THE ASSOCIATION OF INTERMEDIATE TARGET AND TERMINAL BALLISTICS AS EVALUATED BY A 5.56 MM BULLET

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1 1 INTERNATIONAL JOURNAL OF APPLIED BIOMEDICAL ENGINEERING VOL.11, NO THE ASSOCIATION OF INTERMEDIATE TARGET AND TERMINAL BALLISTICS AS EVALUATED BY A 5.56 MM BULLET Nithanthaya Klungploy 1,2, Kittisak Yakoompai 3, Amporn Charuchinda 3, Chalongkwan Tangbanluekal 1, Pitak Thumwarin 4 and Charkriya Promsuban 5,* 1 Department of Forensic Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Thailand 2 Sub-Division of Firearms and Ammunition Identification, Police Forensic Science Center 6, Office of Forensic Science Police, Royal Thai Police, Thailand 3 Sub-Division of Firearms and Ammunition Identification, Division of Central Scientific Crime Detection, Office of Forensic Science Police, Royal Thai Police, Thailand 4 Department of Computer Engineering, King Mongkut s Institute of Technology Ladkrabang, Thailand 5 Department of Anatomy, Faculty of Medical Science, Naresuan University, Thailand ABSTRACT In political unrest situations of Thailand, an M-16 assault rifle with a 5.56 mm bullet firing through vehicle tend to be more intense. Damages caused destruction in life, asset and also national security. This study aimed to investigate the involvement between intermediate targets and terminal ballistics from a 5.56 mm bullet in terms of wound characteristics and bullet fragmentation pattern changing from human tissue simulant after impact. The firing model was performed by M-16A1 assault rifle together with 5.56 mm bullet (M193) which was priory fired penetrate through intermediate targets (metal sheetand glass sheet-intermediate target firing conditions) or directly impact to human tissue simulant (soap block) as non-intermediate target firing condition in 50 m firing distance. The factors affecting intermediate targets such as wound channel characteristic including entrance hole, initial upset depth, temporary cavity, and penetration depth showed statistically significant difference between non-intermediate target and intermediate targets firing conditions. The bullet fragmentation pattern also showed a significant difference in forensic evidence. Keywords: M16, M193, terminal ballistics, intermediate target, bullet fragmentation 1. INTRODUCTION To date, the trend of using M-16 assault rifle on sedition has been found in Bangkok and three southern border provinces in Thailand. M-16 assault rifle power was designed to propel 5.56 mm bullets with the immense power. This can travel to the object particularly auto parts such as car glass and car door and also target body via 3,250 ft/s in maximum velocity causing grave danger on country subsistence and social security [1]. Manuscript received on Mar 20, 2018; revised on May 03, * Corresponding author E mail: charkriyap@nu.ac.th Department of Anatomy, Faculty of Medical Science, Naresuan University, Thailand In case of human tissue simulants firing, the specific bullet fragmentation characteristic called lead snowstorm was only performed with conflicted target via high velocity and less mass bullets especially 5.56 mm bullet firing cases. The white delicate fragments in X-ray films dispersed within target area body that resemble with dust or snowstorm characteristic [2-4]. This wound characteristic, lead snowstorm whether refer to the effect of 5.56 mm bullet (M193) fragmentation pattern from M-16A1 assault rifle penetrate through various intermediate targets including metal sheet and glass sheet or non-intermediate target, impact to human tissue simulant in 50 m of firing distance did not find out. The association of specific bullet fragmentation patterns and impacted human tissue simulant characteristics in various intermediate targets were studied for the advantage of evaluating the criminal circumstance from the disturbance created by M-16A1 assault rifle together with 5.56 mm bullet (M193). 2. MATERIALS AND METHODS 2.1 Terminal ballistics determination Fifteen 5.56x45 mm bullets (M193) 6 th product lot of Fábrica Nacional de Munições de Armas Ligeiras, Chelas, Portugal (FNM) in 1986 were shot using M-16A1 assault rifle of COLT brand into 15 human tissue simulants which divided into 3 various firing conditions including non-intermediate target, metal sheetintermediate target, and glass sheet-intermediate target. Fifteen soap blocks, human tissue simulants were made from translucent glycerine with base size of 18x18x30 cm for each 5 firing conditions. Five metal sheets, car door auto parts were obtained from the door of Toyota pick-up car, model Hilux Vigo with size of 18x18 cm for metal sheet-intermediate target firing condition. Five tempered glass sheets, car glass auto parts were obtained from the front car glass with tinted window film covering with size 18x18 cm and 6 mm thickness for glass sheet-intermediate target firing condition.

2 N. Klungploy et al. 2 Entrance hole height, initial upset depth, temporary cavity height and penetration depth were measured and taking photo with scale. Dispersed bullet fragmentations in soap blocks were collected. The difference in vary intermediate targets firing as terminal ballistics determination were compared. (A) 2.2 Statistical analysis GraphPad Prism version 6 was used for statistical analysis. The values of wound ballistics were compared by one-way ANOVA method. The data in each experiment were calculated using mean ± SD. A p-value of < 0.05 was considered significant. (B) 3. RESULTS 3.1. Characteristics of fired human tissue simulants Similar to a wound channel found in a shot body, this experiment used a 5.56 mm bullet (M193) firing into human tissue simulant, soap block. The wound channel results obviously found different characteristics in various intermediate targets which presented the enhance hole defining soap block surface that bullet impacted (Figure 1). The first period that bullet impact and travel through the soap block called initial upset depth. Then bullet transfer the large amount of energy through soap block leading to large channel performance as called the temporary cavity. After that the bullet and its fragment traveled along the soap block until the end of energy, prior to bullet stopped which the total distance of bullet direction in soap block was called penetration depth (Figure 2). According to the various firing conditions, entrance hole, initial upset depth, temporary cavity, and penetration depth were significantly different (Figure 3). (C) Figure 2. Wound channel characteristics in different intermediate target firing conditions at 50 m firing distance: (A) non-intermediate target firing, (B) metal sheet-intermediate target firing, (C) glass sheetintermediate target firing. Note: (1) initial upset depth, (2) temporary cavity, and (3) penetration depth Entrance hole The entrance hole was measured from the surface of human tissue simulants that bullet impacted. Glass sheetintermediate target firing condition showed the significant difference at p-value < 0.05 when compared to non-intermediate target and metal sheet-intermediate target firing conditions. But there was no significant difference between non-intermediate target and metal sheet-intermediate target firing conditions (Figure 1 and 3). (A) (B) (C) Figure 1. Entrance hole of wound channel in different firing conditions at 50 m firing distance: (A) nonintermediate target firing, (B) metal sheet-intermediate target firing, (C) glass sheet-intermediate target firing. Figure 3. Comparison of wound channel characteristics in different intermediate target firing conditions at 50 m firing distance (n=5 each group). * and # indicate p-value < 0.05 compared with non-intermediate target and metal sheet-intermediate target firing conditions, respectively.

3 3 INTERNATIONAL JOURNAL OF APPLIED BIOMEDICAL ENGINEERING VOL.11, NO Initial upset depth The initial upset depth was measured from human tissue simulants in the first period that bullet impact and travel through the soap block. Metal sheet-intermediate target firing condition showed the significant difference at p-value < 0.05 when compared to non-intermediate target firing condition. However, the result in glass sheet-intermediate target firing condition was not able to measure due to a deformation of bullet since the penetration through the glass sheet. Many bullet cluster piece dispersed upon impact soap block and initial upset depth could not be determined (Figure 2 and 3). (A) (C) (B) Temporary cavity The temporary cavity was measured from human tissue simulants when bullet transfers large amount of energy through soap block leading to large channel performance. Glass sheet-intermediate target firing condition showed the significant difference at p-value < 0.05 when compared to non-intermediate target firing condition. But there was no significant difference between non-intermediate target and metal sheetintermediate target firing conditions (Figure 2 and 3) Penetration depth The penetration depth was measured from human tissue simulants when bullet and its fragment traveled along the soap block until the end of energy, prior to bullet stopped. Glass sheet-intermediate target firing condition showed the significant difference at p-value < 0.05 when compared to non-intermediate target and metal sheet-intermediate target firing conditions. But there were no significant difference between non-intermediate target and metal sheet-intermediate target firing conditions (Figure 2 and 3) Bullet fragmentation pattern Bullet fragmentation was found within wound channel created by 5.56 mm bullet shot at high velocity with less mass. In different intermediate targets firing found the variation of bullet fragmentation pattern related to the characteristic of fired human tissue simulants which showed the significant difference in comparison between non-intermediate target and both metal sheet- and glass sheet-intermediate target firing conditions at 50 m firing distance (Figure 4). Figure 4. The bullet fragments in different intermediate target firing conditions at 50 m firing distance (n=5 each group): (A) non-intermediate target firing, (B) metal sheet-intermediate target firing, (C) glass sheetintermediate target firing. 4. DISCUSSION At 50 m firing distance by M-16A1 assault rifle together with 5.56 mm bullet (M193), the terminal ballistics including characteristics of fired human tissue simulants and bullet fragmentation pattern showed the statistically significant difference between nonintermediate target and both metal sheet- and glass sheetintermediate target firing conditions. In term of the bullet fragmentation patterns in nonintermediate target firing, the collected bullet found the cannelure break off with only kidney-shaped of the bullet base. But the tip of bullet had already fallen out and/or penetrated through the human tissue simulant. In metal sheet-intermediate target firing, the collected bullet also showed the cannelure break off with only the tearing of the jacket but not as much as the full tearing between the bullet tip and base. The collected bullet in this condition showed the at most perfect characteristic due to the less bullet velocity from the kinetic energy transferring to the metal sheet during the bullet impact to soap block period. The less impact power to soap block leaded to the less of soap block resistance power with affecting the bullet. Therefore, the less bullet deformation of metal sheet-intermediate target appeared when compared to non-intermediate target condition. For non-difference of penetration depth when compared to non-intermediate target condition, the reason was due to the depth of the soap block that performed only 30 cm. This affected to the present study limitation which could not measure the distance after the bullets or bullet fragments penetrated through the soap block. The obvious different finding in soap block of metal sheetintermediate target firing condition was the small holes dispersed around the entrance hole from the bullet fragments. The impact power accompanying with the partial of kinetic energy transferred from the bullet to the

4 N. Klungploy et al. 4 metal sheet during the penetrated period, which caused the evert and fracture of the lead within the bullet base. After the bullet penetrated through the metal sheet, the small pieces of bullet and metal sheet fragments moved to the soap block in the expanded cone-shaped appearance with non-definite direction. The fragments had less mass leading to the small distance within the soap block during impact and penetration period. The finding of dispersed small holes around entrance hole was the special characteristic that only been found in metal sheetintermediate target but not in non-intermediate target condition [5]. In the case of perfect bullet shape or bullet tip collection, the obvious difference at the end of tip was found. In non-intermediate target firing condition, the end of tip showed the spiked characteristic as non-fired bullet. But in metal sheet-intermediate target condition, the end of tip obviously showed the blunt characteristic due to the metal sheet impact according to the dense material appearance of metal sheet. Moreover, the entrance hole of non-intermediate target condition had the circle characteristic. Nevertheless, the entrance hole of metal sheet-intermediate target condition showed the ellipse characteristic. This finding supported the theory that the increasing of angle of incidence were from the losing of bullet gyrostatic moment due to the dense material impact. The increasing of angle of incidence caused the bullet impact to soap block in the gradual less perpendicular appearance when the angle increased [6]. Therefore, the ellipse entrance hole characteristic in metal sheet-intermediate target firing was shown. In glass sheet-intermediate target firing, the result showed the obvious difference in aspect of the entrance hole when compared to the non-intermediate target condition. The bullet deformed and fragmented since the period that bullet penetrated through glass sheet resulting in the larger size of entrance hole as 7.63 times when compared to non-intermediate target condition accompanying with many pieces of glass and bullet fragments remaining around the entrance hole [5, 7-9]. This finding continually led to the non-initial upset depth. The result also showed the compact of delicate glass fragments along the bullet direction within the soap block. Moreover, the bullet transferred to the glass sheet which continually performed the rupture line. The glass sheet also received much kinetic energy from the bullet leading to more bullet energy losing. This caused the decreasing of bullet penetration power which affected to the less of penetration depth when compared to nonintermediate target condition [10]. The wound cavity showed the large size, according to the bullet impact power that impact to the glass sheet. This impact power resulted in the bullet deformation and fragmentation into many pieces. The bullet fragments moved toward the soap block in expand cone-shaped characteristic and impacted to the soap block. Then entrance hole and wound cavity interlocked. Another obvious finding was the bullet fragmentation, the result showed the deformation on spike of tip due to the bullet impact to the glass sheet. However, the bullet stability still remained leading to the tip forward position that impact to the soap block resistance. This caused the flatten pack characteristic of the lead within the bullet. The at most lead still remained within the jacket and also found some part fall out into many small pieces with non-deformed finding on cannelure. 5. CONCLUSION The study found different findings in various intermediate target firings with 5.56 mm bullet (M193) in aspect of terminal ballistics including characteristics of wound channel and bullet fragmentation pattern. These associated with the evaluation of possible criminal circumstance from the disturbance created by M-16A1 assault rifle. Further studies regard the characteristic of fired human tissue simulant in different intermediate target firings on X-ray film evaluation which may help to provide the better understanding in lead snowstorm, special characteristic of bullet fragmentation pattern. 6. ACKNOWLEDGEMENTS The authors would like to acknowledge the Firearms and Ammunition Detection Sub-Division, Central Scientific Crime Detection Division, Office of Forensic Science Police and staffs, and also the Praya Surasi Camp Shooting Ranges, Border Patrol Police for experimental facilities supporting. This work was supported by the Siriraj Graduate Thesis Scholarship, Faculty of Medicine Siriraj Hospital, Mahidol University, Thailand. REFERENCES [1] Frank CB. Cartridge of the world: a complete and illustrated reference for over 1500 cartridges. 12nd ed. Wisconsin: Krause; [2] Tsatok T, Eliezer L, Yaron S, Nikolai V, Alan C. Estimating projectile perpendicular impact velocity on metal sheet targets from the shape of the target hole. J Forensic Sci. 2009;54(1): [3] Phillips CD. Emergent radiologic evaluation of the gunshot wound victim. RadiolClin N Am. 1992;30(2): [4] Anthony JW. Gunshot injuries: What does a radiologist need to know?. 1998;19(5): [5] Vincent DM. Gunshot wounds: practical aspects of firearms, ballistics, and forensic techniques. 2nded. New York: CRC; [6] Coupland RM. Wound ballistics and surgery. In: Kneubuehl BP, Coupland RM, Rothschild MA, Thali MJ, editors. Wound ballistics: basics and applications. Berlin: Springer; [7] Donoghue ER, Kalelkar MB, Richmond JM, Teass SS. Atypical gunshot wounds of entrance: an empirical study. J Forensic Sci. 1984; 29: [8] Dixon DS. Tempered plate glass as an intermediate target and its effects on gunshot wound characteristics. J Forensic Sci. 1982; 27: [9] Stahl CJ, Jones SR, Johnson FB, Luke JL. The effect of glass as an intermediate target on bullets: experimental studies and report of a case. J Forensic Sci. 1979; 24:6 17. [10] William HP. The behavior of bullets fired through glass. J. Crim. L. & Criminology. 1939; 29(5):

5 5 INTERNATIONAL JOURNAL OF APPLIED BIOMEDICAL ENGINEERING Pol.Capt. Nithanthaya Klungploy is currently scientist (level 1) in Firearm and Ammunition Identification Sub-Division, Police Forensic Science Center 6, Office of Forensic Science, Royal Thai Police. She received Bachelor of Science in Chemistry and Master of Science in Forensic Science from Mahidol University, Thailand in 2012 and 2016, respectively. She works about firearm and ammunition identification. Her researches focus on comparison of fired projectile evidence. Pol.Col. Kittisak Yakoompai is currently scientist (level 4) in Firearm and Ammunition Identification Sub-Division, Central Scientific Crime Detection Division, Office of Forensic Science, Royal Thai Police. He received Bachelor of Sciences in Physics, Master of Arts in Political Science from Ramkhamhaeng University and Bachelor of Laws from Thammasat University, Thailand in 1996, 2004 and 2011, respectively. He is a chief of Firearm and Ammunition Identification Sub-Division, Central Scientific Crime Detection Division, Office of Forensic Science, Royal Thai Police. He works about firearm and ammunition identification and sub-division management. His researches focus on ballistics and comparison of fired projectile evidence. Pol.Lt.Gen. Amporn Charuchinda is currently retired police (level 10) in Royal Thai Police. He received Bachelor of Science in Physics and Master of Engineering in Nuclear Technology from Chulalongkorn University, Thailand. He used to be Commissioner of Office of Forensic Science and consultant of Commissioner-General, Royal Thai Police. He used to work about firearm and ammunition identification, sub-division and division management in Firearm and Ammunition Identification Sub-Division and Central Scientific Crime Detection Division, Office of Forensic Science, Royal Thai Police, respectively. He is an expert in firearm and ammunition. Asst.Prof.Dr. Chalongkwan Tangbanluekal is currently retired faculty position of Mahidol University. She received Bachelor of Science in Chemistry-Biology from Chulalongkorn University, Master of Science in Forensic Science from Mahidol University, Thailand and Doctor of Philosophy in Toxicology from North Carolina State University, United States of America in 1978, 1981 and 1990, respectively. She was a program director in Master of Science in Forensic Science, Department of Forensic Medicine, Faculty of Medicine, Siriraj Hospital, Mahidol University. Her researches focus on health risk assessment, toxicology and environmental forensics. VOL.11, NO Asst.Prof.Dr. Pitak Thumwarin is currently lecturer in Faculty of Engineering, King Mongkut's Institute of Technology Ladkrabang. He received Bachelor of Science in Applied Physics, Master of Science in Computer Science and Information Technology from King Mongkut's Institute of Technology Ladkrabang, Thailand and Doctor of Engineering in Electrical Engineering from Tokai University, Japan in 1991, 1996 and 2004, respectively. He is program director of Music Engineering and Multimedia, Faculty of Engineering and vice president of King Mongkut s Institute of Technology Ladkrabang. His researches focus on pattern recognition, biometrics, music note score recognition and forensic sound. Dr. Charkriya Promsuban is currently lecturer in Department of Anatomy, Faculty of Medical Science, Naresuan University. She received Bachelor of Applied Thai Traditional Medicine from Burapha University, Master of Science in Anatomy and Doctor of Philosophy in Medical Physiology (International program) from Mahidol University, Thailand in 2010, 2012 and 2017, respectively. She teaches anatomy, physiology, pharmacology and forensic pathology. Her researches focus on neuroscience, herbal medicine, applied Thai traditional medicine, and forensic science.