FBI to 9mm

[mavracer]

In past decades, there was an advantage (IMHO) to carrying a 40 or 45 over the 9mm. But I don't believe that to be true anymore.

I keep hearing this mantra repeated, why do you think it isn't? The 40 and 45 still have the same advantage of ~20% more momentum which in soft tissue leads to ~20% larger permanent cavity. The odds that the 20% is going to make a difference hasn't changed either.
I've said it before they're all a compromise and "best compromise" is an oxymoron

 

[TimSr]

How in the world would whether someone is enforcing a law pertaining to a Federal crime or one that pertains to a state crime have any bearing on the subject at all?

Civilians are not called to break up fight in bars, to intervene in domestic violence cases, or to make traffic stops.

Substitute FBI for "civilians" and you've answered your own question.

From that standpoint, FBI use of force engagements more closely resemble those of civilians than those of uniformed officers.

Really? Civilans are called to arrest counterfeiters, solve kidnappings, find interstate serial killers, mail fraud, investigate "hate crimes" and terror cells?

Seriously, you think that the people the FBI encounter in the course of their duties more closely ressemble the bad actors we might encounter in our life than our local police and sheriff?

 

[OldMarksman]

Posted by maracer:

The 40 and 45 still have the same advantage of ~20% more momentum which in soft tissue leads to ~20% larger permanent cavity.

Do you have a demonstrated basis for asserting the size of the permanent cavity is directly proportional to momentum, all other things being equal?

The odds that the 20% is going to make a difference hasn't changed either.

What are those odds, and how do they relate to the odds that additional hits will "make a difference"?

Rob Pincus on the subject:

The damage that is done is created through cutting and crushing. The difference of a few grains of weight, a few feet per second of speed or a millimeter (literally) of diameter are not worth giving up on the faster strings of fire or the higher capacity mentioned above. While the .40 S&W round, especially in heavier versions, has more potential for penetration of intermediate barriers, the data on actual personal defense shooting suggests overwhelmingly that there are not likely to be any hard barriers to be penetrated.

Physics dictates that the 9mm is going to be a more manageable round (lower recoil) than the .40 S&W out of any particular firearm. So, no matter how much you train and how much you practice, everyone should be able to shoot a string of Combat Accurate 9mm rounds faster than they can fire a string of .40.


It is important to note that I am not arguing that a single .40S&W bullet doesn’t hold more potential to stop in any event, rather I believe that the small increase in potential is not worth the absolute known detriments in recoil and capacity.

As I discussed in point number one, for all shooters, at some point, there will be a moment when they can fire one more round of 9mm in any given period of time. That extra round’s capacity to wound will far outweigh the miniscule difference in potential for any individual bullets.

http://www.imakenews.com/valhalla/e_article002168437.cfm?x=bk1b43S,bbSbHJ7K

 

[OldMarksman]

Posted by TimSr:

How in the world would whether someone is enforcing a law pertaining to a Federal crime or one that pertains to a state crime have any bearing on the subject at all?

Civilians are not called to break up fight in bars, to intervene in domestic violence cases, or to make traffic stops.

Substitute FBI for "civilians" and you've answered your own question.

And my question was rhetorical, intended to point out the similarity between civilian encounters and those of FBI agents, and the differences between those and the encounters of uniformed police officers.

From that standpoint, FBI use of force engagements more closely resemble those of civilians than those of uniformed officers.

Really? Civilans are called to arrest counterfeiters, solve kidnappings, find interstate serial killers, mail fraud, investigate "hate crimes" and terror cells?

Certainly civilians do not do those things for a living; they do other things. But that is not the point. The point is, that since neither civilians nor FBI agents are called upon to break up fight in bars, to intervene in domestic violence cases, or to make traffic stops, their use of force engagements, which are defensive in nature and which do not have to do with enforcement of the law in circumstances that start out violently, are likely to be much more similar to those of FBI agents than to those of unformed sworn officers.

As a I recall, Tom Givens provides some useful discussion of that point, and an example or two.

Seriously, you think that the people the FBI encounter in the course of their duties more closely ressemble the bad actors we might encounter in our life than our local police and sheriff?

In terms of height, weight, age, and condition, I see no reason for any overall difference in resemblance.

But if there is any, I fail to see how it might have anything to do with the weapons performance parameters tested and recommended for law enforcement by the FBI.

And perhaps you missed that last point: the recommendation from the FBI training division at Quantico was intended for law enforcement agencies and law enforcement officers.

 

[Catfishman]

I keep hearing that ammo technology has improved so much that 9 mm ammo is as good as 40 Cal and 45 ammo.
That begs the question, didn't 45 ammo and 40 cal also improve?
And isn't all handgun ammo underpowered? So if we have a technological improvement shouldn't we go to 45 ACP or 10 mm and not back to 9 mm?

 

[4V50 Gary]

Was told that the FBI still has hundreds of thousands of rounds of 10mm left over from the olde days.

 

[OldMarksman]

Posted by Catfishman:

I keep hearing that ammo technology has improved so much that 9 mm ammo is as good as 40 Cal and 45 ammo.
That begs the question, didn't 45 ammo and 40 cal also improve?

Probably.

And isn't all handgun ammo underpowered?

Yes.

So if we have a technological improvement shouldn't we go to 45 ACP or 10 mm and not back to 9 mm?

No.

For self defense against human beings, the requirement is to hit and damage certain unseen critical body parts within a fast moving body very quickly. Requirements are (1) penetration and (2) striking those rather small parts. The second is largely a matter of chance, and that chance is increased markedly as the number and rapidity of controlled shots increases.

That can be enhanced by relatively low recoil; more capacity helps too.

 

[TimSr]

In terms of height, weight, age, and condition, I see no reason for any overall difference in resemblance.

But if there is any, I fail to see how it might have anything to do with the weapons performance parameters tested and recommended for law enforcement by the FBI.

How about more common and typical crimes of the area, seasonal apparel, culture, weapons, tactics, MO?

And perhaps you missed that last point: the recommendation from the FBI training division at Quantico was intended for law enforcement agencies and law enforcement officers.

This was my main point that you missed altogether. Why would state and local law enforcement defer to the agency with least experience that may or may not be even be relevant to local challenges, and use them for recommendations on weapons and training?

I've never met an FBI agent, spoke to one on the phone once in my life, and I've never even heard of a recent FBI shootout. Maybe that's why they have to keep talking a bout a shootout 30 years ago. Meanwhile, I get to hear about NE Ohio police shootouts weekly.

Honestly, I have little interest in what the FBI is using, or was using in 1987, and am much more interested in what Cleveland, Akron, and Columbus police were using last week, and how well it performed against the types of threats we commonly deal with here.

 

[mavracer]

Do you have a demonstrated basis for asserting the size of the permanent cavity is directly proportional to momentum, all other things being equal?

It's really simple physics, when you define the permanent cavity as what is directly in the path of the bullet you're eliminating all the effects that energy has from the discussion.

What are those odds, and how do they relate to the odds that additional hits will "make a difference"?

What are the odds you'll have time for additional hits?

For self defense against human beings, the requirement is to hit and damage certain unseen critical body parts within a fast moving body very quickly. Requirements are (1) penetration and (2) striking those rather small parts. The second is largely a matter of chance, and that chance is increased markedly as the number and rapidity of controlled shots increases.

By that logic why stop at 9mm? If the size of the hole doesn't matter 32ACP ball ammo will penatrate 12"+ and is even easier to control.

 

[OldMarksman]

Posted by mavracer:

It [asserting the size of the permanent cavity is directly proportional to momentum, all other things being equal] 's really simple physics, when you define the permanent cavity as what is directly in the path of the bullet you're eliminating all the effects that energy has from the discussion.

I don't think that's a very clear definition of permanent cavity at all, but we do not have to quibble about it. I think we all understand what it is.

But you did not anwser the question. The physics is not as simple as what many people believe it to be. If it were, and if we were talking about crushing and cutting material, we would be speaking of energy. Energy, or force times distance, is what we measure when we analyze compressing something, cutting something, bending something, crushing something, breaking something, bringing something to a complete stop in many media (e.g., automotive braking, converting kinetic energy to heat (or in some cases these days, to electrical energy). The change in kinetic energy is defined as work.

So, in terms of classic physics, one might tend to conclude that penetration is solely a function of energy rather than momentum, and one could readily demonstrate that penetration that results in a permanent hole in bone or armor or bricks is in fact a function of energy.

Quite obviously, it is also energy that causes the bending of parts of the bullet and the increase in diameter.

But when it comes to analyzing penetration in human bodies, it ain't quite that simple. That's because not all of the body is solid. To the extent that some of the body behaves more like an incompressible fluid, some of the forces on the bullet are in fact a function of momentum--just as in the case of a canoe paddle in water, or a helicopter rotor blade in air. In those situations, things relate to the changes in the velocity vectors and to the masses of the particles of the fluid.

So, penetration isn't all that simple, and for that reason, permanent capacity is even less so. As Rob Pincus points out, forensic examiners are often unable to determine, though the observation of the permanent would cavity, what it was that caused the wound.

What are the odds you'll have time for additional hits?

Higher if you can shoot more quickly and with control, of course, but if you do not have time,, and if your hits do not happen to damage anything critical, the size of the permanent cavity will not help.

By that logic why stop at 9mm? If the size of the hole doesn't matter 32ACP ball ammo will penatrate 12"+ and is even easier to control.

No one has said that it doesn't matter.

 

[OldMarksman]

Posted by TimSr:

How about more common and typical crimes of the area, seasonal apparel, culture, weapons, tactics, MO?

Seasonal apparel is addressed in the test protocols.

How might variations in culture, weapons, tactics, or MO enter into the wounding effectiveness of handguns?

Why would state and local law enforcement defer to the agency with least experience that may or may not be even be relevant to local challenges, and use them for recommendations on weapons and training?

One more time: the recommendation from the FBI training division at Quantico was intended for law enforcement agencies and law enforcement officers.

And one more time: had you read Handgun Wounding Effectiveness, you would understand that the FBI protocols are not based on "experience" in "real world gunfights".

Can you cite a better, more applicable, more complete, and better substantiated analysis, with more relevant test protocols?

Do you think that "local challenges" among law enforcement environments really vary that much?

Honestly, I have little interest in what the FBI is using, or was using in 1987, and am much more interested in what Cleveland, Akron, and Columbus police were using last week,....

What they were using last week was the result of decisions made some time before last week. Those decision were no doubt based on a number of factors, not all of them current today.

....and how well it performed against the types of threats we commonly deal with here.

Do you really believe for a moment that local deadly force encounter data are sufficient, considering how many variables are involved, to give any idea whatsoever about whether the handguns used are best for the purpose today ?

Do you really think that police boards in Cleveland, Akron, or Columbus would even consider using a few local anecdotal inputs to second guess the test-based recommendations of the FBI Training Division, FBI Academy, Quantico, VA?

 

[mavracer]

I don't think that's a very clear definition of permanent cavity at all, but we do not have to quibble about it.

Most everbody in the business agrees with my definition.

Quite obviously, it is also energy that causes the bending of parts of the bullet and the increase in diameter.

No it's not energy is the reason the bent part's not only have a hole in them but are in fact hotter. But I'm not getting into this argument again the proof is in the pudding or in this case jello.
40 S&W and 45 ACP leave a measurably larger permanent wound channel.

 

[JollyRoger]

Was told that the FBI still has hundreds of thousands of rounds of 10mm left over from the olde days.

The FBI still uses the 10mm in its sub gun, the HK MP5-10. It Is probably the largest single purchaser of 10mm in the country.

 

[OldMarksman]

Posted by mavracer:

Most everbody in the business agrees with my definition.

I have never seen anyone define the permanent cavity "as what is directly in the path of the bullet."

Col Fackler put it this way: "The main aim of a bullet is to crush, i.e., destroy the tissue actually hit by the bullet, and stretch which is the transient/radial displacement of adjacent tissues in the wake of the projectile. The wound path of the projectile is known as permanent cavity and the stretching is known as temporary cavity."

Now, this is beyond my knowledge base, but I have been told that a .38 LRN bullet will create a smaller permanent wound channel than will a .38 wadcutter or semi wadcutter bullet with the same diameter and the same penetration.

A JHP? Still larger.

No it's not energy [that causes the bending of parts of the bullet and the increase in diameter] is the reason the bent part's not only have a hole in them but are in fact hotter.

Of course it is energy that causes the bullet to expand! Of course JHP bullets have holes in them! And just where do you think that heat comes from?

40 S&W and 45 ACP leave a measurably larger permanent wound channel.

That would seem self evident, though again, it is reported that forensic pathologists often cannot distinguish among them after real shooting incidents.

The question is how important that is, and how that importance compares to that of additional hits.

 

[JollyRoger]

The FBI's decision to switch back to the 9mm was round-specific. Their ballistics testing unit routinely runs tests on ammunition based on some rigorous test requirements: the ammo has to perform consistently in calibrated ballistic gel under uniform conditions. In addition to the bare gel, t-shirt material and denim tests, the rounds are fired through plywood and auto windshield glass. In all cases, the bullet must go through the barriers and penetrate 12-18 inches.

The beauty of this set of criteria is that you don't have to worry about temporary or permanent stretch cavities,as you get a complete energy dump into the target in a specified range of penetration. You can establish the minimum energy acceptable for a round and a check it through simple calculations of bullet weight and velocity.

Your average CCW doesn't necessarily need a round like this, but LEO's do. The testing, however is expensive. Unlike your typical youtube tester, the blocks of gel are calibrated by a pretty expensive machine, and numerous blocks at uniform temps are used to test each round type to determine uniformity across a sampling of rounds. It's no big surprise that small and medium sized PD's tend to follow the FBI, LAPD and NYPD ' s lead, since it is a lot cheaper than doing their own testing.

 

[OldMarksman]

^^^^^^^^^

Good input, for those who have not studied the subject.

 

[1-DAB]

and why i carry ammo that has passed the FBI tests.

 

[SocialAnarchist]

And yet after the next great shoot out another witch hunt will be launched. Weapons and ammunition will be blamed, yet again, and a whole new round of expensive testing will ensue.

Sorry if I seem cynical, but...I am.

 

[mavracer]

"as what is directly in the path of the bullet."
"The wound path of the projectile is known as permanent cavity"

You do realize the bullet is the projectile.

Now, this is beyond my knowledge base, but I have been told that a .38 LRN bullet will create a smaller permanent wound channel than will a .38 wadcutter or semi wadcutter bullet with the same diameter and the same penetration.

Of course meplat matters and better penetration models will take that into account, of course alao if they are the same weight and velocity a larger meplat will penetrate less.

A JHP? Still larger.

and even less penetration.

Of course it is energy that causes the bullet to expand! Of course JHP bullets have holes in them! And just where do you think that heat comes from?

Momentum can not change form energy can if two bullets have the same momentum and one has more energy they will make similar size permanent cavitys and the one with more energy will make a larger temporary cavity (elastic energy) it'll also produce more heat (heat energy) and make a louder smack (sound energy).

That would seem self evident, though again, it is reported that forensic pathologists often cannot distinguish among them after real shooting incidents.

If the size of the hole doesn't matter then why not a 32?

The question is how important that is, and how that importance compares to that of additional hits.

Might be all the difference in the world if the additional hit is four minutes later a la '86 Miami

 

[4V50 Gary]

JollyRoger - I didn't know the FBI had HK MP-5s in 10 mm. Those MP-5s are the ideal caliber for the woods.