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DeltaKilo
02-25-2011, 08:53 PM
The Presumptive Hazards of Over-Penetration
Failures to stop a suspect because of under-penetration, poor bullet placement, and completely missing the target are far more significant problems than over-penetration. With shots to the center of mass, if a handgun or rifle bullet fails to have enough penetration to reach the large blood bearing vessels and organs in the torso, rapid physiological incapacitation is unlikely and an opponent may remain a lethal threat to officers and citizen bystanders. Conversely, if a bullet fired by officers completely penetrates a violent criminal and exits downrange, the bullet will certainly have had enough penetration to reach the large blood bearing vessels or organs in the torso. As a result, it is more likely to have caused sufficient hemorrhage to induce hypovolemic shock--the only reliable method of physiological incapacitation in the absence of CNS trauma.

Unfortunately, according to the available published date, the majority of shots fired in the field by U.S. LE officers miss their intended target. According to published NYPD SOP-9 data, the NYPD hit ratio by officers against perpetrators in 2000 was 12.3% of shots fired and in 2001 13.5% of shots fired. The Miami Metro-Dade County PD had hit ratios ranging between 15.4% and 30% from 1988-1994. Portland PD reported hits with 43% of shots fired at adversaries from 1984-1992, while Baltimore PD reported a 49% average hit ratio from 1989-2002.

Given that the reported averages for LE officers actually hitting the suspect ranges between 12% to 49% of shots fired, more concern should be given to the between 51-88% of shots fired by LE officers which completely MISS the intended target and immediately result in a significant threat to any person down range, rather than excessively worry about the relatively rare instance where one of the 12%-49% of shots fired actually hits the intended target and then exits the perpetrator in a fashion which still poses a hazard.

In short, the consequences of projectile under-penetration are far more likely to get officers and citizens killed than over-penetration issues.

Tamara
02-26-2011, 05:56 PM
I've never understood the bizarre idea that people are going to run and line up to stand behind someone who's being shot at...

jslaker
02-26-2011, 06:25 PM
There's an important corollary to this given the rising popularity of pocket pistols -- JHP doesn't always mean better.

The overwhelming majority of JHP loads you're going to come across in low-energy calibers like .380 ACP are going to tend to significantly underpenetrate; 7-9" is pretty typical if the round expands. There are a handful of loadings that can just barely hit the 12" standard, but most of the testing I've seen there has generally been from guns with longer barrels than the 2.75" barrel you're going to find in something like a Ruger LCP. You have to be incredibly selective in your load choice either way.

Personally, I'm inclined to stick with FMJs for anything lower energy than 9x19 as a result. I want placement, penetration, then expansion, in that order.

DeltaKilo
02-26-2011, 07:19 PM
There's an important corollary to this given the rising popularity of pocket pistols -- JHP doesn't always mean better.

The overwhelming majority of JHP loads you're going to come across in low-energy calibers like .380 ACP are going to tend to significantly underpenetrate; 7-9" is pretty typical if the round expands. There are a handful of loadings that can just barely hit the 12" standard, but most of the testing I've seen there has generally been from guns with longer barrels than the 2.75" barrel you're going to find in something like a Ruger LCP. You have to be incredibly selective in your load choice either way.

Personally, I'm inclined to stick with FMJs for anything lower energy than 9x19 as a result. I want placement, penetration, then expansion, in that order.

Absolutely. With sub-calibers like .380 and lower, FMJ is the better choice just to make it to the minimum penetration depth necessary to make a dent.

I also typically will suggest a good little revolver instead of any sub-caliber semi-auto.

DeltaKilo
02-26-2011, 07:21 PM
I've never understood the bizarre idea that people are going to run and line up to stand behind someone who's being shot at...

I think the common thought and issue is if one is addressing a threat in an area such as a Mall or other crowded place where you may not have a clear shooting lane beyond the initial target. In these cases, or crowded streets, or similar, the concern for overpenetration, while possibly overthought, is most certainly valid.

Tamara
02-26-2011, 08:01 PM
I was being sardonic, of course.

But still, even in the hypothetical food court scenario, if even as little as a third of your shots are going to go wild, concerns about overpenetration are just so much picking fly poop out of pepper...

MTechnik
02-26-2011, 08:06 PM
I was being sardonic, of course.

But still, even in the hypothetical food court scenario, if even as little as a third of your shots are going to go wild, concerns about overpenetration are just so much picking fly poop out of pepper...

This is where I feel barrier penetration and dwelling setting are important.

If you do miss in your home, how many layers of drywall and other homes are you going to go through?

ToddG
02-26-2011, 08:50 PM
Just to follow on to what Tam and MTechnik said...

I don't think much about overpenetration. (insert your own joke) Because I'm always cognizant of the possibility of a miss -- especially when things are dynamic and one or more parties involved may be moving -- my concern is much more about what's downrange.

Don't worry about whether the bullet will go through the guy's chest, out his spine, and hit the nun standing behind him. Worry that the guy might zig when you thought he was going to zag, and you accidentally shoot the nun dead.

David B.
02-26-2011, 11:40 PM
I took a defensive pistol class back when I was living in Bakersfield, and one of the drills the instructor ran was to setup a target with a few no shoots behind it.

The student was unaware of the target array until the lights were turned on (which was the go signal) and we hand to move to adjust our shooting angle so that the no shoots were not directly beyond the target, in th line of fire, in case we had a miss or I guess over penetration.

It was an interesting drill that got me thinking about the angle I engaged a target in relation to the people around.

In most instances a simple sidestep of a few feet was enough to change the angle so that bystanders (at least in their static position) were not in the direct line of fire.

Know your target and what is beyond.

God Bless,
David

MikeO
05-05-2011, 12:57 PM
The last two years (95/96) NYPD issed FMJ ammo, 41 of the 121 people (34%!?) hit by NYPD bullets were hit by NYPD bullets that went through somebody else first.

Who lines up to get hit? Apparently 18 suspects and 23 bystanders/cops did those two years... ;)

Meanwhile, the local PD (1100 officers) has gone 20+ years w/o doing what NYPD (38,000 officers) did 41 times those two years... ;)

rsa-otc
05-05-2011, 03:04 PM
My take for what it's worth:

My carry ammo MUST penetrate sufficiently to reach the vitals of my assailant and be effective.

The danger of the more likely 45-85+ percent (depending on whose stats you use) misses are an issue that must be given consideration and addressed to reduce the likely hood of unintended injuries. (this is not a criticism of the membership here, I don't think the members of this forum or some of the other more responsible forums feel otherwise, in fact we are doing our best to address this in ourselves and our students)

BUT it is also dangerous liability wise to minimize the danger of over penetration based on our statistical likely hood of missing the intended target, especially on a public forum. I'm pretty sure this logic will not fly with John Q jury person and they will not look kindly at such comments. They expect us to hit what we're shooting at. Lets face it, if we hit an unintended target we're paying for it. The amount paid can & will be based on our actions and comments leading up to, during and after the shooting.

I want a round that if I do my part it will do it's part with a minimal possibility of passing thru the assailant with enough energy to endanger innocents. :)

MikeO
05-06-2011, 11:08 AM
My take for what it's worth:

My carry ammo MUST penetrate sufficiently to reach the vitals of my assailant and be effective.

I want a round that if I do my part it will do it's part with a minimal possibility of passing thru the assailant with enough energy to endanger innocents. :)

We seemed to have determined the 9 minimeter Silvertip is too little, and FMJ is too much, so how much is enough?

The FBI's sweet spot of 12 - 18 inches sounds good to me, and NYPD's current duty round (Speer 124 +P GD IIRC) fits, as do many others.

Depending on your software, your hardware could do more w less, or less w more. :)

CAW
05-19-2011, 01:41 PM
I think the most important job for a bullet to do is penetrate far enough to go through(preferably straight through without change of course) the vitals. Nothing less, maybe more… I'm not going to consider carrying anything less. If i need the tool for the job, I need the tool for the job.

I won't carry HP's in .380. I don't load birdshot in shotguns unless I am hunting birds or paper. You also won't see me shooting up the neighborhood with an AK-47 ;)

WDW
05-27-2011, 07:37 PM
Just to follow on to what Tam and MTechnik said...

I don't think much about overpenetration. (that's what she said) Because I'm always cognizant of the possibility of a miss -- especially when things are dynamic and one or more parties involved may be moving -- my concern is much more about what's downrange.

Don't worry about whether the bullet will go through the guy's chest, out his spine, and hit the nun standing behind him. Worry that the guy might zig when you thought he was going to zag, and you accidentally shoot the nun dead.