DiMaio-Minimal Velocities Necessary For Perforation of Skin by Air Gun Pellets and Bullets

 

V . J. M . D i M a i o 1 M . D . ; A . R . C o p e l a n d 2 M . D . ;

P . E . B e s an an tt - M a t t h ew ew s 3 M . D . ; L . A . F l e t c h e r ; 4 a n d A . J o n e s 4

Minimal Velocities Necessary for Perforation of S k i n b y i r G u n P e l le l e t s a n d B u l le le t s

RE FE RE NC E: DiMaio, DiMaio, V. J. M ., Copeland, A. R., Besant Besant-Matt -Matthews, hews, P. E., Flectcher, Flectcher, L. A., Velocitie tiess Necessa Necessary ry for Pedo ration of Sk in by ir Gu n Pell Pellets ets and a nd Jon Jonee s, A., M inim a l Veloci Bulle ts, Jour nal o f Forensic Sciences, Sciences, JFSC A, Vol. 27, No. 4, Oct. 1982, pp. 894-898. ABSTRACT. A series of tests were conducted to determine the velocities necessary for lead air gun pell pellets ets (cali (calibers bers .177 and .22) and caliber .38 lead bull bullets ets to perforate skin. Hu m an iower extremit extr emities ies w ere used. used. Caliber .17 7 air gun pell pellets ets weighing weighing 8.25 grains grains re quired a m inimu m velocity loci ty of 101 m /s (331 ft/s) to perforate perforate skin skin.. Th e energy per a rea of presentation ratio E / a was 1 :8 :8 6 m ' k g / c m 2. Caliber .22 air gun pell pellets ets weighing weighing 16.5 grai grains ns needed a m inim um velo velocit cityy of 75 m/s (245 ft/s). The E / a was 1:3 m .k g /c m 2. A roun d nose, caliber caliber .38 lead lead bullet weighing weighing 113 grains perforated skin at 58 m/s (191 ft/s). The E / a w a s 1 .9 .9 5 m ' k g / c m 2, These studies appear to indicate that lightweight projectiles need greater velocity to perforate skin than do larger caliber, cali ber, heav ier bullets bullets.. K EY W OR D S: criminali criminalisti stics, cs, ball ballist istics ics,, air guns

K n o w l e d g e o f t h e m i n i m u m v e l o ci c i ty t y n e e d e d b y a b u l l e t o r m is i s s il il e t o p e r f o r a t e s k i n m a y b e o f g r e a t i m p o r t a n c e t o a f o r e n s i c p a t h o l o g i s t o r a f i r e a r m s e x a m i n e r i n v o l v e d in in a c a s e o f a s s a u lt l t o r a t t e m p t e d h o m i c i d e w i t h a n a i r g u n . P r o o f t h a t a n i n d i v i d u a l a ir ir w e a p o n i s c a p a b l e o f in i n f l i c t in in g s e v e r e o r l e t h a l w o u n d s i s n e c e s s a r y f o r s u c c e s s f u l p r o s e c u t i o n o f s u c h a c a s e . T h i s w o u n d i n g p o t e n t i a l d e p e n d s o n t h e a b i li li ty t y o f a m iiss s il il e f i r e d f r o m s u c h a g u n t o p e r f oor a t e s k i n a n d t h u s r e a c h a v i t a l o r g a n . K n o w l e d g e o f t h e m i n i m a l v e lo l o c i ty ty n e e d e d t o p e r f o r a t e s k in in i s a ls ls o i m p o r t a n t i n d e t e r m i n i n g t h e m a x i m u m d i s t a n c e a t w h i c h a b u l l e t f i r e d f r o m a firearm is capable of penetrating the body. A r e c e n t r e v i e w o f t h e l i t e r a t u r e [ I ] o n p e r f o r a t i o n o f s k in in b y b u l l e t s a n d m i s s il il e s c o n c l u d e d t h a t , f o r a m i s si s i le l e t o p e r f o r a te t e s k i n a n d e n t e r u n d e r l y i n g s u b c u t a n e o u s t is is s u e a n d m u s c l e , a m i n i m u m v e l o c it it y o n t h e o r d e r o f 7 0 m / s ( 23 2 3 0 f t /s / s ) i s n e c e s sa sa r y w i t h a n e n e r g y p e r a r e a o f p r e s e n t a t i o n r a t i o E / a o f ap a p p r o x i m a t e ly l y 2 .1 .1 m . k g / c m 2 E / a = w v / 2 g r , w h e r e w = w e i g h t o f m i s s i le l e , v = v e l o c i ty ty , g = g r a v i t y , a n d r = r a d i u s ) . T h a t r e v ie ie w p o i n t e d o u t , h o w e v e r , t h a t t h e r e w e r e a n u m b e r o f d e f i c ie i e n c i e s i n t h e p u b l i s h e d s t u d ie ie s . I n v i ew e w o f t h i s, s, t h e a u t h o r s conducted a series of experiments to try to gain additional knowledge on the subject. Received for publication publication 1 M arch 1982; acce pted for publicati publication on 19 M arch 1982. 1Chief medical exam iner, Bex ar County, San Antonio, T X. 2Pathologist, Oklahoma City, OK. 3Medical examiner, Dallas County, Dallas, TX. 4Firearms examiners, Dallas, TX.

89

Copyright © 1982 by ASTM International

 

DIMAIO ET AL

.

A I R G U N P E L L E T V E L O C IT IT IE IE S

89

Method

T h e t e s t m a t e r i a l c o n s i s t e d o f l eg e g s re r e m o v e d a t s u r g e r y , a s w e l l as a s tw t w o l eg eg s r e m o v e d f r o m a b o d y d o n a t e d t o S o u t h w e s t e r n M e d i c a l S c h o o l f o r d i s s e c t io io n a n d r e s e a r c h . I n m o s t i n s t a n c e s t h e s u r g i ca c a l s p e c i m e n s w e r e o b t a i n e d i m m e d i a t e l y a ft ft e r s u r g e r y w i t h o u t a n y i n t e r v e n i n g r e f r i g e ra ra t i o n . T h e a n a t o m i c a l s p e c i m e n s w e r e f r o m t h e b o d y o f a y o u n g v i c t i m o f a m o t o r v e h i c l e a c c i d e n t . T h e y w e r e r e f r i g e r a t e d f o r a fe fe w d a y s p r i o r t o e x p e r i m e n t a t i o n . I d e n t i c a l b a l l is is tic tests on both nonrefrigerated and refrigerated specimens revealed no differences in the r e s i s ta ta n c e o f s k i n to t o p e n e t r a t i o n b y m i s si s i le l e s . T h e r e f o r e , i t a p p e a r s t h a t r e f r ig ig e r a t i o n , a t l e a s t f o r a s h o r t t i m e , d o e s n o t s i g n i f ic ic a n t l y c h a n g e a n y b a l l i s t i c c h a r a c t e r i s t i c s o f s k i n . Th e extremities were suspen ded im me diately adjace nt to a pair of chrono graph screens so t h a t t h e i m p a c t v e lo l o c i ty t y o f t h e m i s s il il e s o n t h e s k i n c o u l d b e d e t e r m i n e d f o r e a c h s h o t . T h e w e a p o n s u s e d f o r t h e t e s t w e r e a c a l i b e r .177 a i r ri ri f le le ; a . 2 2 p u m p a i r p i st o l a n d a . 3 8 S m i t h a n d W e s s o n 5 1 - m m ( 2 - i n . ) b a r r e l r e v o l v e r . T h e 0.177 p e l l e t s w e r e o f w a s p - w a i s t Diablo style, weighed an average of 8.25 grains, and had an average diameter of 4.369 mm ( 0 .1 .1 7 2 i n . ) a t t h e t i p . T h e 0 . 22 22 p e l l e t s w e r e o f t h e D i a b l o s t y l e a n d w e i g h e d a n a v e r a g e o f 1 6. 6. 5 g r a i n s w i t h a n a v e r a g e d i a m e t e r o f 5.461 m m ( 0 .2 .2 1 5 i n . ) . C a r t r i d g e s f o r th t h e c a l i b e r 0 .3 .3 8 r e v o lv lv e r w e r e h a n d - l o a d e d w i t h l l 3 - g r a i n r o u n d - n o s e b u l l e t s h a v i n g a d i a m e t e r o f 9 .1 .1 1 9 m m ( 0 .3 .3 5 9 i n . ) . D i f f e r e n t p o w d e r l o a d s w e r e u s e d t o v a r y v e lo l o c i ty ty . T h e i m p a c t v e l o c i ty ty o f a i r g u n p e l l e ts ts o n t h e s k i n w a s v a r i e d b y a l t e r i n g t h e n u m b e r o f p u m p s p e r s h o t a s w e l l a s t h e d i s tance between target and weapon. Results

Ta b l e 1 g i v e s t h e r e su l t s o f o u r t e st s w i t h t h e c a l i b e r .1 .1 7 7 a i r r i fl fl e . A t a v e l o c i t y o f 8 8 m / s ( 29 29 0 f t / s ) a p e l l e t e m b e d d e d i t s e lf lf i n ( p e n e t r a t e d ) t h e s k i n . C o m p l e t e p a s s a g e th th r o u g h t h e s k i n ( p e r f o r a t io i o n ) w i t h l o d g e m e n t i n t h e u n d e r l y i n g s o f t ti t i s s u e o c c u r r e d i n i ti t i a l ly ly a t 1 01 01 m / s ( 33 33 1 f t / s) . A t v e l o c i ti ti e s o f 11 11 1 m / s ( 36 36 5 f t / s) a n d h i g h e r , p e r f o r a t i o n a l w a y s o c c u r r e d . T h e E/a a t 1 01 0 1 m / s i s 1. 1. 8 5 m . k g / c m 2 . T a b l e 2 g i ve v e s t h e r e s u l ts t s o f th t h e t e s t s w i th t h t h e . 2 2 a i r g u n . A p e l l e t e m b e d d e d i ts ts e l f i n t h e s k i n a t 6 8 m / s ( 22 22 3 f t / s ) . P e r f o r a t i o n o c c u r r e d i n i t ia i a l l y a t 7 5 m / s ( 2 45 4 5 f t / s ) a n d w a s c o n s i s tte n t a t 8 7 m / s ( 2 8 5 f t / s ) a n d h i g h e r . T h e E/a a t 7 5 m / s i s 1 .3 .3 0 m k g / c m 2 . T a b l e 3 l is i s t s o u r r e s u l t s w i th t h t h e c a l i b e r . 38 38 b u l l e t . P e n e t r a t i o n o f t h e s k i n o c c u r r e d a t 5 1 m / s ( 1 66 6 6 f t /s / s ) , w i t h p e r f o r a t i o n b e g i n n i n g a t 58 5 8 m / s ( 1 91 9 1 f t / s ) . T h e E/a a t 5 8 m / s i s 1 . 9 4 m . k g / c m 2.

iscussion

In the pas t 80 years, four major studies have been published c oncerning experim ental att e m p t s t o d e t e r m i n e t h e v e l o ci c i ty t y n e c e s s a r y f o r p e n e t r a t i o n o f s k i n b y b u l l e ts t s a n d m i s s il il e s [2 5]. O n l y t w o o f t h e s e p a p e r s m e r i t a t te te n t i o n i n o u r o p i n io io n . T h e f i r s t a n d p e r h a p s t h e b e s t a r t i c l e w a s b y Jo u r n 6 e i n 1 9 0 7 [ 2] 2] . H e n o t e d t h a t m i ssi l e s w i t h a v e l o c i t y o f 8 0 t o 2 0 0 m / s ( 26 26 2 to 656 ft/s), which rebounded from the skin of horses, penetrated up to 20 cm (7.9 in.) of m u s c l e a f t e r t h e s k i n h a d b e e n r e m o v e d . U s i n g h u m a n c a d a v e rs r s , J ou o u r n6 n6 e f o u n d t h a t a n l l . 2 5 - m m ( 0 . 4 4 3 -i -i n . ) d i a m e t e r l e a d b a l l w e i g h i n g 8 . 5 g , s t r i k i n g s k i n a t a v e l o c i ty ty o f 60 60 m / s ( 19 19 7 f t / s ) , p r o d u c e d o n l y s u p e r f i c i a l s k i n d a m a g e , r e b o u n d i n g w i t h o u t p e n e t r a t i o n . A t a v e l o c it it y o f 7 0 m / s ( 2 30 30 f t / s ) , t h e b a l l p e r f o r a t e d s k i n , p e n e t r a t i n g i n t o U n d e r l y in in g m u s c l e f o r s e v e ra r a l c e n t i m e t r e s . T h e E/a f o r t h i s la l a s t s h o t w a s 2 . 14 14 m . k g / c m 2 . T h e s e c o n d a r t i c l e w a s b y M a t t o o e t a l [ 3] 3]. E v e n t h o u g h a l m o s t 7 0 y e a r s s e p a r a t e t h i s a r t i c le l e a n d t h a t o f J o u r n 6 e , t h e r e s u l ts t s w e r e a lm l m o s t i d e n t i c a l . M a t t o o e t a l u s e d a m i s s i le le 8 . 5 m m i n d i a m e t e r ( a l m o s t e x a c t l y t h r e e f o u r t h s t h e d i a m e t e r o f t h a t u s e d b y J o u r n 6 e) e) a n d w e i g h i n g 4 . 5 g ( ju ju s t o v e r h a l f t h e w e i g h t ) . A b r a s i o n s o f t h e s k i n o c c u r r e d a t 6 2 m / s ( 20 20 2 f t / s ) . P e r f o r a -

 

89

JOURN

L

OF

FO R E N S IC FO IC

SCIENCES

i r r i flfl e . T A B L E 1 - - R e s u l t s w i t h t h e . 1 7 7 a ir

Im pact Veloci Velocity, ty, ft/ s b 241 260 273 273 278 280 285 290 292 297 311 315 317 317 317 321 328 331 331 3336 8

351 352 358 365 368 370 380 381 402 406 407dd 407

Penetra ted Skin

Perforated Perforat ed Skin

Depth of Perforation in Muscle, mm

4-c 4-c +c

+ +c 4-

4m

+

17 '13

4-

+

'1'7'

+ 44+ + 44+

4444_ 4+

'4' 28 15 15 10 not re c orde d 20

4+

15

,4- = ye s, s, -- = no, a nd .. . = de te rmina tion tion c a nnot be ma de . bl ft/s = 0.305 m/s. CBase projecte projectedd fro m skin, dThirteen dThirt een other velocities velocities were recorded (409, 416, 418, 419, 424, 43l, 432, 438, 450, 482, 483, 488, and 500 fl/s) . Th e pell pellets ets perforated the skin at all of tthese hese velociti velocities. es.

t i o n o f s k i n w i t h p e n e t r a t i o n i n t o u n d e r l y i n g m u s c l e to to a d e p t h o f 2 . 9 c m ( 1 . 1 4 i n .) .) o c c u r r e d a t a v e l o c it i t y o f 71 71 m / s ( 2 3 4 i f / s ) w i t h t h e E / a f o r t h is i s l a t t e r m i s s il il e b e i n g 2 . 06 0 6 m ' k g / c m 2. 2. B o t h J o u r n 6 e a n d M a t t o o e t a l i n t h e i r s t u d i e s f a il il t o d e t e r m i n e i f a m a r k e d d i f f e r e n c e i n m a s s a f f e c ts t s t h e v e l o c i ty t y n e c e s s a r y f o r p e r f o r a t i o n O f s k i n . B o t h o f t h e i r s t u d i e s i n v o l v e d r e l aat i v e ly ly l a r g e c a l i b e r (1 (1 1 . 2 5 a n d 8 . 5 r a m ) , h e a v y ( 8 . 5 a n d 4 . 5 g ) l e a d b a l l s . M o s t f o r e n s i c s c iie n c e c a s e s in in w h i c h d e t e r m i n a t i o n o f p e r f o r a t i o n v e l o c it it y i s i m p o r t a n t i n v o l v e s m a l l c a l i b e r ( 0 .1 . 1 7 7 a n d 0 . 2 2 ), ) , l i g h t w e i g h t p e l l e ts t s . O u r s t u d y u s e d s u c h m i s s il il e s a s w e l l a s a h e a v y , b u l l e t s h a p e d p r o j e c t i l e o f r e l a ti t i v e l y s t a n d a r d s iz i z e ( 9 . 1 1 9 m m [ 0 .3 . 3 5 9 i n . ]) ] ) . O u r d a t a s e e m t o i n d iicate that m ass does have an effect on the velocity necessary to perforate skin. Th is conclus io i o n is is s h o w n b y c o m p a r i n g t h e d a t a f r o m t h e 0 . 1 7 7 p e l l et e t s a n d t h e 0 . 38 3 8 b u l l e ts t s . P e r f o r a t io io n w i t h t h e 0 . 1 7 7 p e l l e t i n it i t i a ll ll y o c c u r r e d a t 1 0 1 m / s ( 33 33 1 i f / s ) , w h i l e t h a t o f t h e 0 . 3 8 b u l l e t o c c u r r e d a t 5 8 m / s ( 19 19 1 f t / s ) . T h e 0 . 2 2 p e l l e t f e l l i n b e t w e e n a t 7 5 m / s ( 2 4 5 f t / s ) . O f n o t e i s t h e f a c t t h a t t h e l e a d c a l i b e r 0 .3 .3 8 b u l l e t c l o s el el y a p p r o a c h e s i n c a l i b e r ( 9 r a m ) a n d m a s s t h e m i s -

 

DIMAIO DIMAI O ET AL 9 AIRGUN PELLET VELOCITIES

897

T A B L E 2 Resu lts with the .22 ai airr gun. a Impa ct Ve loc loc ity ity,, f t/ s b 205 212 223 233 235 237

Penetrated S kin

P e r f o r a t ed ed S kin

+

--

+

'q-"

244 245

245 246 247 257 258 258 259 260 262 263 264

----+~ +

-+

+

--

+

'~-

++

+--

+ + + + + + + +

'q-' + + + + + + +

265 267 267 268 272 274 283 285 292 295 298 306 307 312 316 a + = y es es , - - = n o , a n d . . . bl f t/s = 0. 0.305 305 m /s . CBase flush w ith skin.

= determination canno t be made.

s il i l es e s u s e d b y J o u r n 6 e a n d M a t t o o e t a l. l . W i t h t h e . 3 8 S p e c ia i a l re r e v o l v e r, r , t h e v e l o c i ty ty n e c e s s a r y f o r t h e b u l l e t to t o p e r f o r a t e 5 8 m / s ( 19 1 9 1 f t / s ) , w a s v e r y c lo lo s e t o t h a t o f J o u r n 6 e , 7 0 m / s ( 2 3 0 f t / s ) a n d M a t t o o e t a l, l , 7 1 m / s ( 2 34 34 i f / s ) . T h u s , o n t h e b a s i s o f o u r e x p e r i m e n t s w e c o n c l u d e t h a t l i g h t w e i g h t m i s si s i le le s , s u c h a s 0 . 1 7 7 p e l l et e t s , r e q u i r e a v el e l o c it i t y o f a t l e a s t 1 01 0 1 m / s ( 3 31 31 f t / s ) t o p e r f o r a t e s k i n . I n c o n t r a s t , i f t h e m i s s il i l e i s h e a v y , m o r e l i k e t h a t o f a r e g u l a r c a l i b e r 0 . 3 8 b u l l e t , a m i n i m u m v e l o c it it y o f 5 8 m / s ( 1 91 91 i f / s ) i s n e c e s s a r y . T h i s l a s t o b s e r v a t i o n i s o f i m p o r t a n c e i n t h a t i f a s t a n d a r d p i s t o l b u l l e t m i s s e d o r p e r f o r a t e d i t s t a r g e t i t w o u l d b e d a n g e r o u s a s lo l o n g a s it i t h a d a v e l o c it it y o f 5 8 m / s (191 if/s) or more. C o m p a r i s o n o f th t h e E / a v a l u es e s i n o u r t h r e e t e s t s t o r e s u l ts ts o f J o u r n 6 e a n d M a t t o o e t a l s h o w e d f i n d i n g s a p p r o x i m a t e l y e q u a l f o r t h e 0 . 1 7 7 p e l le l e t s a n d 0 . 3 8 b u l l e t . T h e 0 . 2 2 p e l le le t , E / a . however, had a lower

 

  9

J O U R N A L O F F O R E N S IC IC S C I E N C E S

TABLE 3 - - R e s u l t s w i t h c a l i b e r . 3 8 r o u n d - n o s e b u l le le t , a

Imp act Vel Veloci ocity, ty, ft/s b

Penet rated Skin

Perfora ted Skin

145 145 159 15 9

---

.. ..

160 160 166 16 6 I66 169 16 9 173 177 191 238 238 314 322 332

--+c ---

.. . .. . _ .. . .. .

+ + + + + +

+ + + + + +

Depth of Perforation in Muscle mm

25 60 50 45 70 d

a+ = yes, -- = no, and ... = determination cannot be made. bl ft/ s = 0. 0.30 305 5 m/s. CBas CB asee flush with skin. aExited.

eferences

[1]] DiMaio, V. J. [1 J. M., Pen etra tion and Perforatio n of Skin by Bullets and Mis Missil siles: es: A Revi Review ew of the Literature, A m e r i c a n J o u r n a l o f F o r e n s i c M e d i c i n e a n d P a t h o l o gy g y , Vol. 2, No. 2, June 1981, pp. 107-110. [2]] Journ6e, C., Rapp ort entre force vive des balles [2 balles et la Gravit6 Gravit6 des Blessures Blessures qu'elles peuvent Causer, R e v u e d A r t i l le le r i e , Vol. 70, No. 1, 1907, pp. 81-12 81-120. 0. [3]] Mattoo, B. N., Want, A. K., and Asgekar, M. D., Casualty Criteria [3 Criteria for Woun ds from Firearms with Special Reference to Shot Penetration--Part II, J o u r n a l o f F o r e n s i c S c i e n c e s , Vol. 19, No. 3, July 1974, pp. 585-589. [4]] Grund fes t, H., Korr , I. M., McMillen [4 McMillen,, J. H., an d Butler, E. G., Bal Ballis listic ticss of the Penetrat ion of Hu man Skin by Small Spher es, Commi ttee on Medi Medical cal Research of the Office of Sci Scient entifi ificc Research and Devel opmen t, Mis Missil silee Casualties R eport No. 11 11,, 6 July 1945. 1945. [5]] Sperrazza, J. and Koki nakis , W., Bal [5 Ballis listic tic Li mits of Tissue and Cloth ing, A n n a l s o f th th e N e w Y o r k A c a d e m y o f S c ie ie n c e s. s. Vol. 152, No. 1, 1968, pp. 163-167. Address reque sts for re prints o1: additional information to V. J. M. DiMaio, M.D. Chief Medical Examiner Bexar County 600 N. Loons St. San Antonio, TX 78207