Shooting Holes in Wounding Theories:

I. Introduction

II. The Mechanics of Terminal Ballistics

a. Mechanics of Lethal Wounding

b. Mechanics of Terminal Ballistics

c. Mechanics of Penetration

d. Mechanics of Cavitation

III. Myths, Misconceptions and Miscalculations

a. "Energy Dump", "Overpenetration" and "Hydrostatic Shock"

b. Momentum and "Stopping Power"

c. Thresholds of Wounding Potential Based on Kinetic Energy

d. Optimal Game Weight (OGW) Formula

e. Taylor Knockout (TKO) Formula

f. Lethality Index Formula

g. Knock-Out Value (KOV) Formula

h. "When Good Physics Goes Bad"

1. Relationships of Force, Momentum and Energy

2. Bogus Ballistics

IV. Empirical Methods of Estimating Actual Terminal Effect

a. Performance of Non-Deforming Bullets

1. Flat-Nosed Handgun and Rifle Bullets

2. Round-Nosed Solid Rifle Bullets

b. Performance of Deforming Bullets

1. The Handloader-Sciuchetti Study

i. Observations from the Sciuchetti Data - The Effect of Impact Velocity

ii. Controlled Expansion versus Controlled Retained Weight

iii. Further Observations - Discontinuities Near the Hydrodynamic Threshold Velocity

2. Minimum Wound Dimensions

3. Medium-Bore Bullets

i. .308 Caliber

ii. .338 Caliber

iii. A Study of Sectional Density

iv. .348 Caliber

v. .375 Caliber

4. Small-Bore Bullets

i. Premium Bullets in .284 Caliber

ii. Another Study of Sectional Density: Small-Bore

iii. Too Light for Big Game? .224 and .243 Calibers

5. Handgun Bullets

6. Large-Bore Bullets

V. Analytical Modeling of Terminal Ballistics

a. Introduction

b. Fidelity in Modeling

c. A Simple Analytical Model of Bullet Penetration

No subject in the firearms industry generates more print or heat than terminal performance. In the last fifteen years this issue has even become one of considerable moment with federal agencies, the FBI particularly, leading to the decision to replace entire arsenals of sidearms. Similarly, within the commercial industry we have seen the development of numerous, and occasionally exotic, bullet designs based upon various theories of wounding behavior. Some have worked well, while others have not. But for the most part, shooters and many in the firearms community still do not understand why these things work or fail. My purpose in this study is to examine what we do know and to reconsider the theories which attempt to account for the observed performance. I intend to cover the entire field of terminal ballistics controversy as fairly as possible, but I do have some very definite conclusions of my own which I believe I can explain and defend to the satisfaction of most. Furthermore, I will offer some criticism of the popular formulas for calculating terminal performance and suggest a couple which may provide a real estimate of absolute performance on game (not just a relative comparison to other loads). Although this discussion is intended for the sportsman, I will include material and argument which is of interest to the individual using small arms for self-defense or in police or military applications.

A brief word about my background is warranted. I am a mechanical engineer by profession and employed in the defense industry as an analyst and designer of anti-armor lethal mechanisms (ie, warheads and penetrators). Terminal ballistics is both my hobby and my profession. On the job I use a computational tool known as a "hydrocode" called CTH, which was developed by Sandia National Laboratory, to perform penetration analyses, along with code that I have written for specific applications. My knowledge and studies cover the entire spectrum of penetration mechanics from small arms to high explosive shaped charges. I have extensively read the best forensic studies of bullet behavior, as well as the classic works on field performance by Whelen, Baker, Selous, Taylor, O'Connor, etc. While I freely admit that I haven't personally shot a great number of game animals, I have witnessed others being shot and examined still more post-mortem, to confirm or refute by my own experience the published observations and pontifications of hunters and firearms pundits. I try not to speak dogmatically on subjects beyond my ken, but where the concensus of thought by sage and seasoned scientists and hunters tends toward a clear conclusion, I am not hesitant to assert it.

I believe in being forthright, so I will jump in with both feet and state the premise of my own theory of terminal ballistics. The title of this article is a hint. Plainly stated, I maintain that the effect of bullets upon living targets is caused by the wound track made by the bullet. Now, before you accuse me of being a wise guy, recall that most theoretical explanations of wounding that are batted about in the shooting community are tied to the kinetic energy or momentum or some other such physical quantity of the bullet which is "transferred" or imparted to the target. My theory recognizes these characteristics, but relies upon a fundamentally different premise, which is that two physically equivalent wound tracks in a game animal will have an equivalent effect, no matter how different were the kinetic energies or other physical attributes of the bullets which caused them. There are some extremely rarely encountered exceptions to the general rule, but for most purposes the hole caused by a bullet is its only measure of lethality.

II. The Mechanics of Terminal Ballistics

These pages are intended for a serious examination of the subject of terminal ballistics as it applies to the hunter (principally). Necessarily, some of the details of the discussion involve matters which some minds may regard as gruesome, possibly even disturbing. While there are no graphic depictions of wounds on this site and its associated pages, the effects of bullets are discussed in graphic (albeit scientific) terms. Anyone who finds the whole subject of hunting and guns to be unsettling may well want to depart without perusing the contents of this site. I accept no responsibility whatsoever for any psychological traumas, mishaps, misfortunes, or bad karma alleged to result from viewing this site, whether real, imaginary or pretended. On the other hand... if one's mind is not frozen in prejudice (or alternatively, absorbed by perverse morbidity), then I would invite newcomers to the world of sport hunting to examine these pages and discover the non-sensationalized real face of modern hunting. I hold very high ethical standards and one will find that ethics is a recurring theme on this site.

In regard to legal issues, all of the references used on this site are annotated where known (or if not, please bring them to my attention). This is not a commercial site, nor does the author receive any remuneration from any manufacturer. The purpose of this site is purely educational and the views expressed (except where noted) are those of the author. I will not accept any responsibility for mishaps alleged to result from the use of information contained on this site. All of the information here is true and accurate to the best of my knowledge (which is limited). Beyond that, you're on your own.

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