Book Chapter 19-Home

Hunting Bullet Metrics

Apply Terminal Performance Truth

AFRICA HUNTER QUEST©

Chapter 19 - THE GEEZER’S VALIDATION OF HIS EMPIRICISM

As he drove home, Donny tried to process and catalogue the concept and data dump GG had just provided. He was not very successful. “Concept chaos,” thought Donny. “Too many concepts with too many abstract applications. Too much data and test results I really can’t relate to. Too many potential ‘what- ifs’ and ‘if-thens’. Nothing definitive to focus on to begin to lock anything down with my 270 Winchester.” Or was there?

“What about my 130-grain bullet?” he thought. “Why does it give reasonable to good performance at the farm? Is it really because the animal, impact velocity, and the bullet’s generic design are all interrelated.?”

When he got home, Donny sat down at his computer and brought up the ballistic software program he had been using. He plugged in his muzzle velocity and the published BC for his bullet. He specified output that included impact velocity in fps at 10-yard increments out to 450 yards. The output displayed on his screen showed impact velocities ranging from about 2500 fps at 340 yards, his minimum range, to about 2300 fps at 450 yards, his maximum.

“Dang.” thought Donny. “Impact velocities bracketing a 2400 fps cup and core sweet-spot.” Shots that had hit the lungs generally passed through, giving a good blood trail. He couldn’t recall having to track a deer more than about 200 yards, with the longer tracks oddly corresponding to the lower impact velocity of 2300 fps. Less bullet expansion?

If the shot drifted into the shoulder, the bullet typically stayed in the animal. Although he had never had an animal drop to any shot, the ones shot in the shoulder had never traveled more than 100 yards, typically less. When shot on the shoulder, the volume of bloodshot meat was noticeably larger, potentially indicating a greater wound cavity volume. What GG had told him about the cup and core bullet performance seemed to generally correspond with what he had observed. Bullets passing through presumably denser, thicker tissue likely expanded more but penetrated less.

Donny decided that a strategic calculation of estimated game weight using GG’s empiricism could now potentially make sense because he had a specific hunting

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scenario to model. The deer he shot typically weighed less than 150 pounds. Punching numbers into to GG’s empiricism, he determined the 130-grainer with an impact velocity of 2300 fps indicated an estimated animal weight on the order of 300 pounds, certainly adequate for his white tail hunting scenario.

What about shots in Africa? Although he didn’t know what his shot distances would likely be, he suspected a 340-yard shot was not common based on most of the videos he had seen. GG had said his typical shots in the Limpopo ranged from about 90 to 200 yards, with an average of about 135 yards. What was the impact velocity of his bullet at that average distance?

Donny once again strategically eyed his computer screen, fixating on the impact velocity shown at 140 yards. 2900 fps! “Geeze Louise,” thought Donny, “the same impact velocity that GG had speculated for the disastrous blue wildebeest hunt with a 300 RSAUM!”

The jumbled conceptual puzzle pieces were now fitting together to tell quite the story. With an impact velocity of 2900 fps, his 130-grainer might not even get into to a kudu’s boiler room with a shoulder shot at 140 yards. No wonder GG had tried to point him in another direction.

What about the estimated game weight for a 130-grainer at 140 yards? A few quick keystrokes on his calculator yielded about 370 pounds, way shy of a prime kudu bull. Even if GG’s empiricism was bogus, a 130-grain cup and core on the shoulder of a kudu at 140 yards potentially wasn’t even close to stout enough for a no-drama outcome. At the very least, a bullet with a different generic design was now in play if he selected a 130-grain weight.

Donny continued to roll with his ‘what if’ scenarios. What if GG’s empiricism was reasonably accurate? What estimated game weight would a 150-grain bullet be capable of at a Limpopo average shot distance of 140 yards? What would be its impact velocity?

He went online and found ammo loaded with a 150-grain, poly-tipped cup and core bullet. The manufacturer had a stated muzzle velocity of 2860 fps. The bullet had a published BC of .525. When he plugged these new parameters into the ballistic program, the bullet’s estimated impact velocity was a little over 2600 fps. “Impact velocity less than 2700 fps,” thought Donny. “Good for a broadside shoulder shot.” He eyed the screen for the kick-out impact velocity of 2700 fps. “Ninety yards,” he thought; “the minimum shot distance GG said he had taken in the Limpopo.”

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Donny continued to eye the velocity printout on his screen. He remembered that the shot distance on the kudu in the video he had seen was 40 yards. The corresponding velocity displayed was about 2800 fps. “Potentially getting dicey for a shoulder shot,” thought Donny.

What was the estimated game weight at both 40 and 140 yards? The few quick keystrokes on his calculator yielded an estimated game weight of only about 475 pounds at 40 yards, and about 435 pounds at 140 yards.

Donny stared at his calculator. “Over 100 pounds less than a magnum kudu bull, even at only 40 yards with an out-of-bounds impact velocity,” he thought. He felt like a touchdown pass had just been called back due to a holding penalty. The Old Man had gotten into his head. “Number crunchin’ is one thing,” thought Donny, “but what does a real expert have to say about it?”

Donny went back and reread Robertson’s thoughts about rifle, caliber, and bullet selection for a kudu. As he reread, he realized he was using both the impact velocity and the estimated game weight filters GG had shown him. He now had a numerical representation for possibly interpreting why Robertson hadn’t mentioned the 270 Winchester in short-range/thick brush situations: concerns about short-range bullet performance due to potentially high impact velocity, coupled with too light a bullet weight to take a kudu at any range. His revelation with GG about impact velocity issues with a 150-grainer had been dead on. The only reason a 270 Winchester with a 150-grain cup and core bullet could be back on the table for a long-range shot was the impact velocity had been suitably reduced for likely satisfactory terminal performance.

That being said, he sensed Robertson was giving the same PC response he had gotten from the PHs in Harrisburg. The 270 Winchester and a 150-grain bullet combination was just plain lower bound for a kudu, with bullet weight and related impact velocity being the concern given the hunting scenarios he had just modeled.

Donny focused on part of one sentence in Robertson’s book: “I believe that the 7-millimeter magnum with either 160-grain or 170-grain bullets would be a better choice for such long shots . . .” If Robertson had simply deleted the reference to a 7-millimeter magnum chambering, the man was recommending bullet weights of 160 to 170 grains.

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Donny recalled one of the PHs in Harrisburg saying that his recommended chambering for a kudu was a 7-mag with a 175-grain bullet. Damned if there wasn’t an apparent harmonic convergence. Everybody appeared to be on the same page, not the least of which was the Geezer with his funky empiricism.

Donny sat there stewin’ and chewin’. There were two things that bothered him. First, Robertson hadn’t considered the 270 Winchester with any 150-grain bullet for close-in shots in the bush, but indicated that long-range shots with one could work. That seemed at odds with the approach using bullets of different generic designs for the short-range and long-range applications, an approach that GG seemed to embrace. The implication was a vote of no confidence for any generic bullet design at short range.

The second issue dovetailed into the first, and also highlighted his fundamental concern about a simple empiricism providing an answer when there were so many complex variables to the problem. How did GG’s empiricism take into account the bullet’s actual terminal performance? GG had said that both the 35-caliber, 250-grainer and the 30-caliber, 200-grainer were ‘overachievers’ compared to the .375- caliber, 300-grainer benchmark. Was there a .277-caliber bullet available that fell into that ‘overachiever’ classification that satisfactorily compensated for its apparent weight deficiency?

Donny sat back and reflected. “Strategic questions instead of reactionary ones,” he thought. He sensed he was now on a potential problem-solution path with open eyes.

When Donny drove up to the 200-yard range on the following Wednesday morning, he saw GG was waiting for him. He noticed that the reloading table GG was seated at was empty except for a legal pad of paper. He also noticed that there was no rifle on the bench where GG customarily shot. “Unexpected,” thought Donny. “Hmmmm.”

GG: Pull up a stool and sit a spell.

D: No load development today?

GG: I figure your development today comes first, and I wanted to give it my undivided attention.

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Donny blinked in surprise. He didn’t know what to make of what GG had just said. Was this going to be a force-fed, high-pressure sales job?

D: All that for one little empiricism? I don’t get it.

GG: I’m not surprised. Most folks don’t. They see symbols that are being added or multiplied followed by an equal sign and assume the process is precise to the nearest third decimal. It’s what they were taught in every math class they ever took in school. Why should anything be different?

The problem is few people ever want to know the background assumptions and logic used in crafting the actual equations. They simply become fixated on pluggin’ in values and spittin’ out an answer. Computers make it worse. You rarely see the actual equations, and few folks bother to explain any background assumptions embedded in their use. Understanding the limitations to the analysis that are embedded in the selected equations is fundamental to assessing both the validity and applicability of the calculated number. The computer gives the illusion of precision. Simply put numbers into data fields and then presto-chango, instant answer.

It drove me nuts when I was working. Still drives me nuts.

I want you to be successful on your Africa hunt. Successful means maxing out the odds of recovering an animal. I think my empiricism is a simple analytical and planning tool that can help you achieve that success. That is why I am taking time to explain it to you so you can make an informed decision of whether you want to make use of it.

D: Guilty as charged. I was pluggin’ numbers into your empiricism based on our conversation last Wednesday. Suffice to say, I wasn’t happy with the numbers it spit out. But what we discussed gave me the basis for asking several questions, one of which could identify a fatal flaw in using the empiricism.

GG smiled. The Pilgrim was on the path, no doubt about it.

GG: Call me Pat Benatar. Hit me with your best shot.

D: This first question really could fall under the heading of housekeeping, as it is more of a follow-up to what you presented last Wednesday. But it leads directly to the potential fatal-flaw question. So first up, each of your three chamberings has at least two primary bullets, one for any-angle short-range shots, and a second

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primarily for long-range shots that are intended to be broadside. Am I to conclude that you believe there is no one bullet with universal application for any chambering?

GG: No, but I can see how you arrived at that conclusion. Any bullet you select should be in accordance with how you define your hunting problem and your desired terminal performance. It is quite possible that one bullet with a specific generic design can comfortably perform like you expect, based on the animal and likely impact velocities at the expected shot distances. Shots out to any hypothetical distance would only be considered if the empiricism indicated the bullet weight with its attendant impact velocity was compatible with the weight of the animal you intended to take.

D: I see how this works. The animal, impact velocity and bullet are all interrelated. The interaction of these factors needs to pass muster at all expected shot distances. If it doesn’t, such things as shot angle and shot distance may have to be modified or even limited. Bullets of a different generic design may have to be considered.

GG: Well said.

D: Second question. You said that your gel testing showed that there were two bullets that you classified as overachievers: the 35-caliber, 250-grainer and the 30-caliber, 200-grainer. Based on the wound cavity volume and the penetration results you presented, you gave the distinct impression that both of these could give terminal performance comparable with your 375 H&H’s 300-grainer. Your empiricism predicts a traditionally loaded 300-grainer from a 375 H&H would have close to 1700 pounds as an estimated game weight at the muzzle. Yet your empiricism only gives credit for an estimated game weight of about 850 pounds at the muzzle for the 200-grainer and about 1150 pounds at the muzzle for the 250-grainer. Is there a secret bullet performance jock factor that you haven’t talked about that accounts for this predicted game weight discrepancy?

Donny again saw GG sitting there, grinning at him with that stupid Cheshire cat-like facial expression.

GG: Nope.

D: So, your empiricism doesn’t take into account any benefit from superior bullet performance?

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Donny saw GG continue to grin at him. The old coot was being destroyed where he sat, yet he seemed to be having the time of his life. “The boy ain’t right,” thought Donny.

GG: Nope.

Donny couldn’t believe his ears. He felt he’d just wasted a ton of his time, basically led down the primrose path. He didn’t like it at all.

GG saw the Pilgrim’s facial expression transition from earnest to astonishment to irritation to outright anger in about the length of time it took to squeeze off a good shot. Payback for little $#!+’s snark was about to get his old a$$ whipped. Time for the explanations of why.

GG: Suppose you had no benefit of my gel test results. Would you take a 300 Winchester with ammo that had been loaded with my selected 200-grain bullet to hunt Cape buffalo?

Donny had almost shut down to the point where the question hadn’t registered. Almost, but not quite.

D: Say again?

GG: Whether you know it or not, you have privileged information on bullet performance, information that is pretty much sole source. Some might even say completely bogus. It certainly hasn’t been furnished by any manufacturer. The expanded question is this: would you be willing to put your life on the line just based on the belief that the actual test data I have presented indicated that the terminal performance from the tested 200-grain bullet shot from a 300 Winchester was comparable to the terminal performance of a 300-grainer shot from a 375 H&H?

Donnie glared at the Old Man. “Damn him.”

D: I suppose not. There are reasons 375 H&Hs are used for Cape buffalo and 300 Winchesters are not. I’m not really sure what those reasons might be, but I figure folks who do this for a living know what they are.

GG: Good answer. If you would have said yes, our conversation would have been terminated.

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The point to my question is that on the front end of defining your hunting problem, you don’t know any bullet’s terminal performance in terms of wound cavity volume and penetration for three very good reasons. First, you don’t precisely know what the impact velocity will be. As you have undoubtedly figured out, impact velocity controls a bullet’s performance, no matter what the generic design. Second, even if you did know the likely impact velocity, you have no test data that includes both wound cavity volume and penetration for any bullet. Third, even if you had such test data for a specific bullet, you have no test data for some standard by which it could be measured, in this case, the 300-grainer.

In essence, you need a place to begin in order to arrive at a reasonable solution to your hunting problem. That’s exactly what my empiricism gives you: a place to start. Nothing more.

Your fixation on chambering pretty much has you sideways. A chambering is nothing more than a launching platform to get the right bullet to the animal so it can do its job. For example, if you needed a 150-grain bullet, a chambering in .277, .284, or .308-caliber can be used. But if you need a 250-grain bullet, the .338 and 35- calibers are now in play. It’s all about the bullet weight, regardless of caliber, chambering, or over-achiever bullets. Size matters. Taylor said it over 70 years ago. Robertson is saying virtually the same thing today.

Donny sat and considered what the Old Man had just said. GG was right; he had discovered the same thing for himself in trying to resolve why Robertson had said a 150-grain bullet was lower bound for a 270 Winchester. What Robertson could have just as easily said was any 150-grain bullet from any chambering was lower bound, and that a 160 to 170-grain bullet of any caliber from any chambering was better.

D: You are right. Couldn’t see the forest for the trees.

GG: There is another aspect of this that muddles the issue, one you have no doubt seen in print and heard from your buds. I suspect that this aspect is one that you believe.

D: I’ve heard a lot of things from my buds, most of which you have tossed into the circular file over the past several weeks. What else have you locked and loaded for deposit?

GG: The notion that you can kill anything with anything as long as you hit the right spot.

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Donny rolled his eyes.

D: Come on, man! You’re messin’ with Jack O’Conner . . . AGAIN!!

GG: There are examples of outliers for just about every circumstance, like drawing to a straight flush. I have either had the privilege or misfortune to have direct knowledge of such a caliber-deficient outlier that has only reinforced the man axiom that size matters.

D: Oh lordy. . .

GG: I was on a cull hunt and shot a very healthy water buck cow. Not only did the skinner present me with my relic 300-grainer from my 375 H&H, he also presented me with what I interpreted at the time was a big shrapnel shard from that 300-grainer. When I got home and started to examine, weigh and measure my retrieved bullet, I was shocked and embarrassed to discover that the shard was actually a relic .243-caliber cup and core boat-tail bullet!

D: Let me get this straight. You have in your possession a .243-caliber cup and core bullet removed from a water buck cow that you shot with a 375 H&H?

GG: Yep. Not once, but twice with a 300-grainer.

D: Twice?!!

GG: The first shot was a front quartering. The bullet likely took out the plumbing on top of the heart. She dropped and flopped around on the ground similar to my gemsbok shot with the 35-caliber 225-grainer. I again suspect the nervous system was somehow affected. My PH was paranoid about the cow regaining her feet and bolting, so he told me to shoot her again. We had circled on the approach so the second shot was broadside into her lungs to preserve meat. Both bullets stayed in the animal. I could see the bullet from the lung shot lodged in the hide on her far side. That is the bullet I was likely presented with. I have reason to believe that the bullet from my front quartering shot was embedded in her intestinal goo. Circumstances again prevented me from a skinning-shed autopsy.

D: So, you don’t know where the .243-caliber bullet and your 300-grainer bullet were found?

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GG: Yes and no.

D: Come on man! Either you do or you don’t!!

GG: As luck would have it, I asked for the cow’s hide as a flat skin. When I got it back, I found six patches on the reverse side of the hide that had likely been installed to reinforce or fix holes made by bullets.

D: Six?!

GG: Three could be attributed to my 375 H&H; two entrance and one that tried to exit after passing through the lungs. The other three I attribute to cull hunting with a .243-caliber bullet. One of those patched holes inferred to be associated with a .243-caliber bullet was within an inch of the entrance hole for my lung shot. The other two were low on the rear flank as if someone had tried to stop her as she ran away. Pure speculation, but that is why I answered yes and no.

D: But you say there were two holes in the hide associated with a lung shot?

GG: Yes. A skinner is not gonna go fish for a bullet. It has to be obvious and easy. With a 300-grainer into the lungs near the same entrance point as the suspected, .243-caliber bullet, I daresay both were obviously easy to find.

I speculate that the .243-caliber bullet was a 100-grain cup and core shot from a 243 Winchester with a muzzle velocity of about 2960 fps. The bullet that was handed to me is highly deformed. If the shot had occurred at say 90 yards, the bullet’s impact velocity would be on the order of 2800 fps. Such an impact velocity could be in keeping with the condition of the retained bullet I observed. There was no indication on the far-side hide that it had passed completely through the boiler room. The .243-caliber entrance hole was apparently not large enough to prevent the self-sealing of the hide that water bucks are noted for.

D: (Smirking) All speculation.

GG: Admittedly. And heavy duty at that. However, the fact remains that a 400-pound water buck cow was apparently doing quite well with a .243 caliber bullet likely lodged somewhere in her boiler room, and others lodged elsewhere. That reality is tough to ignore. At an impact velocity of 2800 fps, the empiricism gives an estimated game weight of about 200 pounds. Both the empiricism and the cow indicate to me that a 100-grain bullet is a poor choice.

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Donny sat there silent and frowning. “All circumstantial evidence,” he thought. “But damn if there isn’t a ton of it.”

GG: There is another reason why I think size matters. The heavier the bullet, the greater the punch it has on the animal. The greater the punch, the greater the potential to debilitate the animal.

D: Taylor’s knock-out value?

GG: Not really, but conceptually close. Taylor applied his concept to head shots with solids. His basic equation is bullet weight times muzzle velocity times caliber divided by a constant. A fellow by the name of Hatcher decided that instead of a bullet’s diameter, the bullet’s caliber end area should be used to assess a bullet’s ability to stun or stop. Hatcher developed an empiricism to determine what he termed “relative stopping power” based on a bullet’s caliber end area and various bullet factors of his own conjuring.

Of the two, I think Hatcher’s approach is conceptually more applicable for explaining how expanding bullets can produce a debilitating effect on the body because end area is used. The magnitude of the displacement-induced blood compression wave created by a bullet as it passes through the body is related to the bullet’s volume. End area rather than diameter becomes more relevant in a direct volume determination.

You can envision the effect of end area on a fluid compression wave by watching how an Olympic-caliber diver enters the water at the completion of a competitive dive. Compare that to how my fat old a$$ would enter the water if I did a cannonball. The Olympic diver kindly wedges himself into the water by trying to turn himself into as much of an ice pick as he can. Looking at the water surface after a good ‘riff’ entrance, it’s difficult to believe that a 180-pound anything could cause so little disturbance. If this same diver decided to emulate my cannonball by increasing his frontal area, the wave slosh over the top of the pool could potentially carry away the judge’s table.

In my view, I consider the magnitude of the blood compression wave generated by a bullet’s passage through tissue as its punch, and the magnitude of that punch is directly related to its ability to initially debilitate, or stagger the animal. In the words of my PH friend, this concept of punch is the ability of the bullet to ‘make the animal sick’, independent of the subsequent effects of the actual bullet hole, blood-shot

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tissue, and any hydrodynamic shock. The ability of my 350-grainer to stagger my buffalo is the context in which he used that phrase.

The displacement wave in water created by a super tanker is greater than the one created by a bass boat because of the volume of fluid that is displaced. If you think of a .375-caliber, 350-grain bullet as a supertanker compared to a .243-calber, 100-grain bullet as a bass boat, the greater blood displacement volume caused in the tissue by the 350-grainer causes a greater, more forceful blood compression wave. The bullet’s weight, coupled with its end area, is directly related to its displacement volume. The bullet’s displacement volume and impact velocity affect the magnitude of the blood displaced and the resultant compression wave, with more bullet volume and impact velocity producing a greater debilitating effect.

D: So, because a bullet’s weight and end area are directly related to its volume, a bigger bullet is better in terms of both more momentum and its ability to generate a bigger blood compression wave ‘punch’. A bigger bullet weight is better.

GG: Exactly. Proper man-speak.

D: So, is this notion of bigger is better embedded in your empiricism?

GG: Yes. I have it conceptually written it down so you can see how it has been derived.

GG showed Donny what he had written on the tablet:

GG: This empirical equation is for estimating plains game weight, in pounds, that can be taken by any generic bullet by simply knowing its weight, in grains, and its impact velocity in feet per second. The answer you get is only an estimate, and could vary at least 15 percent either way. This empiricism should not be used for dangerous game.

What you see in this mathematical representation are the conceptual components I considered valid at arriving at the estimated plains game weight. The combined effects of the bullet’s impact momentum, caliber end area and sectional density are

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multiplied by an empirically derived bullet factor that I will subsequently explain. I am calling the combined effects of the bullet’s momentum, caliber end area, and sectional density a punch factor.

Bullet impact momentum multiplied by bullet caliber end area is a simplified Hatcher approach. I say simplified because Hatcher correctly converted bullet weight into bullet mass to obtain momentum in precise physics terms. He also used bullet shape factors. I do not. Like most folks in the industry have done, I have bastardized the physics by simply defining momentum as the bullet’s weight multiplied by its impact velocity.

I have multiplied this simplified Hatcher stopping power by the bullet’s sectional density. A bullet’s sectional density is an imprecise way of assessing its length-to-diameter ratio. In general, the greater a bullet’s sectional density, the longer it is for any given caliber. A greater sectional density is better, meaning a longer bullet for any caliber is better because longer means more bullet volume.

As I have indicated, I believe a greater bullet volume produces a greater debilitating effect in terms of ‘punch’ as well as the potential for inducing hydrodynamic shock. As I have also indicated, hydrodynamic shock is kindly luck of the draw.

There are far more tangible benefits associated with increasing the volume of a bullet, particularly when considered in terms of increased bullet length. First, the increased length is a reservoir of sacrificial bullet weight should the impact stress be high enough to strip away some percentage of the bullet during passage through tissue. This weight reservoir also provides additional material to maintain some degree of mushroom formation.

Most folks would likely be skeptical of my assertions that stripping weight from a bullet doesn’t really affect its penetration as much as what happens with the rate and extent of its mushroom formation. Indirectly taking a bullet’s length into consideration as a weight reservoir should at least make momentum advocates feel good. Should some weight be stripped away during formation of the mushroom, a bullet with a high sectional density still has some reserve weight to conceptually maintain momentum for penetration.

Second, this increased length likely provides some added measure of stabilization to the bullet’s trajectory through the tissue. A longer bullet shank provides weight to

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conceptually help counterbalance any tipping forces and to serve as a backhanded rudder or sailboat center board as it traverses through the goo created by the bullet.

Finally, I believe any additional bullet length is beneficial because it also provides a potential reservoir for shrapnel. You have heard me repeatedly say that my testing has shown that this shrapnel is beneficial in producing wound cavity volume and enhanced drainage passageways for bleed-out.

GG then wrote a revised equation below the first:

GG: This new equation form is the same as the first one, except that I have mathematically defined momentum and sectional density.

If you plug in a bullet weight in grains and an impact velocity in fps, it’s a gawd-awful big number. Because this is an empiricism, you really don’t need to pay attention to the units, like changing grains to pounds. The 1,000,000 in the denominator is an arbitrary, convenient conversion factor that takes care of the units and reduces the calculated number down to something I can wrap my head around, units be damned.

You can see that the areas will cancel and you are left with (GG wrote again):

D: And the bullet factor? Is the hand waving gonna get more extreme than what you have presented thus far?

GG: That’s up to you to decide. In initially developing this empiricism, I was trying to conjure an improved Taylor or other lethality index that made better sense to me. I got as far as (GG pointing to the tablet):

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I can remember sitting and staring at that relationship thinking “So what? A conceptual punch factor. It’s just another ranking system number that really doesn’t help anybody quantitatively define his hunting problem.”

I had Robertson’s book at the time and a similar book by Boddington for shots on North American game. These books’ contents are unusual in that both authors actually come out and declare chamberings and bullets that they believe should be considered and are even preferred for taking a particular species. Another book entitled Aagaard’s African Adventures by Finn & Berit Aagaard, published by Safari Press, chronicled hunts and gave clues about successful chamberings and bullets used.

I asked myself the question: could the punch factor, PF, of [(W)² x (V)]/1,0000,000 somehow be correlated to what these authors believed were appropriate chamberings and bullet weights for the referenced animals?

I assessed there were two major problems to any potential correlation. First, and the most obvious, was I had limited-to-no shot distance information referenced by these authors, other than what an occasional long shot might be. Therefore, I couldn’t precisely determine impact velocities. Second, there was the special interest fog factor about a ‘best’ bullet. Everybody has his favorites. Even implying that a cup and core bullet gave the same terminal performance as a solid copper bullet would get most folks sideways. As exemplified by my ‘over-achiever’ bullets’ test results, a ‘one size fits all’ is really not applicable for anything, let alone hunting bullets.

D: So how did you go about cracking those two nuts?

GG: I decided the first issue about distance and resultant impact velocity was technical. If I couldn’t resolve that, there was no need to worry about the second. So, I chewed on the distance-and-related-impact-velocity issue for a couple of days.

I finally resolved it in a way that should be familiar to you by now: I used assumed maximum and minimum distance scenarios where applicable, and a typical 100-yard average shot distance when I had no clue.

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D: Why not your 135-yard average?

GG: When I was fiddling with this, I had taken only one trip to Africa. I certainly had no shot-distance data from which to base a reasonable average shot distance.

D: So, what were your minimum and maximum shot distances?

GG: Fifty yards for a minimum and 300 yards for a maximum, which I since believe are reasonable. I also worked with distances of 150 and 200 yards.

D: What was your actual methodology?

GG: The equation I had conceptually derived is a qualitative punch factor multiplied by an unknown bullet factor that equals a known animal weight.

GG began to scribble again on his pad.

GG: The (W)² x (V) divided by 1 million is my punch factor. The BF is, of course, the bullet factor. The EPGW is the estimated plains game weight. I solved that equation for BF.

GG again scribbled on his pad.

To make things simple, I assumed that all generic bullets have the same bullet factor because Robertson would first call out bullet weights and give no specific bullet types until he talked about applicable chamberings.

I first went to Robertson’s book and read what he had to say for an animal of interest concerning recommended chamberings and bullet weights. I interpret he typically qualitatively ranked his recommendations as ‘minimal’, ‘better choice’ and, for lack of a better category, ‘slam dunk’. For example, when he talks about hunting kudu in the thick stuff, his ‘minimal’ bullet weights are 175, 180, and 220

grains for chamberings of 7x57, 308 Winchester, and 30-06, respectively. His ‘better choice’ bullet weights are the 250-grainers for the 338-06 and 35 Whelen. His ‘slam dunk’ bullet weights with attendant chamberings are 286-grainers for the 9.3’s and 270 to 300-grainers for the .375’s.

I researched maximum animal weights for plains game of interest. I figured that PHs would pretty much select prime, mature bulls or rams to be harvested, so my EPGW was 90% of the upper-end weight of a typical bull or ram. For example, the typical weight for a kudu bull ranges from about 420 to 600 pounds. Ninety percent of 600 is 540 pounds.

I selected multiple chamberings with assorted bullet weights from Robertson’s ‘minimal’ and ‘better choice’ categories for selected plains game of interest. I looked up representative muzzle velocities for these selected chamberings and bullet combos. I assumed that the bullets were all flat-base spitzers and identified representative BCs for each. I used published muzzle velocity and bullet BC data from ammo manufacturers in my personal ballistic software program to estimate impact velocities out to 300 yards. I then had the information I needed to run a series of calculations to determine ranges of BFs.

As an example: for the kudu, one of Robertson’s ‘better’ choices is a 35 Whelen with a 250-grainer. I selected an arbitrary range 100 yards to calculate a BF. For a muzzle velocity of 2475 fps, the impact velocity for a 250-grainer at 100 yards is about 2300 fps. This equation would look like this (GG again scribbling on the legal pad):

I did at least one calculation for each ‘minimal’ and ‘better choice’ chambering and recommended bullet weight at arbitrary distances that ranged from 50 to 300 yards, depending upon the animal, terrain, and vegetation associated with its habitat. For the animals in Robertson’s book, I did 53 calculations associated with 10 animals ranging in size from a springbok to an eland. I added up all the calculated BF’s, then divided by 53 to obtain a simple average. That average is 6.5.

I did the same evaluation-and-calculation methodology for the hunting information found in Aagaard’s book. I did 31 calculations for 13 different animals. The average BF is 8.6.

I did the same evaluation-and-calculation methodology for the hunting information found in Boddington’s book. However, I assumed the animal weight was an average of published maximum and minimum weights, because no PHs would typically be identifying the animal to be shot. I did 30 calculations for 14 different animals. The average BF is 7.7.

The simple unweighted average of all three BF’s is 7.6. The simple unweighted average for the Africa animals based on information in Aagaard’s and Robertson’s books is 7.55. Based on all of the above, I selected a BF of 7.5, a nice, easy number to remember.

Donny stared at GG, the snarky smirk on his face plainly visible.

D: BF’s? More like BS. Sounds to me like you have once again tortured numbers to confess to something they know nothing about.

GG: I understand completely. When I decided on a value of 7.5, I immediately began the validation process by doing calculations for EPGW at what I consider the extremes of the ballistic world: a 22-short rim fire with a 29-grain bullet at 1132 fps and a 50-77 buffalo rifle with a 450-grain bullet at 1260 fps. I got an EPGW of 7 pounds for the 22 short, indicating it would be an excellent chambering and bullet to dispatch rats or feral cats. I got an EPGW of 1913 pounds for the 50-77, indicating that this chambering and bullet would not embarrass anyone when hunting bison. It also points out the prevalent demand from the buffalo hunters of the time for ‘more gun’. That demand produced the 50-90 and the 44-90, both chamberings with heavier bullets capable of taking an animal weighing over 2500 pounds. You can look them up and do the math if you like.

Good results at the extremes of any empirical analysis are a litmus test for the applicability and usefulness of the empiricism. If the empiricism produces good results at the extremes, it likely can produce good results in the middle, so-to-speak. As I said previously, Matunas’ empiricism results in estimated game weights only one-third of what my empiricism estimates for the ‘extreme’ exemplified by buffalo rifles.

The true litmus test for me, however, was to go back and run calculations for Robertson’s ‘better choices’ for typical plains game at a variety of distances. For the 35 Whelen shooting a kudu with a 250-grainer at a muzzle velocity of 2475 fps, the EPGW at 135 yards is about 1050 pounds, and the EPGW at 250 yards is about 960 pounds. Both answers comfortably indicate ‘enough bullet’ and ‘enough gun’.

Over the last decade I have done literally hundreds of check calculations based on what I have seen on hunting shows and my own ‘what ifs’. The empiricism has either validated the bullet weight with attendant chambering or at least indicated that the combination was reasonably close except for one instance: the eland. According to my empiricism, Taylor was badly under-gunned with his 350 Rigby magnum and 225-grain bullets. Eland bulls typically weigh between about 900 to 2000 pounds. But two eland bulls fell in quick secession to his 350 Rigby magnum on slightly rear quartering shots at about 200 yards. The empiricism indicates an EPGW of about only 760 pounds for that scenario.

I have a friend who took an eland at about 175 yards with a 212-grain bullet from a 300 Winchester at a muzzle velocity of about 2900 fps. The empiricism only indicates an EPGW of about 875 pounds for that scenario. For what it’s worth, Matunas’ empiricism would have also under-predicted the weights for both of these chamberings.

Ain’t no empiricism that is perfect. There are always outliers. That being said, I have checked enough actual hunting applications over the years to believe that for most circumstances, my empiricism can give estimated game weights that can be characterized as representative, reasonable, and prudent. If there is a bust, I have so-far found it will be an under-prediction of the animal’s weight, just as with the eland. With thousands of dollars of trophy fees potentially at risk, an under-prediction can be a good thing. It typically either forces a change to a heavier bullet or a change in hunting strategy to increase the odds of recovering an animal.

D: I tinkered with your empiricism based on what the PHs in Harrisburg essentially gave as their first choice for a kudu chambering and bullet. I never calculated specific EPGWs because I never asked what shot distances were typical. The EPGWs at the muzzle were all okay for at least 600 pounds except the 308 Winchester with the 165-grain solid copper bullet. You have already given what I can now conclude is a reasonable answer for why that chambering and bullet was included.

GG: I think the 308 Winchester with the 165-grainer is an excellent example of a reasonable thought process when the EPGW is shy of what you think you need. You consider alternatives to mitigate the implied risk. You can consider

limiting shooting distances in conjunction with a premeditated target like the heart. You wouldn’t be just aiming at the shoulder any more, you would be aiming at a specific spot on the shoulder to take out the heart. Aim small, hit small. You can consider limiting the shot to a broadside or selecting the generic bullet type that enhances ‘perforate to ventilate’. In short, you will be revising your hunting strategy to get the potential risk of losing an animal back to a level you considered reasonable.

D: I suppose my biggest concern was that the chambering I wanted to use wasn’t going to work. I never realized that focusing on the generic bullet or a heavier bullet could potentially provide some relief. Going with a heavier bullet has an implied negative connotation due to reduced velocity. But as long as I am in an interpreted impact velocity sweet-spot range for a particular generic bullet, a reduced impact velocity probably isn’t of much technical concern. Losing velocity with a heavier bullet is probably more of a psychological concern than anything. Even with the reduced velocity, the momentum with a heavier bullet is greater, so therefore the punch is greater.

GG: (Smiling) Bingo. It’s all about technical merit, style points not required.

D: (Smirking) Yeah. But a bunch of folks are going to claim that a bullet factor that is the same for all bullets short-sheets the advantages of each specific generic design. Essentially, what you are saying is there are no overachiever bullets.

GG: Ah. My second problem. I consider that issue more political than technical. The solution is actually pretty easy.

There is a pattern to using my empiricism. You first determine the weight of the animal you intend to take. Then you check to see if the bullet weight with the chambering you would like to use will work at some assumed shot distance. If it does, you then match the likely impact velocity of that bullet weight with impact velocity sweet-spots of the generic bullets. Matching up your likely impact velocity with the impact velocity sweet-spots is the basis for your bullet selection.

Robertson essentially follows the same pattern. He already knows the game weight and likely shot distance. Through experience, he then recommends bullet weights followed by attendant chamberings. Only after he recommends the chamberings does he talk about bullet specifics, identifying bullets he knows that will work based on experience. He hasn’t referenced impact velocity, but he just as easily could have. Use of the empiricism mimics Robertson’s presumed thought process.

As an example, for hunting kudu in the thick stuff, I believe he recommends a 250-grain bullet for both a 338-06 and a 35 Whelen. He doesn’t say a 225-grain solid

copper bullet can be substituted for a 250-grain bonded-lead core bullet, nor does he say a 300-grain cup and core bullet could be substituted for a 250-grain dual- lead cell bullet. He focuses only on the bullet weight. Once he stipulates the weight, he provides recommendations for the chambering, then the bullet’s generic design.

The primary question the empiricism asks is “Do you have enough bullet to conservatively take the animal under consideration?” The secondary question the empiricism asks is “Do you have enough gun to get the bullet of the right weight to the animal so it can do an effective job?” That’s where chambering and velocity come into play. Most folks are inclined to believe that the chambering with attendant muzzle velocity is the more important question, kindly bass-ackwards to what the empiricism emphasizes by squaring the bullet weight.

D: How well I know. I was ate up with maxing out velocity, thinking that the highest possible was the key to success. I am beginning to see that the bullet’s impact velocity in conjunction with its generic design is the key to terminal performance of my choosing.

Even so, your empiricism still doesn’t sit all that well with me. First of all, it subjugates my judgment-and-experience data set. Second, the substitute for that judgment and experience is what some will still call a formula with no firm grounding in science and no documented or demonstrated performance track record. Third, and probably most damning, it is linked by nothing more than speculation to observations and experiences of folks I’ve never even heard of. Why should I believe it?

GG: Believe what you choose to believe. I view the empiricism as a risk evaluation and hunt planning tool. You could use it to assess if your 270 Winchester with any bullet and attendant limitations was a reasonable choice as a chambering for hunting your selected Africa plains game. Both using it and how you use it is up to you.

From my perspective, I’ve done enough check validations of my empiricism through the years based on TV hunting shows to prove to myself that it can reasonably predict hunting reality outcomes. As with the eland, I believe the worst criticism of its use is that it can occasionally underpredict the estimated game weight. There are far worse things that could be said about any analytical approach to solving a problem besides ‘careful’.

D: Maybe so. But the folks you cite as the experts you used to conjure BF are not here to agree or disagree with what you have done. Suppose those three experts were here right now listening to all this, and I asked you to give me a recommendation. What would you tell me?

Donny saw GG wince. He obviously didn’t want to respond.

D: Just spit it out. You won’t be quoted.

“Quoted; no. Cursed; more likely than not,” thought GG. As had occurred countless times throughout his professional career, he was being asked to give folks what he believed was needed instead of what they wanted.

GG: For plains game hunting in Africa, first define the hunting problem on your terms like we discussed. Use my empiricism to select a bullet weight with attendant chambering that comfortably accommodates the maximum weight animal at the maximum likely shot distance.

You have a 270 Winchester. I can almost guarantee that the animal weight you calculate with my empiricism and off-the-shelf ammo will be less than the weight of a trophy kudu bull, regardless of hunting scenario. You then have three choices: take some degree of an elevated chance at losing an animal with your 270 Winchester and off-the-shelf ammo; reload your own ammo with a heavier bullet; or use a different chambering that can comfortably deliver a bullet of sufficient weight that satisfies the empiricism’s estimate.

If you choose to use your 270 Winchester with off-the-shelf 150-grain ammo, the hunting strategy likely becomes one of risk mitigation. You take only broadside shots at distances compatible with your system’s ammo accuracy and shooting position. Your target should be the heart, not just somewhere on the shoulder. Study Robertson’s book and memorize the precise spot on the animal you want to hit. Think ‘aim small, hit small’. Use a bullet noted for its demonstrated ability to penetrate, thinking that the least you want to accomplish is to ‘perforate to ventilate’. You must come to grips with the reality that you will likely have to pass on some shots because they are beyond the range where you are confident you can take out the heart.

If you decide to reload and use a heavier bullet with your 270 Winchester, make sure your barrel twist is compatible with your selection. You may want to consider

throating your current barrel to better accommodate the greater length of a heavier bullet.

If you decide a different chambering is the preferred path, consider converting your rifle to a switch-barrel system. You can keep your current stock, scope, action and trigger, but can screw on a different barrel of a different caliber and chambering. For example, you could screw on a barrel chambered in 280 Remington, 30-06, 338-06, or 35 Whelen. All those chamberings allow you to use your current bolt. You can easily change barrels by yourself, but would need a gunsmith to set up your rifle for a switch-barrel application and then chamber the new barrel to fit.

Regardless of the choices you make, practice, practice, practice, practice. Dry fire from sticks daily for at least a month prior to the hunt. If some of your shots could be from a bipod, either seated or prone, dry fire those for at least a month as well. Live fire from all expected shooting positions at least once a week for a month prior to the hunt. Live fire at a more frequent basis if your targets indicate poor technique. Deviations from these suggestions increase the risk of an unrecovered animal. The greater the deviation, the greater the risk. Regardless, $#!+ happens.

Donny sat there frowning. Although he suspected there was going to be no relief from the limitations of his 270 Winchester and typical off-the-shelf ammo, the Old Man had finally said so. Politely. For him, likely over-the-top PC. But the Geezer’s PC didn’t mask the sting of his final dispensation of reality, reality that Donny already essentially knew to be true. The Old Man had been his final hope for the mental prophylactic he had been seeking, rogue testing and tortured numbers be damned. Indeed, $#!+ happens. He had just been forced to focus on that prospect and implications of its conceptual reality.

The alternatives were no better. He absolutely did not want to borrow a rifle. He didn’t want to fool with reloading nor the hassle and complications associated with a switch-barrel conversion. His knee-jerk reaction was ‘none of the above’, and that officially got him sideways.

Donny simply nodded to GG, got up and went to his truck. He was so self-absorbed with his disappointment and a self-imposed ‘no way out’ pity party that he abandoned any semblance of civility. He had finally had ‘enough’, accepted manners and decorum be damned.

GG watched the Pilgrim go. Disappointment was trying to morph into anger through the portal of betrayal. He wouldn’t let it happen. “I told him to take the best

and leave the rest,” thought GG. “Can’t help it if he didn’t take any of it. But the snarky little $#!+ could have at least said thank you.”