GTA
All Springer/NP/PCP Air Gun Discussion General => Hunting Gate => Topic started by: JungleShooter on January 10, 2021, 04:39:41 PM
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How Much Hollow Point Expansion Does How Much More Damage?
The point of a hollow point projectile is to expand and make a bigger HOLE – therefore crushing more tissue in its path.
So, how much bigger is the HOLE if I go from .177 cal to .25 cal? Or from .22 cal to .30 cal? See the answers in the attached Table 1 below.
How much bigger is the HOLE if my hollow point projectile expands 1/10 of an inch? Or 1mm? The answers are in Table 2 (attached below).
🔺 Note that this thread is PART (2) 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
• 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 (https://www.gatewaytoairguns.org/GTA/index.php?topic=182421)
● PART (2) How Much Hollow Point Expansion Does How Much More Damage?
[The current thread.]
● 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 (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 (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 (https://www.gatewaytoairguns.org/GTA/index.php?topic=175823)
I hope this will be helpful to some!
Matthias
🔺 Attachments
Wound Cavity and Caliber. 047.pdf
Wound Cavity Expansion with HP. 047.pdf
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Your points are valid but you are leaving out penetration. We need a big enough hole but we also need a deep enough hole to get to vital tissue. Admittedly this is only an issue at the lower end but it can be an issue. The first squirrel I shot at this house was with a 1377 with about 5 fpe. The pellet stopped after breaking the near side front shoulder. So the squirrel died slowly due to insufficient penetration. A bigger hole would have had the same effect. Once we get to the vitals, how big the hole is matters. But we have to get there.
When we start adding the variable of expansion, we again need more velocity in our projectiles. We are going to penetrate less if our projectile expands. I tested the 22 pellets I had on hand in wet phone books to see how much penetration I got. There are some that think wet newsprint gives results similar to muscle tissue. My little 1377 only went about 1.5 inches using a gamo redfire that did not expand. The only 22 pellet that expanded was a metal mag weighing about 18 grains. It penetrated about the same as 14.3 grain Crosman domed and hollow point pellets. The deepest penetrator was a 21.3 grain Baracuda. I later shot a dead squirrel hanging by it's tail to see how a couple of these pellets penetrated the body cavity. Both the 14.66 grain H&N and the 21.3 grain Barracuda, both domed, went through the squirrel but the skirt caught in the skin on the far side. Definitely far enough to hit something vital but a shot all the way through would bleed more.
In powder burners there is a lot of debate about penetration versus expansion. Some people use highly fragile varmit bullets on deer. A hit in the lungs will put the deer down quickly but if you miss and hit the shoulder you only injure the deer. So most use controlled expansion bullets to get some expansion to increase the permanent cavity. With the higher velocity the temporary cavity may also destroy tissue and expansion can help with that.
I believe the criteria is to get sufficient penetration first and foremost. In the less powerful airguns this means you do not want expansion of the projectile. But if you have sufficient power to have both, bigger deep holes will kill faster. But shallow wide holes work worse than narrow deep ones.
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The penetration aspect will all depend on what you're shooting though. A 7.1 grain hp will penetrate all the way through a red squirrels head, a 8.64 dome will penetrate all the way through on a body shot on a starling. That extra penetration is just energy that gets wasted on whatever is behind your target. I'll use whatever is most accurate in my gun, but prefer something that expands if possible. However If I were trying to penetrate the skull of a raccoon I'd want something with greater penetration. So it all depends on what you're throwing that pellet at. This series of posts he's putting out here gives you an overview and then you can use that info to choose the right pellet depending on what you are hunting.
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With air guns, I've always valued accuracy first. I never really gotten the best accuracy out of any of the hollow point designs.