Ballistics 101: Understanding Bullet Trajectories and Terminal Ballistics

Ballistics, the science of projectiles and firearms, plays a crucial role in understanding how bullets behave from the moment they leave the firearm to the point of impact. This field is divided into several categories, with two of the most significant being external ballistics (bullet trajectory) and terminal ballistics (the effect of the bullet upon impact). This introductory guide aims to shed light on the basics of bullet trajectories and terminal ballistics, providing a foundational understanding for enthusiasts, hunters, and tactical professionals alike.

External Ballistics: The Journey of the Bullet

  • What is External Ballistics? External ballistics deals with the behavior of the bullet in flight. It encompasses the path the bullet takes from the barrel of the gun to the target.

  • Factors Influencing Bullet Trajectory: Several factors affect a bullet's trajectory. These include:

    • Gravity: Once a bullet leaves the barrel, gravity acts on it, pulling it downwards.

    • Velocity: The speed of the bullet as it exits the barrel influences how far it can travel and how quickly it will drop.

    • Air Resistance: Bullets are slowed down by air resistance, which increases with distance.

    • Wind: Wind can push the bullet off course, affecting accuracy, especially at longer distances.

  • The Bullet's Path: Understanding the bullet's arc, which is not a straight line but a curve, is crucial. The bullet rises slightly after leaving the barrel (if the barrel is slightly angled up) and then begins to drop due to gravity.

Terminal Ballistics: The Impact of the Bullet

  • What is Terminal Ballistics? Terminal ballistics is the study of the bullet’s behavior and effects after hitting the target.

  • Factors Affecting Terminal Ballistics:

    • Bullet Design: The construction and shape of the bullet determine how it behaves upon impact. Hollow-point bullets, for example, are designed to expand upon entering a target, causing more damage.

    • Impact Velocity: The speed of the bullet at the time of impact affects its penetration and expansion.

    • Target Material: The composition of the target (e.g., flesh, bone, ballistic gelatin) influences how the bullet transfers its energy and causes damage.

Practical Applications of Ballistic Knowledge:

  • For Hunters and Sport Shooters: Understanding ballistics is crucial for accurate shooting, particularly at long distances. It helps in making the necessary adjustments to aim and in selecting the appropriate ammunition for the intended purpose.

  • For Law Enforcement and Military: Knowledge of terminal ballistics is vital for selecting ammunition that will effectively neutralize threats while minimizing collateral damage.


A fundamental understanding of ballistics is essential for anyone involved in shooting disciplines. Grasping the principles of bullet trajectories helps in accurate shot placement, while an understanding of terminal ballistics is crucial for comprehending the effects of a bullet upon impact. Whether for hunting, sport, or tactical use, a solid foundation in ballistics enhances both the effectiveness and safety of firearm use.

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