflicient in­
capacitating rounils ssill trtinsfer more 
momentum (or energy) to the target in 
the vulnerable regions than in the less 
sensitise solumes.

The termin.il ballistics portion of the 
experimentation examined bullet behavior 
in detail by tiring into a tissue simulant, 
blocks m.ide of 20Cc gelatin, on a highly- 
instrumentCkl range. The correspondence 
between the beh.isior of standardized gela­
tin blocks wlien impacted by bullets and 
that of bissly tissue has been established by 
previous ,sf...> oi..geon General research. 
When tissue .s struck by a penetrating pro­
jectile. a iempssr.iry cavity is formed 
around the p.ith of the bullet which may 
be several times the diameter of the pro­
jectile or of the permanent cavity or 
wound ch.mnel. inis phenomenon is of 
extremely short duration, from five tv’ sen 
thousandths of a second, after which the 
elastic and somewhat fluid tissue contracts 
to the dimensions of the permanent cavity 
or wound channel. I he volume of the 
temporary ctivity is proportional to the 
striking kinetic energy of the projectile. 
I he shape of the temporary cavity is im­
portant because Us radius at any penetra­
tion depth can be used to determine how 
much energy is delivered to the target at 
that point. The more efTective projectiles 
will transfer msire energy at the more vul­
nerable peneration depths and thus will

generate temporary cavities of larger di­
mensions at those critical depths.

Considerable effort was spent in the 
measurement of the formation and subse­
quent development of the temporary cav­
ities produced by various cartridges. Bullet 
impact velocity was measured, high-speed 
motion picture photography recorded the 
profile of the temporary cavity and flash 
X-ray exposures were made of the bullets 
as they traversed the gelatin. A dramatic 
“ballooning” effect of the cavity was ob­
served when the projectiles exceeded a 
velocity of approximately 1100 feel per 
second, which is, perhaps coincidentally, 
the speed of sound in air.

The flash X-ray exposures provided five 
images of each bullet as it traversed the 
gelatin block. These shadowgram pictures 
reveal the stability and deformation of the 
bullet during penetration.

The payoff of the research is in the Rel­
ative Incapacitation index (Rll), a man­
ageable and quantifiable number that can 
be used and understood by the law en­
forcement official charged with the deci­
sion of selecting arms and ammunition for 
his department. Rll values were obtained 
by the mathematical technique' of inte­
grating the product of the averaged Vul­
nerability Index and the cross-sectional 
area of the temporary cavity with respect 
to penetration depth. This mathematical 
procedure is designed to score most highly 
the bullets which transfer the most mo­
mentum (or energy) to the target in the 
most vulnerable regions.

The higher RII values do not always go 
to the projectiles which have the most 
kinetic energy or even to those which de­
posit the highest total kinetic energy in 
the target because of the significance of the 
shape of the temporary cavity and its cor­

respondence with the Vulnerability Index 
curve. Remember, temporary cavity values 
were obtained experimentally.

The Rll values published were obtained 
by centering the hit distribution model 
about the center of the "Computer Man" 
torso mass, as is taught in standard fire­
arms training courses. As an exercise in 
computer simulation and analysis, the com­
puter program was run with the center of 
dispersion coincident with the center of 
vulnerability, which is located at about the 
armpit level. Even with the additional 
misses created from raising the aiming 
point, the overall Rll and probability of 
incapacitation were increased significantly. 
This finding may indicate that an officer 
has a better chance of incapacitating his 
assailant by aiming at the armpit level 
rather than the center of the chest, infor­
mation which may have a profound effect 
on future firearms training and doctrine.

Previous efforts at quantifying pistol 
cartridge performance have included Gen­
eral Julian Hatcher’s Relative Stopping 
Power (RSP) formula, first published in 
1935, and Southwestern Institute of For­
ensic Science’s energy deposit-tests in 1974. 
Each approach has its limitations.

Hatcher’s formula multiplied a projec­
tile’s area, half its momentum and a 
“shape factor” determined from bullet con­
struction to obtain an RSP value. A major 
contribution of this formula was the recog­
nition that bullet area and shape have a 
significant impact on effectiveness, a con­
cept thoroughly validated by subsequent 
research. However, the numerical values 
obtained for RSP do not correspond, even 
relatively, to the results of the Aberdeen 
tests. The RSP formula appears to give too 
great a weight to the larger calibers. Also, 
the "shape factor" values, rather grossly

S
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fc
bl
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o
a'
t.i
Ilf
ti
o
a
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n

40 THE A M E R I C A N  RI FLEMAN



,ii I’iii ,ii il\ clu'^cn. I’l'ol'.iHy ilo not 
. t v w . i i . i l i i . -  « ulo spectrum of 
pci to: i-.'..,iicc In i'ullcis of moilcrn con- 
sliiiitn'ii, csi'ccullv vlumii; lict'oim:ition.

i t;c Soutliucstcui Insiaulc of 1-orciisic 
Scic:iccs c\.ilu.ition, coiivluctcJ by N’iiiccnt 
J M. O: M.iio, M D. and his associates, 
chiono.cr.iplieJ scisicc h.imliriin bullets be­
fore enierini; .uid after exiting gelatin 
blocks ti' lietermine the toi:il kinetis energy 
deposited in the i.iiget. NS'ithin the scope 
ot these tests, reassuiitbly good quantifi- 
,iblc, demonstrable indicators ncrc ob­
tained for recommending amnumition for 
l,in enforcement application. The evalua­
tion did not. hosseser, examine the shape 
of the temporary cavity and target vulner­
ability as the l.itcs: lesearch has done. As 
mentioned prexiously, maximum total en­
ergy tr.insfer, does not always mean maxi- 
mun'. inc.ipacit.ition clliciency.

Relative Incapacitation Index (RII) 
xalues of rounds tested ranged from 54.9 
for a jacketed hollow point (JHP) .44 
Magnum to 0.4 for a .38 Spcci.il "bean 
bag" round. Cartridges whose Kll values 
fell between 10 and 25 have been postu­
lated as adequate for service application, 
with the caveat that the guidelines arc 
offered as probabilistic rather than abso­
lute indexes in kccp.ng with the statistical 
nature of the biological data in the study.

How well did sonic of our more familiar 
service rounds perform? Ihe most com­
mon police side.irm ammunition in this 
Cv'untry is the .38 Special 158-gr. lead 
round nose tLRN) cartridge, and our pre­
dominant milit.iry handgun load, is the .45 

23()-gr, full metal jacketed (F,\U) 
load. Of 142 pistol-cartridge combinations 
tested, the most effective .38 Special LRN 
was 99th on the list with an Rll of 9.0. 
The first military-equivalent .45 ACP was 
number 110 with an Rll of 6.7. Each of 
these stand.ird cartridges was clearly out­
classed by a great number of alternate 
loads, including many 9 mm's.

The relative standings vif the various 
cartridges are determined by the sizes and 
shapes of the temporary cavities formed. 
At comp.i.'.ibie non-deforming velocities, a 
larger c.dibcr bullet will yield a higher 
Rll; bevor.d deforming velocities, smaller 
caliber bul.ets of ellicient design may out- 
peiform .a.ger calibers.

The current research has contributed 
greatly to bringing knowledge about rela­
tive handgun cartridge effectiveness out of 
the re.dm of mythology and folklore. The 
concepts and principles developed should 
be useful evermore to the scientific, law 
enforcement and shooting communities. U

ACKNOWLEDGEMENTS 
The author gratefully acLnowleUgev the as- 

Mst.ince of the following research principals; 
Lester D. Stiuhin. Program Manager for Stand­
ards. National Institute of Law Enforcement 
■ind Criminal Justice; Ron Dohbyn, Physicist, 
Law Enforcement Standards Laboratory of the 
.National Bureau of Standards; XVilliam J. 
Bruchey. Jr.. Research Physical Scientist, Bal­
listic Research Laboratories, Aberdeen Proving 
Ground. The suggestions and encouragement of 
Charles S. Petty, M.D., Director and Vincent 
J. ,XI. Di .Xtaio. M.D.. Associate Medical Di­
rector. Southwestern Institute of Forensic Sci­
ences, were greatly appreciated.

O C T O BE R  1975

These representations of the evolution of maximum temporary cavities provide a 
direct comparison of the difference velocity and bullet shape and construction 
can make. On the left is the cavity produced by a typical 158-gr. lead round-nosed 
bullet at 7 70  f.p.s. fired from a .38  Special handgun. At center, the load was a .38  
Special 158-gr. semi-wadcutter at 8 6 0  f.p.s. On the right, and much more impressive, 
is the result from a .357  S&W Magnum 158-gr. jacketed hollow-point bullet at 
1100 f.p.s.
REFERENCES

Beyer, Major James C., MC. (ed.) H'oiind 
Ballisilcs. Washington: U.S. Governmcnl Prim­
ing Office, 1962.

Cowgill, Jim. "A Critical Look at KE and 
RSP," Handlottdtr, (September-October 1975), 
40-41.

Di Malo, Vincent J. M., M.D. et at. “A Com­
parison of the Wounding Effects of Commer-

W-W, l« N ,  SI SSfC
VIIOCIIV ------- s e s m n . t  l» J8 l / i « e l

146"'7i*c ( n 3 | f / i « c )
)|4mA«c

C A V IT Y  P K O F iie  (cm ) 
“ 5.1 0  5.1 10.2 

30 5

dully Available Handgun Ammunition Suitable 
for Police Use,” FBI Law Enforcement BuUetlnt 
(December 1974), 3*8.

Di Malo, Vincent J. M., M.D. "The Effective­
ness of Snub“Nosc Revolvers and Small Auto­
matic Pistols," FBI Law Enforcement Bulletin, 
(June 1975), 10-13.

Dobbyn, R. C., W. J. Bruchey, Jr., and L. D. 
Shubin. An Evaltiation of Police Handgun Am- 
munition: Summary Report. Washington: U.S. 
Department of Justice, August 1975.

Hatcher, Major Julian S. Textbook of Pistolx 
and Rexohers. Marines, N.C.: Small-Arms Tech­
nical Publishing Company, 1935.

At left, temporary cavities from .38  
Special lead round-nosed bullets at 
three velocities are illustrated. The 
correlation between velocity and rad­
ius of the temporary cavity is direct.

S 4 w , J H 4 , 3 5 7  M A O
V I lO C iT Y  ----------( 1 2 4 3 1 / m l

— - 5 2 4 « / m € (1727f/i«) ..........2*ImA»c |l5S f/»M )

“ 10,2
C A V IT Y  7 R O T II I  (cm ) 

-5 .1  0  1.1 10 2

e
10.2 I

At right are cavities from four firings 
of .357  S&W Magnum jacketed  
hollow-points at varying velocities. 
Again, there is direct correlation be­
tween striking velocity and tem po­
rary cavity generation. Note also the 
difference in the results between 
this representation and that shown 
above.

41