Type of Bullets | Composition and multiple terms like Caliber and Cartridge.

Bullets, as projectiles fired from firearms, come in a wide range of shapes, sizes, and materials, each tailored to serve specific purposes and applications. The design and construction of bullets are crucial factors in determining their performance, accuracy, and terminal effects on the target. 

FORENSIC SCIENCEFORENSIC BALLISTICS

Shubham Kumar

1/29/20245 min read

Bullets are essential components of firearms ammunition, serving as kinetic projectiles expelled from the muzzle end of the firearm when the trigger is pulled. These small, cylindrical projectiles are responsible for delivering lethal force to a target.

Composition of Bullet

Bullets are typically constructed from various materials, each offering distinct advantages for specific applications. One of the most common materials used in bullet construction is lead. Pure lead is relatively soft, making it easy to shape and mold. However, due to its softness, pure lead bullets tend to deform upon impact, reducing their effectiveness and accuracy. To address this issue, lead is often alloyed with antimony to create harder lead alloys. Antimony significantly improves the bullet's hardness and resistance to deformation, enhancing accuracy and terminal performance.

In addition to lead alloys, bullets can be made from other materials like steel, copper, brass, polymer, rubber, and even wax. Steel bullets are often used in certain military applications due to their armor-piercing capabilities. Copper and brass are commonly used as jacketing materials to encase lead cores, enhancing bullet stability and reducing barrel fouling. Polymer and rubber bullets are used primarily in non-lethal applications, such as riot control and animal deterrence. Wax bullets are used in specialized training scenarios for safety and reduced lethality.

Type of Bullets

Bullets, as projectiles fired from firearms, come in a wide range of shapes, sizes, and materials, each tailored to serve specific purposes and applications. The design and construction of bullets are crucial factors in determining their performance, accuracy, and terminal effects on the target.

Unjacked bullets

Unjacketed bullets, also known as soft lead bullets or plain lead bullets, are projectiles that are not encased in a harder metal jacket. They are primarily made of lead, and sometimes, other metallic components are mixed in to enhance their strength and performance. Unjacketed bullets have unique characteristics that make them suitable for specific applications, including hunting, target shooting, and historical reenactments.

Important characteristics of the unjacked bullets includes the softness of bullet, versatility and lead fouling. Unjacked bullets are soft because they lack the metal casing, therefore, they gets deformed easily when fired. These bullets are versatile in nature, i,e can be easily projected by multiple types of firearms. Since, they lack metal casing, they leaves lead residues in the barrel when fired, which is called lead fouling. Unjacked bullets are mostly used for hunting and target shooting practices.

Jacked Bullets

A jacketed bullet refers to a specific type of ammunition projectile used in firearms. It consists of a lead or lead-alloy core enclosed within a harder metal jacket. The jacket is typically made of copper, although other metals such as gilding metal (a type of brass) can also be used. The purpose of the jacket is to enhance the bullet's performance and improve its accuracy, reliability, and penetration capabilities.

Widely used jacked bullets types are Round-Nose Jacked Bullet and Hollow-Pointed Lead Bullet. Round-Nose Lead Bullets: These are the most common type of unjacketed bullets, featuring a rounded nose design. Round-nose lead bullets are typically used in target shooting and recreational shooting sports due to their cost-effectiveness and ease of casting. Hollow-Point Lead Bullets: Hollow-point bullets have a cavity in the nose that promotes controlled expansion upon impact. This expansion creates a larger wound channel, making hollow-point lead bullets effective for hunting and self-defense applications.

Terms Related to Bullets

Bullet caliber and cartridge are fundamental concepts in firearms and ballistics, playing a crucial role in the safe and accurate functioning of firearms. These concepts are essential for firearm enthusiasts, hunters, law enforcement officers, and anyone interested in understanding the intricacies of firearms and ammunition.

Caliber

The caliber of a bullet refers to its diameter, typically measured in inches or millimeters. It is one of the most critical specifications of a bullet, as it determines how the bullet fits and engages with the firearm's barrel. A proper match between the bullet's caliber and the firearm's barrel chamber is essential for safe and effective firing.

Measurement and Notation

Bullet caliber is measured either in inches (imperial system) or millimeters (metric system). In the imperial system, caliber is denoted by fractions of an inch, such as .22, .38, .45, and .50. The first number indicates the bullet's nominal diameter in hundredths or thousandths of an inch. For example, a .22 caliber bullet has a diameter of approximately 0.22 inches.

In the metric system, the caliber is denoted in millimeters, such as 9mm, 10mm, and 7.62mm. In this notation, the number represents the bullet's actual diameter in millimeters. For instance, a 9mm caliber bullet has a diameter of approximately 9 millimeters.

Common Calibers

Firearms come in various calibers to suit different purposes and applications. Some common bullet calibers include:

  • .22 Caliber: Often used in small caliber rifles and handguns for target shooting, training, and recreational plinking.

  • 9mm Caliber: One of the most popular handgun calibers worldwide, used by military, law enforcement, and civilians for self-defense and target shooting.

  • .45 Caliber: Renowned for its stopping power, this caliber is used in many handguns, particularly in the 1911 platform.

  • .308 Caliber: Commonly used in rifles, especially for hunting and long-range shooting.

Bullet caliber is a crucial consideration when selecting ammunition for a firearm. Using the wrong caliber can lead to dangerous consequences, including damage to the firearm or injury to the shooter.

Cartridge

A cartridge is a complete unit of ammunition that contains all the components necessary for a firearm to fire a bullet. It comprises four main elements: the bullet, casing, propellant (gunpowder), and primer.

Components of a Cartridge
  1. Bullet: The bullet is the projectile or the actual part of the ammunition that is expelled from the firearm's barrel when the trigger is pulled. It is the component responsible for delivering kinetic energy to the target.

  2. Casing: The casing is the container that holds all the other components of the cartridge together. It is typically made of brass, steel, or other metals and plays a crucial role in sealing the chamber to contain the high-pressure gases produced during firing.

  3. Propellant: The propellant, often referred to as gunpowder, is a chemical substance that burns rapidly when ignited by the primer. It generates a high-pressure gas that propels the bullet down the barrel.

  4. Primer: The primer is a small, sensitive explosive compound located at the base of the cartridge casing. When struck by the firing pin, the primer ignites, creating a spark that ignites the propellant and initiates the firing sequence.

Cartridge Types

There are various types of cartridges, each designed for specific applications. Some common cartridge types include:

  • Rimfire Cartridge: In rimfire cartridges, the primer is distributed within the rim of the cartridge base. Rimfire ammunition is relatively inexpensive and is often used for small caliber firearms, such as .22 LR (Long Rifle) rifles and handguns.

  • Centerfire Cartridge: In centerfire cartridges, the primer is located at the center of the cartridge base. Centerfire ammunition is more powerful and versatile than rimfire ammunition, making it suitable for a wide range of firearms, including handguns, rifles, and shotguns.

  • Shotshell: Shotshells are cartridges designed for use in shotguns and contain multiple pellets (shot) for hunting birds, small game, or clay target shooting.

Reference

  • "Forensic DNA Typing" by John M. Butler

  • "The Forensic Casebook: The Science of Crime Scene Investigation" by Ngaire E. Genge

  • "Forensic Science: A Very Short Introduction" by Jim Fraser

  • "Practical Crime Scene Processing and Investigation" by Ross M. Gardner