Transcript 1. Philip B. Magtaan, Reg. Crim., MS Crim 2. Ballistics Chapter
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Transcript 1. Philip B. Magtaan, Reg. Crim., MS Crim 2. Ballistics Chapter 1 3. DEFINITION OF BALLISTICS • In its broadest sense, ballistics is defined as is the science dealing with the motion of projectiles and the conditions governing that motion. Science is a systematized body of knowledge which has been observed tested and proven. Motion refers to movement or mobility. • 3 Types of Motion • Direct motion – is the forward movement of the bullet or shots out of the shell by the action of the expansive force of gases from a burning gun powder. • Gyroscopic motion – is the action of the bullet passing through a rifled bore barrel firearm which is either twisted to the left or right. • Translational – is the action of the bullet once it hits a target and subsequently ricocheted. 4. • Projectile means to metallic and non-metallic object propelled by means of force. In strict sense, it is the study of natural laws relating to the performance of gunpowder and projectiles in firearms and the means of predicting such performance. It is also refers to the science of firearms identification which involves the scientific examination of ballistics exhibits (fired bullets, fired shells, firearms and allied matters) used in crimes involving scientific equipments such as bullet recovery box, bullet comparison microscope and others. 5. ETYMOLOGY • The term ballistics was derived from the Greek word “ballo” or “ballein” which literally means “to throw”. Its root word was also said to have been derived from the name of an early Roman war machine called “ballista” - a gigantic bow or catapult which was used to hurl missiles or large objects such as stones at a particular distance to deter enemy forces. The term ballistics is frequently used synonymously in the press and in police parlance to firearm identification and investigation. 6. BALLISTICS AS A SCIENCE • Ballistics is classified, formulated and verifiable knowledge gathered by observation, research and experiment and based on scientific theory and using scientific equipment and apparatus. Results of firearms identification is an exact science because it permits an absolute precision in results free from possibility of error normal to human perception. Therefore, ballistics per se is not an exact science rather it is a branch of physics or applied science which is subject to changes and development depending upon the demands of the modern civilization. 7. EARLY RECORDED FIREARMS IDENTIFICATION • The earliest recorded identification of firearms by the trained observer was recorded in the criminal investigation by Hans Gross, the great Austrian Criminologist and considered as the father of criminalistics. This refers to the French bullet fired by soldier of Napoleon Bonaparte’s Army, which lodge behind the eye of his grandfather in 1799. The bullet was recovered in 1845 after the death of his grandfather. When Hans Gross saw it, he observed and found out that it was still with traces of gunpowder and this would prove evidentiary value. • Another was done by Charles Waite in the United States of America. He was an employee of New York State who conducted an investigation involving firearms. In 1915, a farmer was accused of murder with a gun. Waite was not convinced by the evidence of the firearms’ experts, and his effort showed that the accused is innocent. Through Waite’s effort, to trace the gun from which the bullet was fired, consequently identify the manufacturer of the gun. 8. • Alexandre Lacassagne (1844-1921)- was the first to recognize the significance of the striations etched found on a bullet extracted from a murder victim and its to link to the gun from which it was fired, thus beginning the science of ballistics. • Edmond Locard (1877-1966) – established the first forensic laboratory in France. His principles “objects or surfaces which came into contact always exchange trace evidence”. • Col. Calvin H Goddard (1920) – pioneered the introduction of science of Ballistics in the different universities in U.S., subsequently it was universally practiced and accepted in the different courts throughout the world. 9. FORENSIC BALLISTICS • Forensic – a term originated from the Latin word “forum”, meaning “marketplace where people gather for public disputation or public discussion”. • Forensic Ballistics – it refers to the science of investigation and identification of firearms and ammunition used in crimes. • It is a refined Tool Mark Identification where the firearm is made of a material harder than the ammunition components, acts as a tool to leave impressed or striated marks on the various ammunition components that come into contact with the harder surface of the firearm. • Dr. Albert Llewellyn Hall, the pioneer in the field in forensic ballistics, was an expert in identifying firearm from the fired bullets. Identification of the crime gun is in the principal purpose and objectives of criminal investigation, to establish the identity of criminal offender and assist in their prosecution. 10. BRANCHES OF BALLISTICS • 1. Interior (internal) Ballistics • It refers to the properties and attributes of the projectile while still inside the gun. It covers from the time; the firearm is loaded with the cartridge, the explosion and the movement of the bullet from the breech to the muzzle of the gun. 11. ATTRIBUTES OF INTERIOR BALLISTICS • Firing pin hitting the primer • In order that the primer should explode, the firing pin should hit such. This is due to the theory of friction wherein there is a resistance to motion created by the firing pin. • Ignition of the priming mixture • Priming mixture is made up of very sensitive material that is commonly located in the center portion of the cartridge case. In order to ignite the priming mixture, it must be live and potent and must be devoid of any moisture. • Combustion of the gunpowder • As the primer crushed and ignited, the flash passes through the vent towards the gunpowder that provides the combustion of gunpowder. 12. • Expansion of the heated gas • There will be equal expansion of heated gas inside the cartridge, after the combustion of gunpowder. The gas expanded in the different direction that tends the bullet and shell to separate from each other in the cartridge. • Pressure developed • When the heated gas created by the burning powder charge is developed, a tremendous pressure is produced in the chamber of the firearm. • Energy generated • Energy refers to the fatal equivalent of a bullet compared to a pound that is drops from a certain height. 13. • Recoil of the gun • The recoil of the gun is due to the Newton’s third law of motion (law of interaction) which states that in every action is always equal and opposite reaction. The forward movement of the bullet after the explosion results to backward movement of the cartridge case. Recoil of the gun is affected by several things such as tightness with which the firearm is held, height of the bore above the center of the stock line of wrist for pistols, shape and design of the butt plate or the pistol’s grip, weight of the firearm and the physical and mental condition of the shooter. 14. • Velocity of the bullet in the gun • The bullet will travel the bore of the barrel depending on the powder load of the cartridges, since it is the powder load that will propel the bullet in the bore of the barrel of the firearm. • Rotation of the bullet in the barrel • When the bullet is driven by the heated gas by tremendous pressure towards the muzzle end, the bullet will rotate following the riflings inside the gun barrel. But if the firearm does not have riflings inside the barrel, the bullet (shot) would just move forward without rotating inside the bore of the barrel until the bullet left the gun muzzle. 15. • Engraving of the cylindrical surface of the bullet • The riflings starting from the breech end up to the muzzle end of the barrel will engraved in the body of the bullet, depending on the number of lands and grooves as part of the class characteristics of the firearm. 16. 2. EXTERIOR (EXTERNAL) BALLISTICS • It refers to the attributes and movements of the bullet after it has left the gun muzzle, which includes the condition of the bullets’ movement and flight up to the target. 17. ATTRIBUTES OF EXTERIOR BALLISTICS • Muzzle blast – it is the noise created at the muzzle point due to sudden escape of the expanding gas coming in contact with the surrounding atmosphere. Due to this sound at the muzzle end of the gun, a silencer was invented to minimize the sound, which the criminal took advantage to conceal the crime. • Muzzle energy – it is an energy generated at the muzzle point, whenever the cartridge explodes from a firearm. • Trajectory – actual curve path of the bullet during its flight from the gun muzzle to the target. There are three stages of trajectory namely, straight horizontal line, parabola like flight and vertical drop. 18. • Range – straight distance from the muzzle to the target. It is classified into: 1. Accurate /maximum effective range – it is the distance within a shooter has control of his shots. 2. Absolute maximum range – it is the farthest distance that a projectile can be propelled from a firearm. It is based upon the intrinsic accuracy of the firearm and ammunition, size of the target, marksmanship ability of the shooter, the ability to discern the target, knowledge of the ballistics characteristics of the ammunition, and the level of power needed to be delivered to the target. • Velocity – rate of speed per unit time. 19. • Air resistance/aerodynamic drag – resistance encountered by the bullet during its flight which reduces its speed. There are three parts of drag bullet, the bow resistance, skin friction and the base drag.