Effective Game Killing - Part 2 By Nathan Foster
Putting the information together
The speed of incapacitation or what we call fast killing is one method for which the hunter is able to measure a cartridge’s effectiveness on game in comparison to other cartridges. It must be remembered however that the word effective by definition in this instance describes the ability of the cartridge to achieve fast incapacitation and has no maximum limit to power. An efficient cartridge on the other hand describes the ability of the cartridge to kill using the minimum necessary power. I do not believe that efficiency should ever be put exclusively ahead of effectiveness (fast killing).
With regards to shot placement versus mechanical wounding, a good example of this can be found in the .243 Winchester. At ranges beyond 200 yards and especially at ranges of around 300 yards the .243 can produce slow kills with rear lung shots due to narrow wounding. By bringing shot placement forwards to the line of the foreleg or 1 to 2” further forwards of the line of the foreleg, a fast kill can be obtained via direct destruction of the autonomic plexus (nerve ganglia between the heart and lungs). If however, such shot placement cannot be guaranteed, a change to (for example) the .270 Winchester, will ensure greater internal wounding with rear lung shots, effecting a faster kill.
Shot placement, as just described with the .243, can of course negate the need for hydrostatic shock or immensely wide wounding as a result of hydraulic shock. An accurate but low velocity rifle/ cartridge combination capable of striking the autonomic plexus of game in a reliable manner will anchor game just as quickly as a cartridge capable of producing hydrostatic shock with rear lung shots. On the other hand, the hunter is not always presented with the perfect shot. Therefore, the more effective a cartridge is regarding wounding, the more forgiving it can be with less than ideal shot placement.
So far we have discussed Hydrostatic shock in great detail while only touching on hydraulic shock. Like Hydrostatic shock, hydraulic shock is increased at high velocities and has similar cut of points at different velocity parameters. Looking at one projectile as an example, the 130 grain .270 Winchester Interbond expands to a diameter of between 13 and 17mm at high impact velocities. The wound channel this creates through vitals is around 50 to 75mm (2-3”) in diameter. This is what I call disproportionate to caliber wounding and it is very effective. As velocity falls to 2600fps, wounding tapers off slightly, the internal wounds being around 25-40mm (1-1.5”) in diameter.
As velocity falls below 2400fps, wounding gradually becomes proportionate to caliber, noticeably so at 2200fps. Between 2200fps and 2000fps (450 to 575 yards), the Interbond projectile expands to a diameter of around 8 to 9mm, creating a wound channel of around 8 to 9mm, resulting in slow bleeding and therefore, if the CNS is not destroyed, a very slow kill.
To regain disproportionate to caliber wounding at low velocities, the projectile must be capable of shedding a large amount of its bullet weight, up to 90%, allowing a cluster of fragments to create wide internal wounding to increase the speed of blood loss for fast killing. The term I use for this is “mechanical wounding” Here again my research deviates from the usual literature. And with the arms industry currently rushing to produce small low powered assault rifle cartridges that boast magical killing power, industry players are themselves having to more fully explore these subjects while terms like temporary wound channel lose even more of their sparkle.
Although bullet weight loss is critical for fast killing at low velocities, this does not mean to say that a .22-250 loaded with a varmint bullet will produce clean kills with chest shots on medium game. The cluster must also be matched to game body weights, having optimal density and momentum.
Although a frangible bullet is able to produce wide wounding due to mechanical destruction alone, hydraulic shock also occurs at much lower impact velocities than a controlled expanding bullet. As suggested earlier, Hornady research suggests that blood pressure spikes in the brain cause coma, resulting in (as much as possible) a painless death. Whether from a hydraulic or mechanical perspective, wounding of fragmentary bullets is much higher than that of controlled expanding bullets at low impact velocities, providing the cluster has sufficient density and momentum relative to game body weights.
During TBR testing, a packet of vintage Winchester Western .30-30 160 grain hollow point ammunition was tested on medium game animals. This is perhaps the earliest example of a frangible bullet. As best as could be determined after extensive research, it could be concluded that historically, the .30-30 was possibly not standing up to its design premise and that a frangible bullet was adopted to increase wounding capacity.
The .30-30 160 grain soft point load was intended to produce wide wounding and fast kills as a result of the newly discovered powders which generated exceptionally high velocities (for 1894). This was a complete turnaround from past terminal ballistics research which had proven that the bigger the bore, the wider the wound. The .30-30 (.30 WCF) loaded with a controlled expanding bullet is not a great deal more emphatic than the .45/70, the .45/70 having already proven to be an emphatic killer. Western’s hollow point load was introduced a little while after the soft point.
While the frangible .30-30 bullet would have been acceptable for use on the smaller deer species of the U.S, one has to wonder how this load fared on the Grizzly bear featured on the ammunition box of the .30-30 hollow point ammunition. The results would most likely have been disastrous. About 200 grains is a safe minimum frangible bullet weight for these body weights.
Frangible bullets are important at low velocities, especially at long ranges. A frangible bullet capable of rendering a wide wound in the absence of disproportionate to caliber wounding (high velocity) helps ensure fast bleeding for fast killing.
As a short recap, with ideal shot placement and utilizing a cartridge with sufficient power to penetrate the vitals of intended game, we can destroy the CNS and cause an instant kill - however this is often idealistic and unrealistic. With less than ideal shot placement, high velocity can initiate hydrostatic shock and hydraulic wounding to help ensure fast kills out to ordinary hunting ranges (300 yards). In the absence of high velocity, a fragmentary projectile can ensure fast killing via hydraulic shock and wide (mechanical) wounding, producing fast bleeding. In all instances, bullet weight and bullet construction need to be matched to the job at hand.
Please try to remember the following for medium game hunting:
Choose light and stout or heavy and soft.
A light but stout projectile can deliver hydrostatic shock while having the tough bullet construction needed to deliver sufficient penetration. However this has a range limitation, usually of around 300 yards, after which, careful shot placement is required. This can be counterproductive in cross winds. Nevertheless, this method is often the most effective for minimizing meat damage on lighter medium game at ordinary hunting ranges (out to 300 yards).
When chest shooting heavy game, a heavy but stout controlled expanding projectile driven as fast as the shooter can manage produces the fastest possible killing. As O'Rourke said, use enough gun.
Use enough gun. The .338 Win Mag and controlled expanding 225gr Nosler Partition can be put to great work on bear. That said, shot placement is a key factor to effect extremely fast killing.
A heavy yet soft and frangible or partially frangible projectile (loses some weight) may not deliver hydrostatic shock very far depending on game body weights, but providing the cluster is dense enough, it will be capable of rendering deep, broad and highly traumatic wounding across a wide range of body weights. Good frangible bullet designs can continue to produce mechanical wounding and a measure of hydraulic shock down to impact velocities of 1600fps with some exceptional projectiles continuing to produce excellent performance down to velocities as low as 1400fps.
For those wondering about the middle ground between light and stout and heavy and soft, there are certainly some good bullet designs on the market. One of the best middle ground bullets is the Hornady SST, a semi frangible bullet design that tries to retain some weight for penetration. A specific example is the 7mm 162 grain SST which is effective on Red/Mule deer at close ranges (adequate penetration) yet is capable of producing wide wounding at extended ranges (around 1000 yards in the 7mm Remington Magnum).
On the other hand, we do have to be a bit careful with the middle ground. For example, the Nosler Accubond has core bonding in an attempt to toughen the bullet but is also designed to be fast expanding and is generally available in mid weights such as the 140 grain .270 Winchester bullet. This particular load works extremely well on mid-sized deer at ordinary hunting ranges however, the Accubond can suffer when pushed to the extremes. It can be too stout for low velocity work yet too soft for tough game. In this regard, we have to be careful as to how we use a ‘general purpose’ bullet design.
You may wish to take a note from the Taoists and choose the middle ground so as to be prepared for any contingency, however if you fail to fully understand the limits of your cartridge versus your intended game, you may choose something which is neither fish nor fowl and does a generally bad job within the role you have chosen for it. For example, you may load the .375 caliber 260 grain Accubond for an African trip. And while this works exceptionally well on some larger bodied game, you might be in for a world of hurt if you try to tackle a cape buffalo with this bullet and find that it completely runs out of steam before reaching vitals. Please use my cartridge knowledge base and books to obtain a deeper understanding of how each of the manufacturers bullets work, their strengths and limitations.
I have been continuously researching wounding for most of my life and the results and variables are far greater than can be covered in one short document on effective game killing. Nevertheless a rudimentary understanding of the fundamentals of game killing, wounding and speed of killing can serve as a useful platform before continuing on and exploring my in-depth research as well as your own field observations.
Looking forwards, we seem to be heading towards some very strange extremes. In one camp, we have hunters looking for any excuse to use low powered cartridges in short barreled suppressed rifles and or AR-15 platform rifles while in the other extreme, a few gun companies continue to work towards barrel destroying ultra-velocity magnums. Either approach can cause a great deal of problems for hunters. Ultra-fast cartridges can cause shallow penetration at close ranges and ironically still lead to disappointment when bullets still display vast drop and wind drift at truly long ranges. The fastest cartridges may have a barrel life of less than 600 rounds, 200 of which may be used up during load development.
Modern low powered cartridges are simply that - low in power. You do not have to be rocket scientist to figure this out. If the bullet is the same weight as a 7.62x39 or .30-30 bullet and going at the same speed, it will produce the same results regardless of how it is labelled. To recap from earlier, the slower you go - the wider you need to go (think .45 etc) or the more the bullet needs to shed weight if we are seeking optimum killing performance. This also ties back into the problem of forcing people to use homogenous copper bullets for environmental reasons. Low power and stout bullets simply don’t work that well together unless the projectile has specialized design characteristics.
If the bullet is to shed weight it may need significant weight to begin with (depending on the size animals you are hunting) in order to achieve reliable penetration. Also remember this; there is little that can be done now that has not been done before. There is no new magical cartridge that offers twice the killing power with half the energy. Projectile designs are certainly advancing in some areas however there are limitations as to how far this can be taken.
As a hunter, the primary factor that must be foremost in your mind is animal welfare, not how short or light your rifle is or whether it can handle a thirty round magazine (even if you are a culler). Factors such as recoil or cost should also be treated as secondary to the primary goal of a fast effective kill.
As far as new cartridge designs go, please try to refrain from becoming caught up in hype. The physics of wounding are really rather straight forwards once you have a full understanding of the basics. The trick is just that - to understand the basics. Once you have understood the fundamentals of game killing and how cartridges behave in general, then you can move forwards and not be misled by marketing fabrications.