Forensic Ballistics : A Complete Overview

What is Forensic Ballistics?

Forensic ballistics is the examination of evidence relating to firearms at a crime scene. It studies ballistic speed, mobility, angular movement, and the effects of projectile units such as bullets, missiles, and bombs.

Who is the Father of Forensic Ballistics?

Calvin Hooker Goddard is known as the father of forensic ballistics.

He was a forensic scientist, army officer, academic, researcher, and pioneer in forensic ballistics.

What can ballistics determine?

Forensic ballistics determine:

  • Which type of gun is used by the criminal?
  • Whether the gun is associated with any other crime?
  • The amount of damage a bullet can inflict.
  • Estimate the position of the shooter by analyzing the bullet marks.
  • From which angle was the gun fired?
  • When do they get fired?
  • The type of impact made by the bullet.
  • To reveal the shooter’s identity.
  • Comparison of different firearms, bullets, and cartridge cases.

Who is a Ballistics Expert?

A forensic ballistics expert matches, analyzes and examines bullets, cartridges, fragments, and other evidence with the weapons of alleged suspects or others involved in a case.

The first case of forensic firearm examination

The first case of forensic firearm examination was done and documented in 1835. That was when Henry Herbert Goddard applied ballistic fingerprinting to link a bullet recovered from the victim to the actual culprit. After careful inspection of the bullet, he found that there was a deformation on the surface of the slug that was not because of the barrel or by the impact. It appeared to be a manufacturing defect. He understood that retrieving the shot from the weapon would help him easily confirm the shooter. When the suspect’s house was checked, a mold was found.  the marks on the mold and the mark on the bullet matched completely after comparison. Finally, he confessed his crime.

 Basic Theory Of Firearm Mechanism

The weapon aims to convert chemical energy into kinetic energy to expel a projectile from the firearm.

Firearm Mechanism

The Mechanism is :

A round consists of an outer cartridge case, a bullet, some form of propellant, and a percussion cap is first loaded and locked into the breach.

The firing pin is generally mechanically restrained, and when the firearm is cocked, the firing pin spring is compressed.

As the trigger is pulled, the hammer-mounted firing pin is forced forward to strike through a small hole in the breech face, hitting the primer cup (which contains a mixture of sensitive chemicals), which rapidly burns and produces sufficient hot gases to ignite the propellant.

As the gunpowder is ignited, an expansion of gas occurs, which, confined in a small space, eventually forces the bullet down the barrel of the firearm.

Types Of Ballistics

Internal Ballistics – Internal ballistics are about the motion of the projectile in the bore of the weapon.

External Ballistics – External Ballistic is the Motion of the projectile from the muzzle end of the barrel to the target.

Terminal Ballistics, also known as Wound Ballistics, deals with the effect of a projectile on the target.

Transitional Ballistics– It deals with the projectile’s motion from the time it leaves the muzzle until the pressure behind the projectile is equalized.

Types of Firearm

Revolver— A revolver is a Handgun with a cylinder with holes to contain the cartridges. The cylinder revolves to bring the cartridge into position to be fired.

Rifle— Essentially, a long rifled barrel firearm primarily designed for relatively long-range use in warfare or hunting. Rifles are available as single-shot, self-loading, manual action, bolt action, or automatic, though the most commonly encountered are self-loading.

Submachine Gun – A fast-loading weapon with a high rate of fire, available as single shot or fully automatic. The inaccurate SMG is a magazine-fed weapon which can hold up to around 100 rounds, designed for continuous fire.

Machine Gun— A machine gun is a fully automatic firearm with a very high rate of fire, fast reload time, and great power. It is generally only used by the military.

Shotgun – A shoulder-fired long gun with no rifling in the barrel, designed to shoot a large number of small projectiles (“shot”) rather than a single large projectile (“a bullet”).

Pistols – Pistols are firearms designed for a more automatic operation. Cartridges are loaded into an ammunition magazine which is inserted into the firearm.

Other – Other types include:

  • Air Guns,
  • Gas Guns,
  • Antique Guns,
  • Light Weapons, Etc.

Examination Of Bullets

CLASS CHARACTERISTICS

The make and model of the weapon can also be inferred from the combination of different class characteristics common to specific manufacturers. The three main class characteristics of all bullets are the:

Lands are the raised portions between the grooves inside the barrel after the spiral grooves are cut to produce the rifling.

In firearms, calibre is the specified nominal internal diameter of the barrel.

Rifling twist refers to the rifling in the barrel of modern rifles, making a full 360-degree rotation in a given length of inches.

INDIVIDUAL CHARACTERISTICS

These random imperfections or irregularities can be produced by:

  • Manufacture
  • Wear from Abuse
  • Wear from Use

The striations on the bullet can make identifiable and unique markings that trace it back to a particular firearm.

How Good a Match Is It?

The theory behind firearm identification is that microscopic striations and impressions left on bullets and cartridge cases are unique, reproducible, and, therefore, like “ballistic fingerprints” that can be used to identify a gun. If investigators recover bullets or cartridge cases from a crime scene, forensic examiners can test-fire a suspect’s gun to see if it produces ballistic fingerprints that match the evidence.

Ballistic Fingerprinting – Ballistic fingerprinting refers to a set of forensic techniques that rely on marks that firearms leave on bullets to match a bullet to the gun it was fired with.

THE COMPARISON MICROSCOPE

The comparison microscope is an essential tool for firearm examination.

Two bullets can be observed and compared simultaneously within the same field.

Comparison Microscope
QnA on Forensic Ballistics
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