chriseckhardt/ballistics by ernunnos

## ballistics by ernunnos
Wound ballistics part III.
Weirdly, the ammunition world seems a lot like the musical world. Nothing has really changed since about 1995. We're just remixing the old styles and putting it in prettier boxes. If you read gun magazines and discussion groups, you'd think no new work on the subject of how bodies respond to getting shot had been for the last 20 years or so.
And that's simply not true.
There's a couple of geeks out there by the name of Courtney & Courtney (married PhDs) who've been publishing a bunch of papers on brain injury produced by "ballistic presure waves", which could be caused by bullets or even just blunt force trauma to the body, like getting hit by a truck or an explosive blast wave. These are directly related to energy (ft-lbs) and inversely related to penetration. (Less is better, to a point.)
I'm linking the page that leads to a bunch of their papers below, but here's the salient points of their model:
1. Animal testing shows that if you can produce 30 PSI overpressure in the brain, you can knock 'em out cold. This seems reasonable. Fighter pilots "red out" from negative Gs that pull blood up into the brain.
2. If you can produce 750 PSI, 1" away from the bullet, it will be lower by the time the pressure wave reaches the brain. But that's still enough to produce a 50/50 chance of an instant "red out". If you can boost that to 1000 PSI, you increase brain pressure levels enough to improve chances of a "red out" to 75%.
3. Pressure, in turn, is proportional to energy/penetration distance. So you want to MAXIMIZE energy and MINIMIZE penetration, exactly the opposite of what we've been doing. They still say that penetration < 9.5" reduces effectiveness, and you can't just shoot them in the toe and expect a stop, because the bullet's got to apply that pressure to the blood stream in a big way. So center of mass hits are still important. You want that temporary cavity to be shoving a big volume of blood around.
With a non-fragmenting bullet, and 12" of penetration, you need 500 ft. lbs to produce 750 PSI. By reducing the penetration to 10" ("It's not the fall that kills you, it's the sudden stop at the end"), you can make nearly 1000 PSI with 500 ft-lbs of energy. Using fragmenting bullets - which may have parts that penetrate to the final depth, but stop other parts much shorter - you can get over 1000 PSI (75% instant stop chance) with as little as 350 ft-lbs.
.357 SIG can produce 500-550 ft-lbs all day, every day. Penetration depth depends on the bullet. .357 Magnum can do the same... or over 700 ft-lbs with hot loads. If you're using a hollow point that stops in a reasonable distance, you're talking over 1000 PSI with standard, non-fragmenting rounds, and - if this model is correct - an 80% chance of instant incapacitation from a single shot even without a lucky/skilled central nervous system hit!
So, here's what appeals to me about this: Fackler was largely right. For standard .380, .38 Special, 9mm, and even .45 ACP - anything under 300-350 ft-lbs - using standard, non-fragmenting bullets, you're only going to see pressure effects 10-15% of the time. Not enough to rely on.
But...
If you can handle some more recoil, use a 9mm +P+, a .38 Super, a .357 SIG, or .357 Magnum, something that makes 450-700 ft-lbs, and ammunition with a bullet that doesn't conform to Fackler's deeper-is-better standard and stops in no more than 12", rather than 12" minimum... you can expect 50-75% of your shots to instantaneous redouts. Which will look, on video, like the famous "DRT". They're not really dead, at least not right away. They just fainted from brain overpressure, and then have a chance to do the "slow" bleed out.
Is this the final word? Probably not. You can always do more research. But most people - even gun people - aren't even aware that this research exists. Yet it explains the massive difference in performance between .38 and .357, and the surprisingly good performance of the old (introduced 1985) Federal 9BPLE +P+, which doesn't meet Fackler's standards, but produces 465 ft-lbs and stops in 11 inches. Which by Courtney & Courtney's model means 750 PSI and a 50% chance of instant stop. If you can put two in the boiler, that's only a 1/4 chance that they won't drop from at least one of the bullets, and that's not including the usual factors of CNS hits and blood loss.
So what do I carry these days? 9BPLE or any .357 SIG. In .45 ACP, Hornady 185 gr. +P Critical Defense, which makes over 500 ft lbs and stops faster than other brands.
	Wound ballistics part III.
	Weirdly, the ammunition world seems a lot like the musical world. Nothing has really changed since about 1995. We're just remixing the old styles and putting it in prettier boxes. If you read gun magazines and discussion groups, you'd think no new work on the subject of how bodies respond to getting shot had been for the last 20 years or so.
	And that's simply not true.
	There's a couple of geeks out there by the name of Courtney & Courtney (married PhDs) who've been publishing a bunch of papers on brain injury produced by "ballistic presure waves", which could be caused by bullets or even just blunt force trauma to the body, like getting hit by a truck or an explosive blast wave. These are directly related to energy (ft-lbs) and inversely related to penetration. (Less is better, to a point.)
	I'm linking the page that leads to a bunch of their papers below, but here's the salient points of their model:
	1. Animal testing shows that if you can produce 30 PSI overpressure in the brain, you can knock 'em out cold. This seems reasonable. Fighter pilots "red out" from negative Gs that pull blood up into the brain.
	2. If you can produce 750 PSI, 1" away from the bullet, it will be lower by the time the pressure wave reaches the brain. But that's still enough to produce a 50/50 chance of an instant "red out". If you can boost that to 1000 PSI, you increase brain pressure levels enough to improve chances of a "red out" to 75%.
	3. Pressure, in turn, is proportional to energy/penetration distance. So you want to MAXIMIZE energy and MINIMIZE penetration, exactly the opposite of what we've been doing. They still say that penetration < 9.5" reduces effectiveness, and you can't just shoot them in the toe and expect a stop, because the bullet's got to apply that pressure to the blood stream in a big way. So center of mass hits are still important. You want that temporary cavity to be shoving a big volume of blood around.
	With a non-fragmenting bullet, and 12" of penetration, you need 500 ft. lbs to produce 750 PSI. By reducing the penetration to 10" ("It's not the fall that kills you, it's the sudden stop at the end"), you can make nearly 1000 PSI with 500 ft-lbs of energy. Using fragmenting bullets - which may have parts that penetrate to the final depth, but stop other parts much shorter - you can get over 1000 PSI (75% instant stop chance) with as little as 350 ft-lbs.
	.357 SIG can produce 500-550 ft-lbs all day, every day. Penetration depth depends on the bullet. .357 Magnum can do the same... or over 700 ft-lbs with hot loads. If you're using a hollow point that stops in a reasonable distance, you're talking over 1000 PSI with standard, non-fragmenting rounds, and - if this model is correct - an 80% chance of instant incapacitation from a single shot even without a lucky/skilled central nervous system hit!
	So, here's what appeals to me about this: Fackler was largely right. For standard .380, .38 Special, 9mm, and even .45 ACP - anything under 300-350 ft-lbs - using standard, non-fragmenting bullets, you're only going to see pressure effects 10-15% of the time. Not enough to rely on.
	But...
	If you can handle some more recoil, use a 9mm +P+, a .38 Super, a .357 SIG, or .357 Magnum, something that makes 450-700 ft-lbs, and ammunition with a bullet that doesn't conform to Fackler's deeper-is-better standard and stops in no more than 12", rather than 12" minimum... you can expect 50-75% of your shots to instantaneous redouts. Which will look, on video, like the famous "DRT". They're not really dead, at least not right away. They just fainted from brain overpressure, and then have a chance to do the "slow" bleed out.
	Is this the final word? Probably not. You can always do more research. But most people - even gun people - aren't even aware that this research exists. Yet it explains the massive difference in performance between .38 and .357, and the surprisingly good performance of the old (introduced 1985) Federal 9BPLE +P+, which doesn't meet Fackler's standards, but produces 465 ft-lbs and stops in 11 inches. Which by Courtney & Courtney's model means 750 PSI and a 50% chance of instant stop. If you can put two in the boiler, that's only a 1/4 chance that they won't drop from at least one of the bullets, and that's not including the usual factors of CNS hits and blood loss.
	So what do I carry these days? 9BPLE or any .357 SIG. In .45 ACP, Hornady 185 gr. +P Critical Defense, which makes over 500 ft lbs and stops faster than other brands.