Terminal Ballistics – Part I

Understanding bullet impacts.

Terminal Ballistics - Aegis Academy - Part 1 - Howard HallTerminal Ballistics – Part I is the first in a two-part series which will begin to conclude the Ballistics Series by introducing the principles within Terminal Ballistics and focus on the various aspects of projectile impacts on target and their immediate effects.  Leveraging the key concepts of projectile flight and construction, momentum and kinetic energy introduced earlier in the ballistics series, this article will illuminate some scientific facts in regard to the terminal effect of firearm employment for hunting, law enforcement and personal defense while also debunking some commonly-held myths.  In researching this topic, I’ve relied heavily on authoritative sources such as Robert Rinker’s “Understanding Firearm Ballistics, 6th edition,” and the Federal Bureau of Investigation’s 1989 report titled “Handgun Wounding Factors and Effectiveness.


Whether for recreation, competition, training, hunting or personal defense, this ballistic series has focused on the myriad of aspects … Read more »

Handgun Ammunition Velocity

The impact of barrel length on Velocity



This article will both answer a reader question regarding handgun ammunition velocity and serve as a perfect segway into the upcoming Terminal Ballistics series.

“I’ve thoroughly enjoyed the Internal and External Ballistics series.  It seems, however, that most of your material applies to rifles and rifle ammunition.  I’ve recently read about Remington’s Ultimate Defense ammunition designed specifically for compact handguns.  You’ve mentioned barrel length in your Internal Ballistics series contributing to precision and accuracy, but haven’t spoken very much on velocity.  How much does barrel length impact ammunition velocity in compact pistols?” – Mark in Murrieta

Thank you for the note, Mark.  I appreciate the question and the opportunity to answer it here.  As a general principle, barrel length and initial velocity are directly proportional… meaning that longer barrels tend to produce higher muzzle velocities and shorter barrels tend to produce lower … Read more »

External Ballistics Part IV – Deviation, Gyroscopic Drift and Wind Deflection.

10644411_10203155525863801_2881496486091301946_nExternal Ballistics Part IV – Deviation, Gyroscopic Drift and Wind Deflection

Thank you for your continued interest in ballistics: the science of shooting!  We have covered a lot of ground throughout this series in order to build to this last set of concepts and principles that will help you accurately and consistently place your shots on target.  We will finish our discussion on External Ballistics by discussing Deviation, Gyroscopic Drift and Wind Deflection.


The dictionary defines deviation as the difference between an expected and observed outcome or as the difference between the average outcome and a particular outcome.  For our purposes, the “outcomes” are projectile impacts on target and a deviation is the difference between the point of aim and the point of impact or the difference between one particular impact and the rest of the group.

accuracy precisionI first introduced the difference between mechanical precision and shooter accuracy … Read more »

External Ballistics Part II – Flight to Target

External Ballistics Part II – Flight to Target

Thank you for returning to continue our study of ballistics.  In this article, I will pick-up where we left off from our previous discussion of External Ballistics and focus solely on the projectile’s flight to target.  Before introducing the key concepts of kinetic energy, gyroscopic stability and ballistic coefficient, I will provide a brief review to fully set the stage.

During our discussions on Internal Ballistics, we focused on firearm function, reliability, safety and mechanical precision. The complex sequence of interactions that initiate a projectile’s movement from the cartridge case to the end of the barrel.  Essentially, it helped us understand how “our” interaction with the firearm affects its function and the start of the projectile’s travel to target.

During our first discussion on External Ballistics, we focused on the principles of Newtonian Physics and the short period of projectile instability caused … Read more »

Internal Ballistics Part III – Ammunition Characteristics and Safety

ammunition characteristics, aegis academy, howard hall, firearms training, firearms instructor, internal ballistics, pistol shootingInternal Ballistics Part III – Ammunition Characteristics and Safety

Thank you for your continued interest in the study of ballistics.  So far, we’ve covered the broad framework of firearm ballistics followed by two in-depth discussions regarding internal ballistics (firearm function and mechanical precision).  In this article, I will conclude our discussion on internal ballistics by focusing on ammunition characteristics and safety.

In contrast to firearm function, which focused on the mechanical interaction of individual firearm components, understanding ammunition requires a focus on the thermodynamic conversion of chemical potential energy into kinetic energy.  At the center of this energy conversion is the important concept of pressure.  Rapidly expanding gasses create the pressure required to expand the cartridge case against the inside of the chamber, propel the projectile forward, and cycle semi-automatic weapons.

ammunition characteristics, aegis academy, howard hall, firearms training, firearms instructor, internal ballistics, pistol shootingAttaining consistent and safe pressure is the key to precision and reliable firearm function.  Too little pressure … Read more »