💀 Quarry: What kills’em dead – the Mechanics of Killing

[JungleShooter]

Quarry: What kills’em dead – the Mechanics of Killing


This thread is PART (1) of a four-part series (cf. below for links to the other threads).


What kills is a Permanent HOLE in the quarry – nothing else

We use projectiles (pellets and slugs) to kill quarry. But what exactly kills a shot animal (apart from septicemia)?
We say we want to “dump energy” and getting more “energy transfer” – and we know of course that it’s not the energy in and of itself that destroys and kills – we can fire a bullet into a bucket of water and the water absorbs all of the bullet’s energy – but nothing gets destroyed!

So, it’s not more “energy” that we want inside of the animal: It’s more destructive work done by the energy inside of the animal!

• The destructive work of a projectile is slicing and crushing (destroying!) the quarry’s tissue (penetrating trauma). The crushed tissue causes a permanent hole, the permanent wound cavity. And scientifically, medically, what kills is a permanent HOLE in the quarry – nothing else. (cf. sources below*)

• There is also non-destructive work done by some of the energy: The momentary stretching of the neighboring tissue along the permanent HOLE, resulting in a temporary wound cavity. At airgun velocities this temporary wound cavity normally does NOT cause any damage. However, in non-elastic “clay quarry” and “play-dough animals” the temporary wound cavity looks permanent and very impressive (esp. to potential subscribers). But clay and play-dough are non-elastic and thus greatly exaggerate the effects of a projectile – the quarry’s tissue is elastic and the only real damage is the permanent HOLE.

And to at least mention the “hydrostatic shock,” even disputed among high velocity ballisticians: We simply admit that the “hydrostatic shock” is not a factor at the low velocities of our AG.




For the HOLE to kill – it must be in the right place in the quarry

There are two main ways of how the crushed tissue of the permanent wound cavity leads to death (aside from septicemia/ infections, or starvation due to a destroyed jaw):

(1) The function of body parts immediately necessary for survival is hindered, i.e.:
• Brain and spine (central nervous system CNS) are needed not only for voluntary coordinated use of extremities but also for the involuntary control of essential internal body parts (heart!), i.e., “living”.

• Heart, lungs, and the major arteries/veins are needed to transport oxygen to the brain which is essential for its functioning.


(2) The crushed tissue of various organs and muscle tissue includes arteries/veins that are now open and are bleeding (hemorrhaging). The more blood is lost, the less oxygen arrives at the brain which it needs for its functioning (“living”!). And if the blood is lost rapidly, the quarry can be incapacitated due to the quick decrease in blood pressure.

A HOLE is only deadly if it is in the right place. Therefore, shot placement is first!




The projectiles that make a Better HOLE in the quarry are –– larger, faster, bulldozer-nose, expanding projectiles

After addressing shot placement(!), we can try to improve the permanent wound cavity as follows:

(1) The wider the diameter of the projectile (pellet or slug) the wider the diameter of the HOLE. And more crushed tissue is better.
➔ Therefore, a larger caliber can be an advantage. Or a projectile that expands upon impact – that’s where the hollow points come in.


(2) The deeper the projectile penetrates the quarry the longer the HOLE. And again, more crushed tissue is better than less.

And:
(3) A HOLE with two blood drains (entrance and exit wound) bleeds better than a hole with only one drain. More blood loss in less time kills quicker.
➔ Therefore, with all other things equal, a higher velocity is better. (Typical AG quarry are so small that too little penetration is rarely a problem.)


(4) The larger the meplat – the flat surface of the projectile – the more tissue will actually be crushed when making the HOLE.
(4a) ➔ Therefore:
• Flat points or wadcutters with their very large meplat and sharp edge crush the most tissue (80-90%+ of the projectile’s diameter).

• Second are unexpanded hollow points, with some having meplats as large as wadcutters, though some others have much smaller meplats (the hollow point cup is part of the meplat).

• Last are domed and pointed projectiles that crush only 65-70% of the tissue [figures adapted from Schaefer, 2014-2018, from PB]. Domed and pointed projectiles have a tendency to push the tissue aside instead of crushing it. They cut through flesh much like a welldriller – with ease the drill goes in deep. Clearly, a bulldozer-nose is better than a welldriller-nose. Domed pellets have a higher BC when passing through air, and have therefore also a higher “tissue BC” (as Bob Sterne [GTA: rsterne] describes this).

(4b) ➔ Additionally, hollow points that expand their overall diameter upon impact will crush more tissue (usually, they also expand their meplat). For example, a .22 cal projectile that expands to .295 increases its impact area by 85%, resulting in 85% more tissue crushed! (in metric measurements: A 5.5mm projectile that expands by only 2mm to 7.5mm causes 85% more crushed tissue.)
Note that for a substantial HP expansion the impact velocity must be fairly high, usually at least 700 to 800fps.

(4c) ➔ Sometimes a hollow point projectile will not expand beyond its original diameter. Nevertheless, often its hollow point cup does expand – thus enlarging the meplat. This results in more tissue being crushed.
In many cases hollow points fly with a much better BC than either a wadcutter or a pellet with a larger caliber (and with the same weight) – but upon impact they expand and crush as much tissue as the wadcutter or as the larger caliber pellet: that is the best of both worlds...!


(5) Some projectiles fragment inside the quarry. The HP pellets with ballistic tip usually shed the tip, some pellets leave their expanded head behind and only base with the skirt continues forward (e.g., RWS Super-H-Point), and some projectiles simply come to pieces at very high impact velocities. Sometimes these fragments could create their own wound cavities and increase tissue damage, though at the low AG velocities this is less likely.


(6) Exception for the above principles of a better HOLE:
For some quarry and certain shots we need to make the HOLE into a tough skull before the projectile can do damage to the brain.
➔ Therefore, to break through hard bone the best projectile will have a high impact velocity to actually break through (= the threshold velocity). It will be made from harder lead (lead with a high antimony content, e.g. H&N pellets). It will be domed or pointed rather than a projectile with a large meplat (the flat area that wadcutters and many hollow point pellets have). And it will have a higher sectional density (i.e., heavier if the diameter [caliber] remains the same, or – if the caliber can be varied, rather thin and long, than thick and short).






This thread is PART (1) of a four-part series, here in logical order and with links to each:

● PART (1) Quarry: What kills’em dead – the Mechanics of Killing
[The current thread.]


● PART (2) How Much Hollow Point Expansion Does How Much More Damage?
• A larger projectile makes a larger HOLE.
• So, how much larger is the HOLE if I go from .177 cal to .25 cal? (results in Table 1)
• And how much larger is the HOLE if my hollow point projectile expands 1/10 of an inch? Or 1mm? (results in Table 2)
http://www.airgunbbs.com/showthread....mage&p=7977495


● PART (3) Hollow Point Pellets – Comparison of Specs & Performance
The attached HP Pellet Specs & Performance Chart (.22cal) answers some of the following questions:
• Which HP projectiles expand better to make a Better HOLE in the quarry? –– The faster, softer HP projectiles with larger, deeper HP cups, and expansion aids do!
• What HP pellets are out there? And how do they compare (specs!)?
• How far could I shoot a certain HP pellet and still expect expansion (given the power of my gun)?
• Some HP are really long and might not fit into my magazine...: How long are the long ones really?
http://www.airgunbbs.com/showthread....ison&p=7977496


● PART (4) Hollow Points – Testing How Much They Expand and How Far They Penetrate
Every hollow point projectile (pellet or slug) performs differently, in line with its specs and the conditions. Find a collection of Projectile Expansion and Penetration Test results for both HP pellets and slugs.

(4a) HP Pellet Projectile Expansion and Penetration Tests
http://www.airgunbbs.com/showthread....tion&p=7977497
(4b) HP Slug Projectile Expansion and Penetration Tests
http://www.airgunbbs.com/showthread....rate&p=7900113


I hope this will be helpful to some!


Matthias



*Sources:
Matt. (2019). Terminal ballistics: How bullets wound and kill. Retrieved from the Everyday Marksman website, at
https://www.everydaymarksman.co/mark...al-ballistics/

Fackler, Martin L. (1988). Effects of small arms on the human body. Research Report. Letterman Army Institute of Research, Division of Military Trauma Research. Retrieved from
https://web.archive.org/web/20120218...small_arms.pdf

Arborelius, Ulf P. (1999-2013). Shooting holes in wounding theories: The mechanics of terminal ballistics. Retrieved from
http://www.rathcoombe.net/sci-tech/b.../wounding.html

Newgard, Ken. (1992). The physiological effects of handgun bullets: The mechanisms of wounding and incapacitation. Wound Ballistics Review, 1(3): 12-17.
https://drive.google.com/drive/folde...3pWYVVJeGlGaFE

Hollerman, J. J., Fackler, M. L., Coldwell, D. M., & Ben-Menachem, Y. (1990). Gunshot wounds: 1. Bullets, ballistics, and mechanisms of injury. American Journal of Roentgenology, 155(4), 685-690.
https://www.ajronline.org/doi/abs/10....155.4.2119095

Schaefer, John C. (2014-2018). Terminal ballistics. Retrieved from
http://www.frfrogspad.com/terminal.htm
and http://www.frfrogspad.com/terminal2.htm

Gateway to Airguns. (Ed.). (2018). Hunter’s terminal ballistics. [Thread]. Retrieved from
https://www.gatewaytoairguns.org/GTA...p?topic=148277

● Some of Bob’s excellent articles on airgun terminal ballistics (some are about slugs but the principles are similar for pellets):
Sterne, Bob [rsterne]. (2020, Apr. 15). The effect of caliber on airgun pellet performance. HardAir Magazine. Retrieved from
https://hardairmagazine.com/ham-colu...t-performance/

Sterne, Bob [rsterne]. (2020, Jun. 22). Bob Sterne discusses hollowpoint slug design. HardAir Magazine. Retrieved from
https://hardairmagazine.com/ham-colu...t-slug-design/

Sterne, Bob [rsterne]. (2020, Mar. 17). Airgun pellet penetration – the real story. HardAir Magazine. Retrieved from
https://hardairmagazine.com/ham-columns/airgun-pellet-penetration-the-real-story/