Shooting Holes in Wounding Theories: The Mechanics of Terminal Ballistics

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. I try not to speak dogmatically on subjects beyond my ken, but where the concensus of thought by sage and seasoned 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 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 terminal effectiveness.

Why not have your cake and eat it too? Try the Beowulf 50 cal AE upper receiver for the AR 15. 50AE round, semi-auto, 7 rounds in a modified M16 magazine. Here's a link:

http://www.gunbroker.com/auction/ViewItem.asp?Item=19581021

BTW, I was being a little sarcastic, since the topic was wound size vs terminal velocity. You can have both in the 458. (and the 50AE, too!) You are right about the single shot. It is normally encountered in a four shot bolt action.

As far as home defense goes, it depends on how much shooting you expect the engagement to require. A .22 might require more than just a few shots to get a youthful thug, scared and full of adrenaline (or drugs) to go down and stay down.

Remember that recent home video footage taken outside a courthouse where a disgruntled client made a "final payment" to his least favorite lawyer using a small caliber hand gun (.22, .25, .32)? He emptied the gun into the man (can't recall if it was a revolver or a semiautomatic) from about two feet away. The shooter was firing from waist level, so it is hard know how many hits were actually scored. The one thing that didn't happen is that the victim didn't go down. He backpedaled away, held his hands in front of his body, cried for help, tried to hide behind a tree, etc. The shooter, frustrated, finally fled and was run down by a sheriff/bailiff; his girth being too ponderous to permit a true getaway effort.

Returning to the young, scared criminal in the dark, are you prepared to reload in the dark to make sure that he (or them) goes down? If you live in a isolated location where 15-20 shots fired in the dead of night would go unreported, you have some decisions to make, like 1) how to explain it to the police when ballistics analysis shows that the last six when into the dead guy AFTER he was on the ground, or 2) whether or not report it at all (and take care of the cleanup yourself). No. 2 is not such a good idea because there can always be a lookout or driver waiting outside. And he/she is going to go home and start talking about it and the next thing you know you're doing No.1 anyway. If you live in more populated areas, the police are probably going to be there pretty quick even if you didn't call them when the break-in/disturbance began.

So, if you have crossed the mental Rubicon and decided that you will shoot to protect yourself or your family members, you might as well choose a weapon whose first shot (and every shot thereafter) has the capacity to fatally wound/kill outright. It's just easier to 'splain it to the police if there was only one shot fired (in fear of your life before the police got there, of course) and the dead guy took it standing up (preferably delivered to the front of the upper body). Keep the story simple.

Since sight alignment and trigger squeeze can be just a little off when YOU are full of adrenaline and in the dark, the weapon of choice is a short barrel shotgun.
Personally, mine is a pump action deerslayer style 12 gauge with a magazine extender tube. I keep it loaded with a mix of 00 buckshot and 1" slugs (wound, kill, wound, kill, etc..). I have practiced getting it out and moving through my home with it in the dark (dry fire, of course). I have never had to get it out for real and hope I never will.

I'm with you 100&% on the .308

However right now my 'main line' rifle is a Yugo M48, 8mm Mauser (Which is really a licensed German 98k Mauser).

The ballistics are fairly close to the .308 (maybe a tad slower) and if my math is right the 8mm (7.92) works out to .31 caliber. But in any case, a .30 caliber is mandatory as far as I'm concerned for 'serious' shooting.

I almost feel sorry for those who spend all that dough on an AR-15 and clones with that wimpy .223 Remington. Heck I'd take an AK or SKS with the 7.62x39 over that any day.

I also have a 9mm Carbine - or as DiFi would say, an Assault Rifle. I bought that for, ahem, 'close in work'. It's good to 100-125 yards. And being 9mm it's the same as my 'main' sidearm so ammo is no problem.

And for my nightstand I have a 9mm Makarov (9x18) loaded with Hi-Vel 95gr JHP Cor-Bon's. This gun was once property of the East German Ministerium für Staatssicherheit (Stasi).

Anyway, I'm pretty well set - for now. But there are about four guns still on my 'wish list'. Isn't there always :-)

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