Photographic Study of Impact of Ball and AP on Armor Plate

8/14/2019 Photographic Study of Impact of Ball and AP on Armor Plate

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R e p o r t N O 710/?81Va.tertown A r s e n a l December 2 1 , 1?36

F h o 3 o ~ r a p h i cStu.dy o f I ~y p ac tof 3a.11 2nd .4rmor P i e r c i n g Ammunit icn-- n A r m o r P l a t e--------------

T h e o b j e c t o t h i s i n v e s t i p . t i o n w ~ s :1 TQ make a. phot op;r apni c s t u d y of t h e imw2ct of

b a l l a n d a rm or p i e r c i n ? b u l l e t s i n homogeneous a r: ?o r p l a t e .To s tu3y t h e x p t u r e o f d e f o r r n a t i c n ~t a r p p s

n b u l l e t i r n p ~ z t ,

a n d .30 b a l l a mmun it i on on p l a t e r e v e a l s ou nd w v e s ast h e y a r e r e f l e c t e d f rom t n e b ac k s i d e c f t h e p l a . t e a n dt h e s t a r t of new 1vc7ves a s t n e b u l l e t p i e r c e s t h e p l a t e .

2 . P h ot o cr ap h ic s t u d i e s t ak e n by r e f l e c t e d l i q h tof d i f f e r e n t s t a i ~ e s f i r n p ~ c t f Ca.1. 30 a r m o r p i e r c i n gb u . l l e t s ~ r i t h t r i k i n g v e l o c i t y v z r y i n a f r ~ m 100 f o o ts ec on ds t o s e r v i c e v e l o c i t y a.t a d i s t a n c e o f 1 0 0 y a r dsi n d i c s t e t h a t : -

a.) I n ca n de s ce n t p s r t i c l e s of l e a d a r ce v i d e n t a t moment of impact.b ) The j a c k e t m e t a l p e e l s c f f t h e c o r e andi s f l n t t e n e d o u t on The p l a t e a t e w l ys t a g e s o f i m pa ct .c ) Lead s p l a s h an d p a r t i c l e s c f j a c k e t m et ala r e S lolvn o f f a t t n e a r e a o f i m p a ct .


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3. S p ec t ro g ra p h i c a n a l y s i s o f m e t a l l i c p a . r t i c l e sa n d g r a y d e p o s i t c o l l e c t e d on \;rooden members o f t n e a r m c rp l a t e s u p p o r t i s as f o l l o w s :

a . K e t a l l i c P a r t i c l e s Cu, P b, Znb . Gray d e p os i t Cu, Pb, Ze , A l , Zn, IGn, C r

4 . D i s t o r t i c n on t h e r e a r f a c e o f a.rmor p l a t es o m e t i m e s o c c u r s . 5 from a c t u a l p o i n t o f p e n e t ra t i o n .

5 . D i s t o r t i o n o f t h e o u t e r s u r f a c e l a y e r s o fp l a t e n e a r t h e a r e a o f i m p a c t a s r e v e a l e d by m ac ro sc op ice x a m i n a t i o n i s t y p i c a l o f t h a t p r od u ce d by t o r s i o n .

6 . E v i de n c e o f t o r s i o n a l i m p a c t p r o d uc e d byb u l l e t i mp ac t on p l a t e i s r e ve a l e d i n t h e follo1lrini-1; c - .ses :

( a ) The s t u d y o f m i c r o s c o p i c e x a m l n a t i o n o ft n e m e t a l a t a r e a s of i m p a c t.

( b ) S p a l l s wit hav ,e been b lown o f f theb ac k o f t h e p l a t e ,

( c ) s t u d y o f s p i r a l f r a c t u r e s on t h e r e a rf a c e o f p e n e t r a t e d p l a t e .

I n t r o d u c t i o nI n c c n n e c t i o n w i t h t h e p r e s e n t s t u d y of t h e n ec ha ni sm

o f p e n e t r a t i o n o f a rm or p l a . t e , P r o f e s s o r H E E d g e r t o nof t h e ~ d ~ a s s a c h u s e t t sn s t i t u t e of Technclog-y ha.s made av e r y i n t e r e s t i n g an d instru t ive s e r i e s o f p h o to gr ap nso f i m p a c t s of a r m o r p i e r c i n g b u l l e t s on h om og en eo us a r mo rp l a t e , o ne -h al f i n c h i n t h i c k n e ss .


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P r o f e s s o r E d g e r t o n has r e c e n t l y p e r f e c t e d t h et e c h n i q u e o f t a k i n g a c c u r a t e l y t im ed p ho to g ra p hs o fb u l l e t s i n f l i g h t , and a t v a r i o u s s t a g e s o f i mp ac t onp l a t e , t h e d e t a i l s o f wh ich a r e g i v en below.

EXPERI16ENTAL PROCEDUREMethod o f Taking Acc ura t e ly T imdP ho tog raphs

Pre l i m i n a r y e x p e r i me n t s were c o n du c te d a tt h e I " a s s a c h u s e t t s I n s t i t u t e o f T ec hn ol og y on t h e p n o to -g r a p h i c s t u d y o f i mp ac t of c a l i b e r .2 2 an d 30 b a l la mmu n i t i o n o n t h i n s h e e t r u b b e r , 18 gauge aluminum and18 g au ge g a l v a n iz e d i r o n s h e e t . B ot h s i l h o u e t t e a ndr e f l e c t e d l i g h t p h o to g ra ph s were t ak en .

An ex ten s i ve pho to g raph ic s t udy was made a tiva ter to lvn Arsenal dur ing September and October 1036u n de r t h e d i r e c t i o n o f P r o f e s s o r Ed ge rt on i n re g a r d t ot h e i mp ac t o f c a l i b e r .30 a rmo r p i e r c i n g b u l l e t s ons t a n d a r d chromium-molybdenum-vanadium homogeneous armorp l a t e h ea t t r e a t e d t o a Bri ne1 1 ha rd ne ss of 418 . Thes t r i k i n g v e l o c i t i e s of t h e b u l l e t s u s ed v a r i e d from2100 f oo t- se co nd s t o s e r v i c e v e l o c i t y a t a d i s t a n c e o f100 y a r ds . The s i z e o f t h i s p l a t e was 1 2 x 12 x 1/21 .

l l s c a l e on t h e p l a t e was removed by means of sandb l a s t i n g be f or e t h e t e s t .


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P ho t og r aph i c s t u d i e s were a l s o made on t h e r e a rf a c e o f a sa nd b l a s t e d p l a t e , b e f o re , d u r i ng and a f t e rb u l l e t im pa ct i n o r d e r t o d et er mi ne t h e n a t u r e o f t h emechanism of penetrat ion on t h i s p a r t i c u l a r f a c e .

Fur thermore a n a t t e m p t was made t o s t udy t h e ex t e n tof deformat ion a t t h e a r e a of p e a r a t i o n on t h e r e a rf a c e of th e ?Late. To acc ompl ish t h i s t he r e a r f a c eof t h e p l a t e was ground , p o l i s he d and p a r ~ l l e l i n e sone-ha l f i n ch a p a r t were e ngraved h o r i zo n t a l l y ~ n dv e r t i c ~ t l l y n t h i s f ace . pho t og r aph i c s t u dy was m ~ d eb e f o r e , d u r i n g and a f t e r im pa ct , i n o r d e r t o de te rm in et h e amount of d i s t o r t i o n of t h e l i n e s .

l l p l a t e s w ere s e c u r e l y cl amp ed t o a wooden frame-wo rk, t h e r e a r f a c e of t h e p l a t e b e i ng u n p r ot e c t e d.

The appa r a t u s u s ed f o r t a k i n g t h e pho tog r aphsshown i n Fig ur e c o n s i s t e d of t h e f o l l o a i n g u n i t s :

a ) R oc h el l e- s al t p i e z o - e l e c t r i c c r y s t a land a mp l i f i e r a c t u a t e d t h e f l a s h of l i g h t a t t h e c o r r e c ti n s t ~ n t . The a m p l i f i e r c o n s i s t e d of f o u r s t a g e s ofvacuum tubes plus a T h yr a tr o n s p a r k p ro du ci ng c i r c u i t .T h i s h i g h v o l t a g e s p a rk bout 50 000 v o l t s ) was u s e dt o t r i p t h e a r g o n l a m p d e s c r i b e d b e l o w :

b ) s p e c i a l l y c o ns t ru c te d ergon f i l l e dlamp was u s e d f o r pr od uc in g t h e v e ry s h o r t f l a s h ofl i g h t a n d was e x c i t e d b y a c on de ns er c ha rg e. The l e ~ d s


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f o r t h i s t u be were d e s i g n e d t o m in im iz e t h e i n d u c t a n c ei n t h e c on de ns er d i s c ha r g e c i r c u i t . s k e t c h of t h eg e n e r a l a r r a n g e m e n t i s shown i n Figu.re 1 v h i c h S ~ O I Y St h e c o n n e c t i o n s 2nd t n e p o s i t i o n o f t h e c am er a a n dt h e lamp. Argon ga s a t a p r e s s u r e of f o r t y c e n t i m e t e r s

o f mercury) was p u t i n t o t h e t ub e.The s e a l s were 40 m i l t ungs ten ond the ends o f

t h e s e a l s were u s e d s e l e c t r o d e s . c o n d en se r of0 . 5 m i cr o fa r ad c a p a c i t y , c h ar g ed t o a b o ut 6000 v o l t swas c on ne ct ed d i r e c t l y a c r o s s t h e s p e c i a l a rg on t u be .

c ) The ca mer a u s e d f o r t a k i n g t h e p r e l i m i n -a r y impa ct s t u d i e s vras x 1 2 cm Ze i s s Iko n rlrith anf 4 . 5 l e n s o f 150 mm f o c ~ le n g t h . The l e n s was s e ti n t h i s c a s e ~ t l l .

I n t h e p h ot o g ra p h i c s t u d y of a rmo r p i e r c i n gimpc.ct a f 7 . 7 l e n s wi de open w i t h 173 mm f oc a. 1 l e n g t hwas used. l l p h o t o g r ~ p h sw er e t a k e n upon E~ s t m a nt lVer ichromen f i l m2 Macro and Mic ros cop ic Examin8 t i o n

Macro a.nd microscopic examination was made onp l a t e s t e s t e d a t Aberdeen P rov ing Ground i n o r de r t os t u d y t h e f l o w o f m e t a l a t a r e 8 s o f b u l l e t i mp ac t.3 Spec t rog raph ic Ana l ys i s o f Depos i t fromBu l l e t I m p a c t

S p e c t r o g r a p h i c a n a l y s i s ~a smzde on some of thed e p o s i t t ak e n f ro m b u l l e t im pa ct on p l a t e . T h i sd e p o s i t was removed f rom 1*1coden s u p p o r t s of t h e5


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f ra me wo rk s u p p o r t i n g t h e a r m or p l a t e .

D i s c u s s i o n1 P h o t o ~ r a p h i cS tu d y

The p i e z o - e l e c t r i c - c r y s t a l method oft i m i n c t h e f l ~ s h orks v e r y c o n s i s t e n t l y 2 nd q u i c k l y .F or ex an pl e; t n e v a r i ~ t i o n f t h e p o s i t i o n of t h eb u l l e t f ro m t h e mecn v a l u e i n t w el v e ( 1 2 ) p i c t u r e swas l e s s t n a n 1 /2 . Most o f t h i s v a r i ~ . t i o n 8n b ea c c ou n t ed f o r by d i s p e r s i o n o f t h e ~ ~ m m u n i t i o n .

The l l g n t f l a s h e s e a r l y i f t h e f u l l s e n s i -t i v i t y of t h e a m p l i f i e r i s u s e d . T h i s i s a p p a r e n t l ydue t o th e sound wave t h a t i s t r a n s m i t t e d t h r o u g h t h eg un s u p p o r t a n d t h e c ement f l o o r t o t n e c r y st a . 1 s t a n d .A d jus tm e nt o f t h e c ry s t9 .1 p o s i t i o n was f i r s t a p p r o x i -m at e l y d et er mi ne d by c a l c u l ~ t i o n r om t h e e x pe c te dv e l o c i t y o f t n e b u l l e t . F i n r l a dj us tm en t was madev i s u a l l y s i n c e t h e b u l l e t c an be s e e n v i t h t h e f l a sho f l i g h t fr om t h e a rg o n tube

The p h o t o g r a p h i c a l l y - e f f e c t i v e d u r a t i o no f l i g h t fr om t n e a r go n t u b e i s abo ut two micr os e co nd s . Assuming b u l l e t v e l o c i t y o f 2700 f e e tp e r s ec on d t h e b u l l e t w l l move 0.06 of PLn i n c h ,w h i l e t h e e x p o s u r e i s be i ng ms.de. The s l i g h t l yb l u r r e d e dg es of t n e b u l l e t s i n t h e p ho t og r ~. p hs scaused by t h i s e f f e c t thwugh some o f t h e b l u r r i n g


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may b e c a u s e d by l a c k o f ~ c c u r a t e o c u s . The e x p o s u r et i me i s l i m i t e d p r i n c i p a l l y by i n du c ta nc e i n t h ec o n d e n s e r ~ n dn t h e l e a d s . H ow ev er t h e lamp m l yg r e a t l y ex t en d t h e e x po su re t i me i f i t a l l ow s c s c i l l a -t i o n s i n t h e c o nd en se r o r i f t h e g a s i n t h e t u be c on-t i n u e s t o g lo ~ v f t e r t he c u r r e n t ha.s s top ped. The tu bewhose s p e c i f i c a t i o n s a r e g i v en on t h e s c h e m ~ t i c e .y o utof t h e a rr an ge me nt h a s s u f f i c i e n t r e s i s t a n c e t o dampo u t t h e o s c i l l a t i o n s an d nas a v e ry f a . i n t e f t e r g lowt h a t i s n o t e f f e c t i v e f rom a. p h o t o g r ~ ~ p h i ct a n d p o i n t .R e d u c t i o n o f e x p o s u r e t i m e s h o u l d b e p o s s i b l e w i t h ac o n d e n s e r o f l o w e r i n d u c t a n c e . The i n d u c t a .n c e o f t h e0 . 5 m i c r o f a r a d c on d e ns e r u s e d i n t h e s e e x p e r im e n t st o g e t h e r w i t h t h e i n d u c t a n ce o f t h e l e a d s g av e t h ec i r c u i t a n a t u r a l f r e q u e n cy o f a b o ut 87 k i l o c y c l e s .

d e s c r i p t i o n of t h e p ho to gr ap hs a t t a c h e di s given be low

E i g . 2 3 an d i l l u s t r a t e s i l h o u e t t ep h o to g r ap h s of C a l i b e r .30 b a l l a mm un it io n s e r v i c ev e l o c i t y i n f l i g h t d u r i n g pe n e t r 9 t i o n and. e . f t e r pen e-t r a t i n g s n e i g h t e e n g au g e alu minu m s h e e t . T he se p h o to -g r a p h s i l l u s t r a t e s cu nd waves p r o p o g s t e d fro m t h eb u l l e t i n f l i g h t and as t he y a r e r e f l e c t e d f rom t h eb ac k s i d e o f t h e p l a t e e n d t h e s t a r t of t h e new wa.veas t h e b u l l e t p i e r c e s t h e p l a t e . T hese p h ot o gr ap h s


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were t ~ k e n b ou t 1 0 f e e t i n f r o n t o f t he muzzleof t h e r i f l e and t h e c r y s t ~ l R S p l ~ c e d b ou t twoo r t h r e e f e e t b eyond t h e p o i n t a t Which t h e b u l l e tw s p h o t o g r s p h e d .

F i g u r e s 5 , 6 , 7 , 8 , 9 , 1 0 , a nd 1 2 ,snow m.n i n t e r e s t i n g s e r i e s o f p h o t o g r ~ p h sof C 8 1 . 30-4rnor P i e r c i n g s e r v i c e v e l o c i t y b u l l e t i n v a r i o u s s t R g e sof i m p ~ c t n h ea t t r e ~ t e d om ogeneous one h ~ . l f n c hArmor p l r t e ~ . t d i s t a n c e o f one -hundred yz r ds . Thea pp ro ac h of t n e b u l l e t t o p l a t e i s shown i n F i gu re s5 2nd 6 A t t h e i m m e d i ~ . t emoment of conta.ct ofb u l l e t on p l a t e , f l a r e s p r o b ~ . b lyo f i n c a n d e s c e n tl e a d p p - r t i c l e s a r e e v i d e n t , s e e F ig u r e 7. On f u r t h e rp e n e t r a t i o n of p l n t e t n e j a c k e t m e t a l a p p a r e n t l y p e e l so f f a n d i s t h r u s t forw?.rd on p l ~ t e , e e F i g ur e s 8 and 3.L 2t er s t r g e s of i m p ~ c t f t n e b u l l e t s r e i l l u s t r a t e di n F i z ur e s 1 0 , ~ . n d 2 i n which p m t i c l e s of j w k e tme t a l z nd 1ep.d s p l a s h a r e blo wn f ro m t h e a r e a o f i mp ac t .U nf or tu na te ly t h e ~ c t u p . 1 e n e t r ~ . t i o n f t h e p l l t e i smasked by f l y i n g p a . r t i c l e s d ~ ~ r i n gh e i mp a c t .

P h o t o g r a p h s t a k e n on t h e bac k s i d e of t h ep l a t e b e f o r e , d u r i n g , a nd 5 f t e r im pa ct a r e shown i nF i g u r e s 13 1 4 , 1 5 , 1 6 , 1 7 and 18. S p a l l s a ndi nc sn d es ce n t p ~ . r t i c l e s r e sho~vn l y i n g o f f t h e


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p l a t e i n F i gu r e 1 4. F r o g re s s of b u l l e t p e n e t r a t i o no f t h e r e a r f a n e of t h e p l ~ t e .re i l l u s t r a t e d i nF i g u r e s 17 and 18

s t u d y o f F i g u r e 2 0 shows s l i g h t b u l g i n go f m e t a l w i t h i n a r e a m wk ed ) d u r i n g e a r l y s t a q e so f i m pa c t. A f t e r p e n e t r a t i o n hobrever, t h e a c t u a li m p ac t , F i g u re 2 1, a c t u e l l y o c c u r re d 0.5 i n c h e s f r o mt h i s b u l g e. T hi g o b s e r v a t i o n i s i m p o r t ~ n t n t h es t ud y of o cc ur re nc e of e l ~ s t i c e fo rm at io n d u r i ng t h ee a r l y s t a g e s o f b u l l e t i m p ~ c t .

An a t t e m p t was made t o s t u d y t h e f l o ~ fm e t a l a f t e r b u l l e t i mp ac t on p r e v i o u s l y p o l i s h e d a.ndr u l e d back f ~ c e f a p l e t e . The d i s t o r t i o n c f t h el i n e s n e a r t h e im pa ct i s not p ronounced as shown i nF i g u r e s 2 2 , 2 3 , and 24.

2 . g a c ro an d M i c r o s c o ~ i cExamina t ions h o r t d i s cu s s i o n of macro ~ n d icro-

s c o p i c s t u d y 0f t h e mechanism o f p e n e t r ~ t i o n fa rmor p l a t e t e s t e d a t Aberdeen P ro vi ng Ground i si n c lu d ed i n t h i s r e p o r t as f o l l o w s :

I t h ~ seen o b s er ve d r e c e n t l y t h a t i n p l a t e sof t h e s ta . r ,dard chromium-moly~denum vanadium composi-t i o n an d i n o t h e r c o m p o si t i o ns t h a t f1o.r ?nd f a u l t i n gof t h e m et a l o c c u rs i n t h e v i c i n i t y o f b u l l e t i m pa ct ,F i g u r e s 2 5 and 26 . T her e e v i d e n t l y n a s been s u f f i c i e n t


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h e a t g e n e r a t e d by t h e im pa ct of t n e b u l l e t t o c au set h e m e t al n e a r t h e im pact t o f a . u l t o r s l i p al c n gp a t h s o f s l i p of nc p a r t i c u l a r o r i e n t a t i o n . Theses l i p l i n e s o r w hi te l a y e r s a s t h e y appee.r i n t h ep h o to g ra p hs a r e h a r d e r t h a n t h e s u r r o u n d i n g m e t al a nda r e b e l i e ve d t o be m a r t e n s i t i c due t o t h e f a c t t h a tt h e s e p a t h s of s l i p lvere h ea t e d above t h e c r i t i c a lpo i n t o f t he m et31 a nd qu i c k l y c oo l e d by c c ndu c t i ono f h e a t by t h e s u r r o u n d i n g me t a l.

F i g u r e 2 i l l u s t r a t e s t h e f l o ~ f m e t a ln e a r t h e s u r f a c e o f a rm or p l a t e a t a r e a o f i m pa ct .T h is s t r u c t u r e v a s r e v e a l e d a b ou t 1 inch bel91v thea c t u a l s u r f ac e o f t h e p l a t e . E v id e nt ly t h e b u l l e ti n t he e a r l y s t a ge s o f impact may be compared t c ah i c h s p ee d b o r i n g ma ch in e t h e h e a t a t t im e c f i m pa ctb e i n g s u f f i c i e n t t o c a u s e t o r s i o n a l flo1.1 o f m e t al .In many ca se s s p a l l s yllhich a r e b lown o f f t h e r e a rf a c e o f ar mor : l a t e shovr e v i de nc e c h a r a c t e r i s t i c o ft o r s i o n a l f l o w .

One of t he se sp a . l l s was examined under themicroscope and t was found t h a t t y p i c a l t o r s i o n a ldefo rmat ion 1\las pr es en t .

r e a r f a c e of a p e n e t r a t e d armor p l a t eshoxvn i n Fi g u r e 2 9 i s an example of s p a l l s b lowno f f i n a s c i r a l f o r m ~ . t i o n h i s i l l u s t r a t i o n b e i n gs ug ge s t i ve o f t o r s i ona . 1 i mpac t.


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A n ot h e r c a s e o f r u p t u r e c a u s ed by b u l l e timpp-ct a n d p o s s i b l y by t o r a i o n a l floy:r o f r n e t ~ l sshown i n F i g u r e 28 T h i s r u c t u r e sno ?rs a c t u a l v o i d s ,( b l a c k ) i n t h e f orm o f v il d e f i n e d t ~ i s t s .

3 Sp ec t r og ra ph ic A na ly s i s o f De pos i t f rom L311llet Impact .1 A n pl y si s o f m e t a l l i c p a r t i c l e s r ea ov ed f rom

d e p o s i t , C u , P-J Zn2 . A n a l y s i s o gray po i~ rde r Cu Pb, Fe, .41,

ZrP Nn, C r .The a n a l y s i s i n d i c a t e d t h 2 t l e a d was t h e m e t a l

i n e x ce ss i n t h e d e p o s i t .

R e s p e c t f u l l y s u b m i t t e d ,

R e s e ar c h Met ~ l l u r g i s


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dilhouette photograph o C l . 30ba l l eervioe veloc i ty mun i t i o n i n f l i gh t


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FiEure 3SilhoueGte photograph of Cal 30 ballservioe velocity munition penetrating an 18 geugaluminum sheet


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Sihlouette photograph of Cal 30servioe velocity ammunition after penetrating


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F i k ~ r r Photogre.ph by r e f l e c t e dCal. .30 Armor P i e r c i ng Service Veloci tyb u l l e t n f l i g h t ( s t r i k i n g d i s t m c e100 yards

Figure 6 Photogra.ph by r e f l e c t e d l i g h t ofCal. .30 Armor Piercing ServiceV e l oc i t y bu l l e t n f l i g h t J u e t about t os t r i k e Armor P l a t e . S t r i k i n g d i s t an ce100 yards.


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F ig ure P ho to grnp h by r e f l e c t e d l i g h t o fC e l i b e r 30 Arm o r P ie r c in g S e rv i c e Ve lo c i ty b u l l e t8 t t h e i n s t a n t of s t r i k i n f f Armor P l a t e . Note f l a r e sp r o b ~ b l y urning lead . s t r i k i n g d i s t a n c e 100 y e rd s

Figure 8 Photograph by r e f l e c t e d l i g h t ofC a l i b e r .30 Armor P i e r c i n g S e rv ic e Veloc i tyb u l l e t J u s t s t r i k i n g Armor P l a t e . Note p e e l i n go f f jacrket meta l from b u l l e t core . s t r i k i n gdistance OO y a r d s ) .


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F i g L photogrt rePlecteS l i g h t ofC ~ l Z b e r 30 mop ~ i ' e r c se rv i c6 v e lo c i tyb u l l e t i n progress of ~ C ~ a . t i o nf Amor P l e t e(e t r i k in g d is tance 100 yards.

I r

Figure O Photogrwgb by rsfgeated l i g h t o fCa1..30 Armr PieroWg s e r v i c e v e lo c i ty b u l l e ti n progeese of pene t ra t ing Armor Pl~te.N 068 l jf a p l ~ hnd p a r t i c l e s o J ~ O k e tmetalb@ .ri:gI'mn fiiom impaat. ( s t r i k i n g isaace31 y ~ r d s ) .


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Figure Photogreph by r e f l e c t e d l i g h t ofCa l ibe r 30 Armor P i e r c i n g s e r v i c e v e l o c i t y b u l l e tn progresa of p e n e t r e t i n g Armor P 1 ~ t ; e . Strikingd i s t a n c e - 100 y ~ r d s .

Figure 12 Pf ia tograph by re f lec ted l ight ofC&Lib@ 30 haor P l r c i n g semrtoe v e l o c i t ybun,et; sn pmi &pse~.e:f pqnetraCIng Armor P l a t e ,(str h;ng&i(lt&;na,e 1.00 y~rirds .


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rlgure 3 Back f ~ c e efore lmpect

F m e 4 Rak f ~ c euuring lnt stsgeof i m p~c t . S p a l l s f l y i n g o f f ~ n dlncandeeoent g ~ r t i o l e a


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Fig 1 5 Back f ce after imppot Photogr~phat ken by r e f l e c t e d l i g h t Ammunition C ~ l i b e r 30Armor P i e r c i ng s e r v i c e v e l b c i t y at a d i s t ~ n c eof100 yards

mBigure 6 aak fmce before impaot


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F i g u r e I? Bnck fnce during imppotNose o b u l l e t c o r e a p p e ar i ng t hr o ug hback o p l ~ t e

F i g u r e 18 aAck f a c e of p l a t e Fr~ gmentsbloton o f f P h o t o g r ~ p h e nken by r e f l e c t e d lightAmmunition C d i b e r 30 Armor P i e r c i n g s e r v i c e9 e l o c i t y a t d i s t e n o e o 100 yards


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Figure 1 9 - Back face before impnct

BRCK faceFigure 2 During early stnges of impnctNote crack appearing


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Figure 21 Back f ace a f t e r impactPho tog r~ph aken by r e f l e c t e a l igh tAmmunition Col iber 30 Armor P i e r c i ng semioeve loc i t y at a istmee o 1 y8 rde.

igure 22 Pol ished ru l ed reRr faoe b f o r eiUlp~Ct


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Figure 2 3 Polished r u l ed r en r foceduring r stage of impact.

F i g u ~ e 4 Pol &ed ruled re r facea f t e r & m o t .?tto ogr:&phsD d bg r fleoted l iqbt.Ar&mnft on CBT SQ Armor Pierolngfbo* s.egon&e +aboaX y ,at ?l.al Far.~ef 1 a ..


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X arosCruchole. Ctched


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Rlmlre 7 Kacro structure bullet hole;Qplane ar~.llel to surface. Complete penetration.C , 5 1 8 Cr 1.21 ; MQ 566; \m. -20 ;Etched in Roeenhain-Houghtonis reagent X3

Figure 98 Wibiero structure n e w bottom ofbulLet hole. Arrow indic~.tes ullet penet~ation..426; N1 3 58; Si 2. Ql. Partial penetretion.tshed n 608ium PicPete X lOOO


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Documents

Photographic Study of Impact of Ball and AP on Armor Plate