.40 cal on the way out?

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I completely agree that velocity plays a equal, perhaps more important roll than diameter.
If I had the choice between 357Sig and 45acp I'd probably take the Sig.

I'm not sure how so much of this thread has managed to survive off-topic as a muted caliber war, but since we're here...

Pblnac, thanks for sharing your thoughts/experiences on physiology, but the way your looking at the wound math and shot counts is erred.

Assuming a 9mm round that penetrates 14", a .40 caliber that penetrates 12" and a .45 caliber that penetrates 10.5" they will all damage or destroy around 4 cubic inches of tissue.
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Where does this assumption come from?
If found false then all of your math fails to support the notion that the 9mm has the opportunity to travel further and possibly hit a important tissue.

Regardless, the simple cylindrical math used is incorrect.. wound channels are not cylindrical, they are conical and the bullet expansion becomes a much more important variable.

Another way of looking at this is that assuming all good hits with full expansion and 12 inches of penetration for all, 6 hits with 9mm is roughly equal to 5 hits with .40 caliber, which is roughly equal to 4 hits with .45 cal ACP.
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Who here can not get four 45's on target in the same or less time than it takes to get six on target with 9mm?
Self defense shootings are 2-3 rounds on average.
I encourage you to re-work your math using conical calculations and keep the round count limited to a more realistic three.

The total volume of the wound channel is not of primary importance, but rather/only the part of that total wound channel which affects a vital structure, insofar as rapid incapacitation is concerned.
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I think we all have to agree with this. Well said.
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No we dont, the logic is flawed.
Its self-evident that the larger the wound channel, the greater the chances it will affect a vital structure.

Just a thought, but do we have really good contrast data on these rounds' abilities to break various bone structures?
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Good question.
 
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Handgun caliber wound channels are initially conical in the first inch or at most, few inches of penetration. But in the human body there are typically no vital structures within an inch or so of the skin surface, not even considering the clothing barrier.

Once the projectile has fully expanded they are cylindrical. No handgun projectile expands indefinitely and no handgun caliber has sufficient power to create a wound channel of ever expanding diameter in human tissue. They don't even do so in ballistic gelatin. "Temporary" wound channels are meaningless for all handgun calibers.

Sure, using a simple cylinder to estimate volume of tissue damaged by a single gunshot wound is an approximation, but it is a heck of a lot better than using the volume of a cone. I have seen through and through handgun gunshot wounds that traversed all the skeletal muscle of an arm or leg a number of times and know through first hand experience that the channels are not conical (except for the early expansion part). I won't waste time arguing that matter further.

I was not suggesting that a 9mm is going to be "as good" as a .40 caliber because the 9mm is automatically going to penetrate further, although I can see that it might have sounded that way. I was just trying to point out that in a hypothetical situation an additional 2 inches of penetration in the case of the 9mm "makes up for" the smaller caliber as compared to the .40 in terms of volume of tissue damage. So a smaller projectile that does happen to penetrate further can easily "trump" a larger one with less penetration, not so much because of the greater volume of wound channel, but because during that additional inch or inches of penetration, the chance of the projectile hitting and damaging a vital structure goes up substantially. A classic example is the 115 grain Silvertip round that traversed the upper arm and right thorax of Michael Platt, but stopped an inch short of his right heart during the infamous Miami Shootout.

As for whether a shooter can score hits as quickly with .45 cal ACP as with 9mm, I am sure that many here can. As for myself, I shoot 9mm, .40 cal S&W and .45 cal ACP. I would like to think that I am at least average in marksmanship compared to the total population that owns a pistol or revolver for self-defense and maybe even a little above average. Shooting at relatively close "self defense" distances in a non-threatening environment at a totally static target in good light, sure I can probably get 5 or 6 hits with my model 1911 in the same amount of time I can get 6 hits with my Beretta 92FS. In a tense situation in perhaps low light conditions shooting at a moving target that is shooting back, I am not so sure. It seems that quite a few law enforcement agencies are moving back to 9mm, or considering doing so, because their officers are qualifying much easier with 9mm.


While it may be true that many threats might be neutralized with only one or a few shots (or even none at all) there are many exceptions. Two days ago I met a guy shooting at a local range whose friend had been held up and shot 7 times at close range with a 9mm Pb pistol. He survived and was even able to go for help.

Yes, I would certainly agree that what the wound channel happens to traverse is vastly more important than the volume of the channel. There are a number of ways to physiologically incapacitate a person. One can for example fracture a bone or transect major nerves in their dominant arm that renders them unable to shoot, or knock them unconscious with a non-lethal shot to the head that does not penetrate the cranial cavity. One or more penetrating wounds to the chest can result in a pneumothorax that can be incapacitating or even lethal, although it is unlikely to be immediately incapacitating in the case of handgun calibers.

I hear a lot of people making the assumption that a larger caliber is going to be more effective because it is going to result in more blood loss. While this is true to some extent, unless those wound channels traverse major vessels it is going to take a bunch of wounds and some time before the blood loss is great enough for the person to be incapacitated by hypovolemic shock because the amount of tissue damaged is just not that much. I have seen a bunch of people shot multiple times who were not incapacitated, never became hypovolemic, and never lost consciousness.

So in terms of immediate incapacitation assuming equal penetration I would say that the .45 cal ACP is better than the 9mm because a projectile that has expanded to .70 caliber is slightly more likely to damage a critical structure (open a major artery say) than one that has expanded to .60 caliber. But the difference in radius is only .05 inches which is less than 1/16". So it probably isn't going to make a difference very often.
 
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Yeah Marty, just like any of the popular calibers of today will disappear soon. At least it gives space for some to rant:) I issued mod. 19's (later 66's) to officers at my PD and included Remington 125 gr JHP not .357 mag as they, the average officer was totally inaccurate with the hotter round and complained of the noise, sting in their hand and recoil. We had unfortunate occasions to show the .38 round to be effective.
 
What a long thread.... just another caliber war.
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I suppose you could call it that but this discussion has included a number of solid posts with good information, careful theorizing, and generally cordial debate that I've enjoyed more than usual. It is also rooted in the topic and this round's history, which is itself a matter of "caliber war". I know I'm just some guy on the interweb but I've found it constructive: exactly the opposite of comments like this one.
 
It should be noted, that while pblanc's theoretical example regarding penetration between various calibers is a bit of an exaggeration ...

... it is nonetheless true that apples-to-apples comparisons within various product lines usually demonstrate greater penetration with standard 9mm, than with 9mm +P, .357sig, 40S&W or 10mm rounds of the same design type.

"How much" varies of course.

In the Hornady Critical Duty line for instance, consider basic penetration ...
9mm ......... 15.25"
9mm +P ...... 14.00"
.357sig ..... 14.00"
.357mag ..... 14.00"
40S&W ....... 13.50"
45ACP +P .... 14.00"​

I submit that is almost all cases, the difference in penetration is going to be insignificant (regarding incapacitation effects), just as the small differences in expanded diameter will be insignificant in most cases. In other words, there is no objective, evidence-based reason to conclude that one caliber will generally do better than another.

If there is good reason to think otherwise, I am open to instruction.
 
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One might be inclined to attribute changes in the popularity of different cartridges and loads to marketing but since the same people make everything, it doesn't stand to reason. It would be true, however, that manufacturers, particularly gun makers, want consumers to always wanting to buy something new.

Ordinary consumers, on the other hand, may not be that interested in high performance ammunition beyond buying a box or two to have on hand. But buyers for law enforcement and military users may be have other criteria in mind, some not always obvious.

All that notwithstanding, it will be the individual consumer who keeps alive the less popular cartridges. But I wouldn't say the .40 auto is anywhere near being "less popular." Under our more or less free market system, if there is a demand, it will be supplied, one way or another. That doesn't mean it will be cheap or easy to find. Ever tried to find a .41 AE lately? Nor does the fact that a given cartridge was used in large numbers somewhere mean it will be easily available somewhere else. That was true for most of the Eastern Bloc cartridges at one time, some more so than others. But some will become harder and harder to find as the guns that use them become older, just like their owners.
 
Why ignore velocity?
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Because of the illegitimacy of the idolatry of velocity:

http://journals.lww.com/jtrauma/Cit..._of_Velocity,_or_Lies,_Damn_Lies,_and.12.aspx.

Not that velocity should be ignored, but many overweight it. The IWBA (an organization consisting of trauma surgeons, forensic pathologists, and other experts in the area of terminal ballistics) concluded that penetration was first and foremost for handgun effectiveness. Increased velocity does not always translate into increased penetration. In fact, it is not uncommon to see +P ammo with less penetration with the same bullet than its standard pressure counterpart. Depending on bullet design, increased velocity can cause a JHP to expand earlier and wider, thus reducing penetration, sometimes to the point of the round being unreliable.
 
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Handgun caliber wound channels are initially conical in the first inch or at most, few inches of penetration.
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They look conical at both ends, see photo.

Of particular interest to me is the 357Sig vs the 9mm, which of course has the same diameter bullet.
The near-instant and much larger expansion is certainly interesting.

You mentioned that the wound channels are overall cylindrical, I'd say they are by the time the body gets to you, but were very conical immediately following the shooting until the tissue retracted to its approximate original location.

Shoot a big/round rump roast that doesn't make it into the freezer on time.
You can stand there and watch the holes close up.
 
You mentioned that the wound channels are overall cylindrical, I'd say they are by the time the body gets to you, but were very conical immediately following the shooting until the tissue retracted to its approximate original location.

Shoot a big/round rump roast that doesn't make it into the freezer on time.
You can stand there and watch the holes close up.
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Living tissue does not act like dead tissue ... just sayin. Part of the elasticity of most tissue has to do with the perfusion of blood and other fluids. In meat (which has been bled out), tissues are far less elastic.

This is one reason they no longer use cadavers in ballistics testing ... it's a crappy analog for living things. Calibrated gel is actually much closer to real living muscle in terms of viscosity and density. If you shoot a cadaver (even "fresh"), you'll usually get much bigger holes.
 
If you like the 125 grain 357 Sig, and I do, how terribly different can a slightly pre-expanded 135 grain .40 be?
 
Linophile said:
... In fact, it is not uncommon to see +P ammo with less penetration with the same bullet than its standard pressure counterpart. ...
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Validated by the penetration measurements from Hornady I posted earlier.
 
Because of the illegitimacy of the idolatry of velocity:

http://journals.lww.com/jtrauma/Cita...s,_and.12.aspx.

Not that velocity should be ignored, but many overweight it. The IWBA (an organization consisting of trauma surgeons, forensic pathologists, and other experts in the area of terminal ballistics) concluded that penetration was first and foremost for handgun effectiveness. Increased velocity does not always translate into increased penetration. In fact, it is not uncommon to see +P ammo with less penetration with the same bullet than its standard pressure counterpart. Depending on bullet design, increased velocity can cause a JHP to expand earlier and wider, thus reducing penetration, sometimes to the point of the round being unreliable.
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Well crap. I guess I'm going to have to throw away all my rifles less than .45 caliber.
 
No, not primarily. The internecine debate at the Bureau following the 1985 Miami massacre, in which several agents had been killed and/or severely wounded, was over "stopping power" in an autoloading cartridge, as between 9mm and .45 advocates. The .40 didn't even exist then.

The 10mm AUTO, which SA John Hall introduced into the debate in 1987 using his personally-owned Delta Elite, became a third option in the later field-testing of all 3 cartridges under the Bureau's revised ballistics protocols. Those post-Miami protocols placed emphasis on the criteria of "penetration," which the 10mm's superior sectional density and velocity offered in spades. Plus, of the 3 cartridges the FBI FTU tested, the 10mm was deemed to be the most accurate. Sadly, that was not a virtue inherited by its later offspring, the .40S&W.

Hall's fellow FTU agent, Urey Patrick, wrote the Bureau's "Wounding Factors" monograph in which he lays out the various factors the FBI was looking at in selecting handgun ammunition for LE duty use.
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I've read Patrick's report. With the exception of inconsequential errors (eg, saying energy, rather than momentum, is conserved) it's a worthwhile read. It summarizes the state of handgun terminal ballistics science a quarter of a century ago, and I haven't seen anything more recent that dramatically trumps what the scientific and bullet engineering perceptions were then.

Patrick's report does read like a very tactful 9 Luger vs .45 Auto, and it seems to lean toward favoring the latter (eg, given adequate penetration, a big hole is better). That the Agency opted to go with the unmentioned 10 Auto made me assume that capacity tipped the scales in favor of it vs the .45 Auto. But, the Delta Elite is a single stack 1911, so there couldn't be much, if any, capacity gain.

The IWBA put penetration ceilings on their criteria -- 14.0 inches for bare gel and 16.0 inches for "heavily clothed" gel. As I recall, the FBI changed this to 18.0 inches. In the late '80s 9 Luger and .45 Auto JHPs must have been mostly shallow penetrators? Hot 10 Auto loads didn't over-penetrate?
 
Zombietactics makes some very good points. Ballistics gel is a pretty good match for the density and viscosity of live muscle tissue but it does not have the elasticity.

Ballistic gel tends to be lacerated by being driven outward in a radial direction by a rapidly expanding projectile, and the temporary cavitation effect might damage the gel in an area as much as 10 times the diameter of the projectile. Live tissue behaves differently. It simply stretches radially and recoils back sustaining little, if any permanent damage.

The temporary stretch cavity might be a wounding mechanism for high velocity rifle rounds that exceed 2000 fps, but for handgun calibers the only wounding mechanism is the permanent crush cavity which is the tissue actually destroyed by the path of the bullet.

Assuming equal penetration that crush cavity is going to be a little bigger in volume for the larger centerfire handgun calibers, but the difference is just not very great when one considers modern hollowpoint ammunition.
 
pblanc,

Have you seen the penetration tests of the Lehigh Defense Xtreme Penetrator rounds? The gel is heavily damaged in a cylindrical fashion all along the bullet path, but not to a radial degree seen in JHP stretch cavities early on along the bullet path. Is such damage likely enough to be enough to cause substantial damage, or is it just another form of stretch cavitation?
 
Validated by the penetration measurements from Hornady I posted earlier.
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I hadn't seen that. This thread is moving faster than my ability to follow it. That's a good example between the Hornady 9 Luger and Hornady 9 Luger +P, both with the same 135-gr bullet.

I submit that is almost all cases, the difference in penetration is going to be insignificant (regarding incapacitation effects), just as the small differences in expanded diameter will be insignificant in most cases. In other words, there is no objective, evidence-based reason to conclude that one caliber will generally do better than another.

If there is good reason to think otherwise, I am open to instruction.
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I will agree that small differences in penetration will not matter much as long as the IWBA minima are met. The FBI, however, prefers 18 inches of penetration to their revised minimum of 12 inches, but I am not privvy to the rationale the FBI used to modify the IWBA criteria, so in the absence of that info, I'll stick with the scientists rather than the bureaucrats. (I'm a scientist who used to be a bureaucrat, so my decision is rooted in experience and well deserved skepticism.)

As to expanded diameter, I'm going to go with Patrick's FBI report and give the nod to the bigger hole, given equal expansion. For example, your Hornady data show both the 9 Luger +P and the .45 Auto +P penetrating 14 inches. The expanded diameter of the 9 is 0.6 inch, and that of the .45 is .7 in. That equates to a cross-sectional area that is 36% greater for the .45. Using the metric suggested by pblanc, which seems darn good to me, that's 36% more tissue destroyed per inch of vital tissue traversed. That to me seems like it would be a substantial difference.

Another edge the .45 has is, in the case of a less-than-ideal hit, the increased cross-sectional area gives it a better chance of nicking some vital tissues. A single .25 Auto FMJ that nicks the aorta has been known to drop a guy on the spot. Every little bit of an edge helps.
 
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