AFRICA HUNTER QUEST© 

Chapter 7 - THE CONCEPTUAL WOUND CAVITY 

GG:   Have you at least ordered Robertson’s book? 

D:      No. 

GG:   It’s a must read before you go to Africa. 

    Robertson could have had a day job as a licensed veterinarian. Instead, he chose to make a living as a licensed PH in Africa. He has decades of experience cataloguing how various animals react when shot with different chamberings and bullets. He probably has done thousands of autopsies on these same animals, looking for anatomical clues of why an animal reacted either favorably or unfavorably in response to impacts from the chambering-bullet combo. I consider him authoritative on this subject. Not only that, he has no apparent blatant vested interest in rifles, ammunition, actual bullets or using the media as a primary source of income. I truly believe what he has written is in the best interest of anyone wanting to hunt in Africa. Some of what you and I will discuss about a wound cavity has its basis in what Robertson has to say.  

     Robertson repeatedly talks about a “wound channel” into and through the heart-lungs as being primarily important for producing a quick death. Quite simply, a bigger wound channel is better.  

     Because I am part civil engineer, I always have had trouble with his choice of the word ‘channel’ in the context of how he uses it. I think of a channel in terms of a stream bed: the channel has a bottom and two sides; no top. A cavity typically has some form of a circular section and is normally enclosed except for the entrance and any exit hole. Therefore, I have chosen to call the tissue disruption caused by a bullet a cavity rather than a channel.  

     D:      So, you are already arguing with someone you have called an expert. That doesn’t inspire much confidence in what you have to say on this subject. 

     GG:   I am not arguing with the man’s concept, just modifying his terms. To me, concepts are the most important. The terminology can be confusing in trying to understand the concept. Sorting through the terminology to get at the essence of the

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concept is the toughest part of truly learning something instead of parroting buzz words. 

     For example, just what is the wound cavity? Doctor Martin Fackler was a military physician and did extensive studies concerning the effects of wounding by small-arms fire on combatants. I interpret what he called the “permanent wound cavity” is the actual hole made through the tissue by the bullet and the blood-shot tissue that surrounds it. 

     I say interpret because Dr. Fackler, as far as I know, never uses the term ‘blood-shot’ in his descriptions or pictorial sketches of wound cavities that I have seen. Once again, lack of common denominator terms, their definitions, and their conceptual understanding prevented me from positively understanding what an expert like Dr. Fackler was trying to say. Dr. Fackler believed that the shape and extent of this permanent wound cavity caused by a bullet is related to its “stopping power”. The larger the wound cavity volume, the greater the stopping power of the bullet.  

     Both Robertson and Dr. Fackler are likely saying the same thing, but the terminology is way different. As exemplified with the stitching needle example, I conclude that as the wound cavity volume gets progressively larger, the prospect of death progressively increases and the time to death gets progressively shorter. In qualitative terms of time, this wound cavity volume progression transitions the time frame from ‘debilitate’ to ‘kill’ to ‘stop’. 

     Dr. Fackler arrived at his conclusions through extensive bullet testing into ordinance gel. He noted that there was a temporary expansion cavity formed as the bullet passed through. If you watch a slow-motion video of a gel test, you can see the bullet impact produces pronounced bulging of the gel block well beyond its pre-impact dimensions. After bullet passage, the block exterior reverts back to its original shape and dimensions. 

     The full extent of the gross bulging expansion in the block beyond its initial exterior dimensions is obviously temporary. Dr. Fackler apparently believed this temporary expansion was of no real value in assessing a bullet’s lethality or stopping power. 

     After the bullet passes through the block and it reverts back to its original shape, you can see a relic cavity shape cast within the block’s interior. This shape has been formed by internal fractures in the gel that radiate outward at a 90-degree

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angle from the trajectory of the bullet as it passed through the gel. This shape is visible in all types of gel, but is obviously apparent in clear synthetic gel like I used for my testing. Based on my testing, I believe qualitative interpretation of the general cavity shape is a key to understanding the terminal performance tendencies of bullets based on their generic design. I further believe that calculating the actual volume of the cavity is a way to quantitatively judge and even rank the terminal performance of bullets, regardless of caliber.  

     Because I could not be absolutely sure if Dr. Fackler included what a hunter would call blood-shot meat in his definition of a permanent wound cavity, I came up with my own wound cavity model to evaluate what happens to tissue in response to passage of a bullet based on Dr. Fackler’s sketches, skinning shed autopsies, and gel blocks cavities I observed when I did my own gel testing.  

     Quite simply, I am including the bullet hole and all blood-shot tissue in what I am calling a wound cavity. The radial extent of the fractures in the gel caused by the bullet’s passage models and defines the radial extent of blood-shot tissue. My wound cavity model may actually be identical to Dr. Fackler’s.   

     There is an apparent divergence of my presumed conceptual model with Dr. Fackler’s. Based on summary accounts by others, Dr. Fackler believed that “pressure waves” produced by passage of a bullet through the tissue played little to no role in producing incapacitation. He cited the effects of sonic waves on the body as evidence. However, sonic waves are not fluid compression waves, the wave created in the blood by passage of a bullet. As I have already described, I believe such compression waves can induce pressure in the blood significant enough to burst its containment vessels: the capillaries in the cells. Although the pressure is dissipated somewhat by the elastic nature of the tissue, some degree of blood pressure increase can logically be assumed to be transmitted throughout the body. I believe magnitude of this pressure increase can apparently be great enough to cause damaged cells to switch off the central nervous system. An animal dropping to the shot when the aim point is the lungs is at least anecdotal testimony to this speculation. I believe specific measurements of the cavity housed within the gel can provide an indicator of a bullet’s potential to cause this effect.  

     Someone way smarter than me with expert credentials in anatomy/physiology would have to pass final judgement on my speculations. Regardless, my model made sense to me as a hunting layman with an engineering background and ultimately served my purpose of evaluating the terminal performance of various hunting bullets. 

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     D:      So, now you are either arguing with or ignoring the research of an actual physician, an acknowledged expert in the field of ballistic terminal performance! 

     GG:   Are you totally unwilling to consider my methodology based on technical merit? Are you calling me a denier or the current, more trendy “purveyor of hate speech”? 

     Donny sat in silence. “Damn him.” 

    GG:   There are huge differences in terminal performance considerations and actual bullets used in a combat situation versus a typical Africa standard practice hunting situation. In a combat environment, the ball ammo bullets used are not purposely designed to expand. As such, there really isn’t a comparatively large volume of blood-shot tissue created in relation to the actual volume of the bullet hole. Thus, I believe there is limited, modest potential for inducing hydrodynamic shock.  

     In a combat environment there is typically no specific aim point, only a generalized ‘center mass’. Most shots tend to be full frontal that may or may not take out a vital organ. Because the shot is center mass, the mobility of the legs is not directly affected. Lots of little holes, as in .224-caliber, or one big hole, as in 50-calber, all preferably clean through, are necessary to stop an assailant. Operative word: stop. Operative concept: an actual hole or holes clean through. The potential benefits associated with any blood-shot tissue are marginal to negligible. 

     Shooting non-dangerous game in a typical Africa hunting scenario is very different. The bullet is way different because it is specifically designed to expand. This expansion produces both a larger hole and a larger volume of blood-shot tissue than that produced by a bullet typically used for combat. Because there is a greater volume of blood-shot tissue, I believe there is a greater potential for inducing hydrodynamic shock. The wound cavity, regardless of shape, is comparatively ‘large’ because of the bullet’s expansion. 

     The shot angle and aim point are also way different. The desired hunting shot angle is full broadside. As opposed to combat, there is typically time available for that preferred orientation to present itself. That orientation allows selection of the preferred aim point: the shoulder. That general aim point also allows debilitation of the animal’s mobility because an actual hole and an extensive volume of blood-shot muscle mass affect the functionality of a leg. Moreover, a full broadside shot angle

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on the shoulder allows a far more refined and strategic aim point: the heart. Getting to the heart or the major plumbing above the heart also means that both lungs will likely be perforated. 

     Because the bullet must fully penetrate shoulder muscles to get into and through the boiler room, I believe the benefit of blood-shot tissue is no longer marginal to insignificant. Quite simply, I believe more blood-shot tissue is better for two reasons. First, I believe the volume of blood-shot tissue produced by a bullet is directly related to its ability to produce hydrodynamic shock. A bullet that creates a greater volume of blood-shot tissue likely broadens the range of blood pressure within the animal beyond simply a peak pressure where hydrodynamic shock could potentially occur. Second, and far more important, the volume of blood-shot tissue is directly related to the incapacitation inflicted on the animal both in life-vital organs and in its ability to flee to safety.  

     In my opinion, the larger the wound cavity volume that includes blood-shot tissue, the greater the likelihood of a recovered animal. I think you can now appreciate why I had concerns about how Dr. Fackler modeled blood-shot tissue, and why I have specifically included it in my wound cavity model. 

     D:      But the meat damage would be awful. 

     GG:   Trophy hunting in Africa is all about recovering an animal, meat damage be damned.  

    For all these reasons, what I am calling the wound cavity includes the blood-shot tissue surrounding the actual bullet hole.  My gel testing showed that the bullet’s generic design affects the general shape and volume of this cavity. The cavity’s shape, volume, and length helped me make what I think are reasonable decisions regarding the hunting bullets I have chosen to use. 

     I believe there are three general shapes of wound cavities produced by expanding hunting bullets: the pissed-off blowfish, the finless guppy, and the eel-snake. The variability of these shapes conceptually represents the variability and extent of the blood-shot tissue in the wound cavity model.  

     A wound cavity that looks like a pissed-off blowfish is created by a bullet with a primary design emphasis focused on expansion at the expense of penetration. The wound cavity is primarily ball-shaped and would be created by a bullet acting like a grenade. Bullet fragmentation is significant to catastrophic. The ball shape

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represents the extreme lateral extent and limited longitudinal, or penetration extent of blood-shot tissue cause by the limited travel distance of the bullet. There is no appreciable tail on a blow fish. If you consider the mouth of the blow fish is where the bullet entered, this lack of a tail reinforces the concept of lack of penetration.  

     A wound cavity that looks like a finless guppy is created by a bullet with a design emphasis of balance between expansion and penetration. These bullets expand less and at a slower rate than do the pure expansion bullets. They also tend to fragment less. If you consider the mouth of the guppy is where the bullet enters, there is a pronounced upward body taper through the head into the somewhat bulbous thoracic cavity where it then tapers back down toward the tail. The head and thoracic cavity of the guppy contain the conceptual majority of the blood shot tissue. Beyond the thoracic cavity, the volume of blood-shot tissue steadily decreases with increasing distance into the tail. The combined length of the head and bulbous thoracic cavity is comparatively the same as the tail length of the guppy, conceptualizing this balance between wound cavity production and penetration. 

     A shape that looks like an eel-snake indicates a bullet with terminal performance heavily skewed toward penetration. These bullets typically expand less than those with a balanced design and also at a slower rate. Most of these designs result in a bullet that exhibits little to no fragmentation. 

     The reason I say eel-snake in describing the shape is there really is no one critter that approximates it. If you find a picture of a black edge moray eel, it comes the closest. If you again consider the mouth as the entrance point of the bullet, there is a gradual upward body taper to the head where it kindly becomes a constant diameter. With most any eel, there is little to no downward taper of the body toward the tail, and this lack of appreciable taper is uncharacteristic of what the cavity formed by a penetrator bullet looks like. To visualize the cavity shape of a penetrator bullet in the gel block, you would have to look at about the 50% length point on the eel and visualize a significant downward taper to about its 67% length. At that juncture the shape pretty much reduces to one of a garden snake and continues in that shape to the bullet’s termination point.  

     The thoracic cavity diameter of an eel is small compared to its head and represents the reduced volume of blood-shot tissue created by these penetrator bullets. The length of the tail of this fictitious critter is comparatively long compared to its combined head-and-thoracic-cavity length, and thus symbolizes the emphasis on penetration. 

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     As GG was explaining his conceptual wound cavity model shapes, he saw the Pilgrim reach for his phone and begin to frantically punch and swipe its face. GG was both amused and mildly irritated. The youngun was so flustered and distracted he had forgotten there was no phone signal at this particular range. If the little twit hadn’t gone fishin’ with his phone, GG would have sketched out the shapes and explained the differences. GG knew there was an incoming, and was prepared.    

     D:      This is so bogus!! Is there anybody you don’t argue with?! Is there nothing too ridiculous to make up?! I suppose you are now gonna tell me my ammo controls all these presumed shapes! 

     GG let him have it with the other barrel. 

     GG:   Yep.  

     Donny audibly groaned.  

     D:      Ammo affects all this, even with a premium bullet? 

     GG:   Yep. Not only does the bullet’s generic design affect the cavity shape, the impact velocity affects it as well. Depending on the impact velocity, you could have a bullet that would normally produce a blowfish shape actually produce a shape that looks more like a guppy.  

     Donny groaned again. 

     D:      (Shaking his head) Blowfish turning into a guppy . . .  I was under the impression that I had a premium bullet. Are you telling me I don’t have a premium bullet? 

     GG:   Yep. It wouldn’t matter anyway. A premium bullet has nothing to do with it.  

     D:      Then just what is a premium bullet? 

     GG:   My definition? 

     D:      Any definition is better than no definition, even yours. 

     GG:   (Grinning to the point of almost laughing) Ouch!  

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    Any bullet that can satisfactorily withstand an impact velocity greater than 2700 fps on the shoulder. 

     D:      (Wincing) That doesn’t help me at all. How can I identify an actual bullet on the shelf that likely can withstand an impact velocity on the shoulder greater than 2700 fps? 

    GG:   You didn’t fully evaluate my definition. I said satisfactorily withstand an impact velocity of 2700 fps. You didn’t ask me the most important question that you could have.  

    Donny was beginning to get really pissed and his head hurt. Damn the Geezer; he was making this way harder than it needed to be. Too many questions, too many facts and concepts. Not enough answers. 

     D:      All right, I’ll bite. What question should I have asked? 

     GG:   What do you mean by satisfactorily?  

     Donny again audibly groaned. “Here we go again,” he thought.  

     D:      All right. What do you mean by satisfactorily? 

    GG:   Excellent question! We have finally gotten to the heart of the matter. Only you can define ‘satisfactorily’. In doing so, you have defined not only your hunting problem, but the terminal performance you believe is needed from your bullet in order to successfully take your animal.  

    Donny finally had enough. It never ended with the Old Man. False clarity cloaked in what Donny suspected were speculative, unproven concepts. Worse still, the concepts were never linked to reveal a clear path to a decision about his 270 Winchester and could be considered nothing more than esoteric factoids. Although the old coot had been to Africa, that didn’t make him an authority or expert. It didn’t take a rocket scientist to figure out that geotechnical engineering and animal physiology were not even remotely related. GG had given the impression that most everybody was wrong but him. He was likely just a reincarnated Don Quixote crazy man. 

     GG could read the youngun like a book.  

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    GG:   We choose what we choose based on how we define the problem and the risks we’re willing to assume to get the outcome we want. Mitigating or accepting risk means hard decisions must be made concerning the advice we have been given.  

    Pilgrim, good advice is where you find it. You first need to decide if you have found it. If you decide you have, then you need to figure out if you actually want to apply it and how. Your choices, your decisions. 

    What I think about what you want to do and how you actually want to do it pays me too much homage. All I know is that you potentially have at least a $2,500 trophy fee at risk for an unrecovered kudu. It would be unconscionable of me not to give you the benefit of what I have learned to reduce the probability of that actually happening. 

    “Nuts,” thought Donny. A lost animal and the privilege of paying for it were now in sharp focus. 

     D:      (Stiffly) Thank you for your time, sir. I appreciate your concern. 

    GG watched the Pilgrim get up and leave. He suspected the youngun would be back, sooner rather than later. 

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