🔴Hollow Point Pellets — Testing How Much They Expand and How Far They Penetrate

Hollow Point Pellets — Testing How Much They Expand and How Far They Penetrate
 
This thread is PART (4a) of a four-part series. The other threads explain the mechanics of killing, which projectiles kill better, and which HP pellets are available (detailed specs of .22cal @ US). Links to the other parts you’ll find below.
Over the past months I have collected and summarized the results of a number of Projectile Tests (PT) that I will post on this thread, and I’ll continue to post new ones as I find them.
 
When sifting through the projectile tests on forums and Youtube I decided to mostly leave out play-dough, clay, and water as ballistic mediums. They are much harder than animal tissue and therefore will exaggerate HP expansion greatly!
Reading what terminal ballistician have written, I mostly considered calibrated ballistic gel 10% (some 20%), ClearBallistics.com gel, home-made ballistic gelatin (“DIY”), glycerin soap (melt-and-pour), wet newsprint, and of course… – real quarry (dead or alive)! 

 
Test Protocols
 The testers most often do not give the specific details of their test protocol (impact velocity, type of ballistic gel), so we are left to reconstruct those. Similarly, many testers do not give specific details of their test results – which requires reconstructing them. I used the ChairGun ballistic calculator, the BC values from my Pellet BC Table and my Slug Table, and I measured proportions in the photos/videos to arrive at the data as presented in the Projectile Tests (PT).
 
HP Expansion Data
 The purpose of a hollow point projectile is the expand and increase in diameter when it hits the quarry. The larger its diameter – the larger the impact area – the larger the permanent wound cavity (the HOLE) – the larger the amount of flesh being crushed – the larger the chance that the wound cavity includes heart/lungs, brain/spine, and/or a larger amount of blood vessels to cause hemorrhaging.
 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.)
 
Meplat Expansion Data
 The larger the flat part of the projectile’s nose – the meplat – the more tissue will actually be crushed when making the HOLE. The hollow point cup is also part of the meplat. At lower impact velocities a HP might not expand much in its diameter, but it might expand its HP cup – its meplat – and thus crush more tissue.
 
Penetration Data
 The animals that are appropriate to hunt with airguns are typically small. Therefore a hunter usually does not worry if the projectile will penetrate far enough, as shots often penetrate so far that they will simply exit the quarry (assuming typical calibers of .177, .22, and .25, and typical muzzle energies of 12, 20 to 30, and 40FPE). Penetration becomes an issue on head shots of larger animals as the skull is usually difficult to penetrate. The tests presented here, however, use a soft ballistic mediums to simulate flesh rather than skull bone. For skull penetration tests different ballistic mediums are necessary. However, the penetration numbers will indicate which projectile/velocity combinations are especially effective at applying their kinetic energy to the quarry instead of passing through it like an icepick. This is to show that as the diameter of the projectile increases its penetration decreases.
 
All the PT include the following data:
 • Test designator, PTXXX (where XXX is a counter; PT = projectile test)
 • Ballistic medium
 • Projectiles (brand, model, weight)
 • Impact velocity, and impact energy
 • Meplat (expanded flat part of the nose – the larger the more crushed tissue)
 • Expansion (total diameter)
 • Penetration
 • Notes (ballistic tip behavior, shotline, etc.)
 • Source (and notes)
Measurements in imperial and metric.
 Red writing indicates details that likely skewed the test results to be too optimistic (e.g., a harder then flesh ballistic medium).
 
I thank all the airgunners who have run these sometimes very time-consuming tests, and for putting them out there for us so we could learn from them. THANK YOU!! 😊👍🏼
 
 
 
 
🔺This thread is PART (4a) of a four-part series. Here’s an overview with links to the other parts:
 
● PART (1) Quarry: What kills’em dead – the Mechanics of Killing
• What kills is a Permanent HOLE in the quarry – nothing else. Only crushed tissue kills, not “energy dumped,” nor a “temporary wound cavity,” nor “hydrostatic shock.”
 • For the HOLE to kill – it must be in the right place in the quarry: brain/spine or heart/lungs or arteries/veins (to cause hemorrhaging).
 • The projectiles that make a Better HOLE in the quarry are –– larger, faster, bulldozer-nose, expanding projectiles.
https://www.gatewaytoairguns.org/GTA/index.php?topic=182421


● 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)
https://www.gatewaytoairguns.org/GTA/index.php?topic=182422
 
● 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?
https://www.gatewaytoairguns.org/GTA/index.php?topic=182425


● 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
https://www.gatewaytoairguns.org/GTA/index.php?topic=182427

(4b) HP Slug Projectile Expansion and Penetration Tests
https://www.gatewaytoairguns.org/GTA/index.php?topic=175823

 
I hope this will be helpful to some!

Matthias

PT004

BY:  Hajimoto

PT011 

BY:  Bob Sterne

PT009

PT022

4 More Projectile Expansion and Penetrations Tests:   

PT025

PT016

Pellet Test  PT070

PT011

By Bob Sterne