Investigation of Forensic Glass Fractography made by Different Ammunition

Research Article

Austin J Forensic Sci Criminol. 2015; 2(5): 1045.

Investigation of Forensic Glass Fractography made by Different Ammunition

Waghmare NP*, Lal A, Sahu K and Anand VR

Central Forensic Science Laboratory, Bureau of Police Research and Development, India

*Corresponding author: Narayan P Waghmare, Central Forensic Science Laboratory, Bureau of Police Research and Development, MHA, Government of India, 30 Gorachand Road, Kolkata-700014, India

Received: February 17, 2016; Accepted: May 10, 2016; Published: May 12, 2016


At the scene of crime, investigating officer/crime scene manager or forensic glass examiner often encounters the shooting at inanimate target such as glass, door, window panes, windows of an automobile etc. Now a day, window panes are coated with transparent, but colored sun control coated film for fancy purpose as well as to maintain inside privacy in the houses/offices or in an automobile. These films are easily available in the open market. The main aim of this experiment is to study the fracture characteristics of sun control coated film on various thickness of windowpane by using regular jacketed, non-jacketed and semi jacketed ammunitions manufactured in an Indian Ordnance factory, India. The film-coated window panes were kept at front and away from the muzzle end.

The experimental findings of types of bullets on sun control coated film windowpane were completely different. At the crime spot, investigating officers may confuse if the actual shooting took place through film coated glass panes and simulation of crime scenes are not correctly carried out in the laboratory. The detailed findings of this fractography study of the sun control coated film windowpane by .315”, AK-47, .303” rifles and 9 mm regular and country made pistol may be efficacious to forensic community.

Keywords: Crime scenes; Ammunition; Rifle; Sun control coated films; Glass fractography


In criminal investigation, it is well known fact that, intermediate targets may influence the distribution of the projectile fragments in case of fatal injuries by regular rifles. A variety of objects like glass, ceramics, window screens, vehicles, walls and articles of clothing, served as intermediate targets for bullet may cause ricochet bullet or it may become secondary missiles.

In literature, various methods are available for examination and comparison of glass fragments. The variations in size of glass sheet have a significant influence on the resultant fracture described by [1- 3] estimated remaining velocity of bullets fired through glass plates [4]. Interpreted the mode of glass fracture arise by bullet impact, in terms of dynamical stress field [5]. Observed that the perforation craters produced on glass had always a well defined shape with more or less constant semi angle which were independence of the projectile caliber, velocity and thickness of the target. Hackle marks are also found on the roughened surface surrounding the fracture hole. A small arms bullet is Cylindroconical in shape and endowed with a high rate of spin. When such bullet traverses through a glass target it makes considerable difference and modifies the basic values of various parameters as reported by [6-7]. The implications of forensic problems of the manner in which a flat glass surface break was described by [8-9] laboratory followed their reports of evidence of fractured glass in criminal investigation [10]. Described examination of glass fracture from a forensic point of view. A detailed discussion on the nature of glass fracture as an aid in the solution of forensic issues was described by [11]. Engineering aspect of glass fracture was reviewed by [12-13].

No studies were reported on fracture of sun control coated thin film window pane in forensic point of view. In this paper attempts were made to analyse the fracture of glass of sun control coated thin film windowpane as target fired by .315 rifles, 303 rifle, AK47 rifle, 9mm pistol and an improvised pistol using their respective ammunitions and compared their result for collaborative analysis. This study will help forensic examiners ascertain the nature of glass fragmented.

Method and Materials

A specially designed metal frame was used to fix the 1 feet x 1 feet sun control coated thin film windowpane. The proposed frame was kept perpendicular to the muzzle end of the weapons. Initial and remaining velocities of each firearm were measured by using electronic timers developed by Electric Corporation of India Limited, Hyderabad (Table 1). The arrangement of firing is shown in Figure 1. The test firings are done as per Table 1, 2, 3. The data as shown in Table 1, .315” sporting rifle, .303” rifle, Ak-47 rifle, 9 mm semiautomatic pistol and country made pistol with a combination of 8 mm (soft nose bullet), .303” (fully jacketed bullet), 7.62x39 mm (fully jacketed bullet), 9 mm (fully jacketed bullet) and 8 mm (soft nose bullet) respectively, were fired and simultaneously their muzzle (initial) and remaining velocity of each firearm were measured. The details are shown in Table 2 and 3. The detailed fractured characteristics present on glass sheet produced by each firearm have been briefed in Table 4 and 5.