.40 Short and Weak

[Raggedyman]

Please read http://www.firearmstactical.com/pdf/fbi-hwfe.pdf particularly page five in regards to temporary stretch cavity. Also refer to the image above.

Interesting study written by Special Agent but not exactly the empirical data I am looking for. 

Not to redirect but a similar argument could be made around actual quantifiable incapacitation results of 9mm & 357 magnum.  As far as diameter goes, almost identical.  What are we left with to explain the quantifiable differences in wounding results?  Mass and speed of the projectile; No?  In gel, I'll bet they'd look similar to others in the picture you posted but the actual results are clearly different.

difference would be, as with the ten mm, the expanded diameters of the projectiles.

Unfortunately, there are no credible studies of "street" r results. Also unfortunately, many people seem to regard the Marshall and Sannow study as something more than pure carp.

[radiotom]

From the gel tests I've seen, it seems like the 10mm has greater permanent cavitation at the beginning of the wound track than the .40. I've also seen this much more dramatically in my wet books testing.

EDIT: Not to mention the expanded slugs pulled from 10mm gel tests have often had an added .2 inches in diameter over the equivalent .40 loading. I'm looking at you, Gold Dots. Some of them almost expanded to an inch, show me a .40 that does that.

You can't normally see the permanent (or "crush") cavity in gelatin or other gel tests. The diameter of the permanent cavity is measured by taking the average expanded diameter of the projectile (  (max expansion+min expansion)/2 ). Volume of the crush cavity is the result of multiplying the previous number by the length of the track.

What you are seeing in the gel is the temporary (or "stretch") cavity. This has no substantive effect on wounding at pistol velocities (<2,000 fps) but looks dramatic in gel. Human tissue (with the exception of brain and liver tissue) can stretch and return farther than gelatin can so the gel shows fractures. Those testers that have high frame rate cameras can often capture the temporary cavity at or near its widest point.

That said, 10mm expanded diameters are typically slightly larger than the same bullet in .40 S&W. Theoretically, that means a larger permanent cavity, but only by a slight margin and then we consider that .45 ACP expanded diameters are typically larger than a similar bullet in 10mm. I know most of you have seen this but it's probably time to take a look again:

You're going to need to explain this post better.

"You can't normally see the permanent (or "crush") cavity in gelatin or other gel tests."
"What you are seeing in the gel is the temporary (or "stretch") cavity."

So the hole I'm seeing is temporary? OK.

And then we have, for the widest point:

"Those testers that have high frame rate cameras can often capture the temporary cavity at or near its widest point."

My understanding is that there is gel that leaks fluid into the temporary cavity showing it aftwards and others that require a high speed camera to see. The resulting hole, that is sitting there in the gel at the end is the permanent cavity. People cut open gel blocks and measure it sometimes...and since the gel is a tissue simulant, what remains is what remains, permanently. Obvious different types of REAL tissue act different, and obviously higher kinetic energy transfer equals bigger temporary cavities and this is normally only useful to measure in rifles. Nobody is disagreeing with that. But, the cavity that remains in ballistic gel is often much larger with 357 mag and 10mm than their caliber cousins, specifically where the hollow point starts opening up and dumping it's energy. A hole remains after it is said and done, much like a fragmenting M193 in gel. That hole is not temporary. I don't think anybody is saying that, are you? When you hear people like tnoutdoors9, mrgunsngear, shootingthebull or anybody else examining their gel blocks, they always refer to the hole that remains as permanent. You seem to be disputing this.

EDIT:
Here is what I'm talking about:
https://www.youtube.com/watch?v=SPzxBJSIaGA
The same principle applies to handguns. What remains is permanent, the "bubble" as he calls it in this video is the temporary cavity. Obviously, really small and meaningless with handguns.

Again, start around 5 minutes, at 6 minutes he talks about the difference:
https://www.youtube.com/watch?v=RZPGSiDs5_k

Blowing good sizes holes with 10mm, at 2:16 he calls the cavity permanent:
https://www.youtube.com/watch?v=8X6vNZTbF7s
And why wouldn't he? Same type of gel as the M193, same type of hole.

http://kjg-munition.de/Zielwirkung/Fackler/wund4.gif

Go ahead and compare that 10mm cavity to the 40's from his videos. It's not even close.

[Raggedyman]

Maybe I wasn't very clear. There is pretty widespread misunderstanding of what the temporary vs. permanent wound cavities are and how gelatin works. In the photograph below (10mm Underwood 155 gr Gold Dot), the red lines roughly describe the area of the permanent cavity. It is usually very difficult to see without cutting the block open because it is sort of folded back on itself and the gelatin itself bends light a bit. You may just have to take my word for it, but what you see in photographs isn't very representative of the actual cavity. More importantly, the experts who actually get paid by government agencies to do this sort of work have declared that the permanent cavity is determined by measuring the recovered projectile, not by any measurement of the gelatin, regardless of what some YouTube posters do. I respect tnoutdoors9 but he consistently refers to the temporary cavity he sees in his gel as a permanent cavity. Shootingthebull seems to have a better grasp of the fundamentals.

The green lines in the photograph represent the rough area of the temporary cavity. It is not a "hole" as you describe, but rather a region where the gelatin has stretched beyond its elastic limit and split. When you cut the block apart, it looks very much like a crack in glass. If you look closely at the upper track in the photo, you can see the splits have a sort of spiral pattern to them.

In some tests, notably the photograph I posted above, dye has been added after the fact to help illustrate the size and shape of the cavities. This isn't seen as often nowadays because it mainly just emphasizes the temporary cavity, which is not a primary wounding mechanism in handguns.
ir
I think it's important to note that these aren't just my opinions. They are my own (possibly flawed) interpretation of papers written by experts in the field. I encourage you to do your own research. I strongly recommend reading anything by Dr. Roberts or Dr. Fackler.

It's also worth noting that the stretch cavity DOES start becoming a significant wounding factor somewhere above 2,000 fps, especially when fragmentation is also involved. At the velocity seen with M193 and many other rifle cartridges, the tissues stretch far beyond their elastic limit and split, much like the gelatin does at lower velocity.






That last link is M193. Rifles are rifles and pistols are pistols. You can embed the image by wrapping the URL in  tags like this:

[4949shooter]

Let's not forget the medium velocity 10mm loads which exceed .40 S&W ballistics by 100 feet per second or so.

Would anybody take a 155 grain XTP or Gold Dot at 1280 to 1300 fps for self defense purposes? Not too much recoil or blast, but more speed than a .40 in that weight.

How about a 165 grain bullet at 1250 to 1300? Since most .40 loads in that weight are doing 1150, this is a nice increase in speed and kinetic energy without breaking the bank in recoil, muzzle blast, and wear and tear on your weapon. And if you consider the fact that the 165 in .40 is performing very well on the street, the extra 100 feet per second will presumably do even better.

It's a win - win in my opinion.

Not exactly. There is very little difference in actual wounding between service pistol calibers. A hit with a 9mm has similar effect to a hit with a .45 ACP. There is nothing magical going on. A 165 gr Gold Dot moving 100 fps faster *might* theoretically cut a slightly wider wound channel but in practice that extra 100 fps has no impact on the time to incapacitation. While the extra recoil and blast might not be dramatic, there IS a difference and as I mentioned above, less recoil means faster shooting, which means more holes in bad guys, which means faster incapacitation.

Agree 100% that less recoil means faster follow up shots. This is one of the reasons why I concede that we do not need full power 10mm for defense against human aggressors.

I partly agree what you are saying about the differences in service caliber performance. But I must point out that Load Selection is much more imporant than Caliber Selection.

I think you know what I mean by that.

[Raggedyman]

I would go farther and say that selecting the right bullet is most important. Not all bullets are created equal. Not all JHPs are created equal. With a well designed modern bullet like the HST or Gold Dot, it is important to stay within its design parameters but, as I mentioned above, one of the cool things the 10mm can do is to force a badly designed bullet to perform well, or at least adequately.

[4949shooter]

Just to add to that....the old 9BPLE load (9mm +P+) has put down a lot of bad guys with an old bullet design. It seems that the bullet they (Federal) used was up to the task for that velocity.

Does it take a combination between proper load with the correct bullet? I would say so.

[pacapcop]

I just carry on where im going, time of day and season and usual surroundings. I was a proponent of the 135 Nosler, but took it to 155. Might be a 9mm or .40 requirement.

[Rojo27]

Unfortunately, there are no credible studies of "street" r results. Also unfortunately, many people seem to regard the Marshall and Sannow study as something more than pure carp.

Unfortunately, my natural inclination is usually to question generally accepted wisdom (probably a character defect).  Although I'm sure as hell not a ballistician, medical examiner, terminal ballistic researcher; my personal belief is that a bit more at play than penetration depth and permanent cavity defined by diameter of handgun projectile.  But I've been wrong before.

I'm sure we can all agree that shot placement and bullet design are probably two must important factors in swift incapacitation.

Couple of interesting studies I found after contemplating this discussion.
http://arxiv.org/pdf/physics/0701266v2.pdf
http://arxiv.org/pdf/physics/0702107v2.pdf

[Raggedyman]

I'm personally inclined to rest on the knowledge or wisdom of people that are more familiar with a subject than I am, while maintaining a healthy dose of skepticism. And I agree that of course shot placement is the most important factor.

The first article you link opens with a reference to the discredited Marshall and Sannow "study" and relies heavily on their data set. It loses further credibility in mentioning the Strasbourg goat tests. One interesting oddity was the claim that service pistol calibers have only 20% - 30% less energy than .223 Rem. Do they consider .44 mag or .357 mag to be "service caliber"? It is true that those cartridges have been used in police service but I think most people mean 9x19mm, .357 Sig, .40 S&W, and .45 ACP when they say "service caliber."

The second article was very interesting. Any ethical study of this subject is going to have faults because we can't just shoot enraged criminals in controlled conditions and note the results. In this case, deer are not people and more importantly, the targets are not under the influence of anger, fear, adrenaline, alcohol, or other drugs when shot. It also de-emphasizes the importance of penetration out of necessity.

The prevailing wisdom among ballisticians is that crush cavity is the only significant wounding mechanism in service pistol calibers. I have wondered sometimes if particularly energetic cartridges such as 10mm or .357 mag might sometimes get psychological stops due to the increased pain resulting from their larger temporary cavities. Like a punch in the gut, I think.

[Rojo27]

Brass Fetcher study published a couple years ago.  Although 10mm not specifically tested, several other handgun calibers including .40 were, as well as high energy 357 magnum.

http://www.brassfetcher.com/Wounding%20Theory/Velocity%20of%20Radial%20Expansion.pdf

[gandog56]

I'll put it this way....

....I would not want to be shot by either .40 or 10mm. And I have both. I love using the exact same bullet for both when I reload them. And I'm Deadeye Dick accurate with either.

.40 Cal:



10mm:

[Raggedyman]

Brass Fetcher study published a couple years ago.  Although 10mm not specifically tested, several other handgun calibers including .40 were, as well as high energy 357 magnum.

http://www.brassfetcher.com/Wounding%20Theory/Velocity%20of%20Radial%20Expansion.pdf

Very interesting, thank you for posting. The article isn't very conclusive on the effectiveness of the temporary cavity in regards to incapacitation but it confirms that velocity is the key factor in determining the size of the temporary cavity. It also further underscores the fact that rifles are rifles and pistols are pistols.

[Raggedyman]

I'll put it this way....

....I would not want to be shot by either .40 or 10mm. And I have both. I love using the exact same bullet for both when I reload them. And I'm Deadeye Dick accurate with either.

I don't want to be smacked with a wet diaper but that doesn't make it an effective personal defense tool. I'm not arguing that either .40 S&W or 10mm are ineffective (I own and trust both for carry myself) I just hate that reasoning.

As a matter of record, I don't want to be shot with a BB gun or sling shot or hit with a wiffle ball bat. I don't want you to throw cabbages at me or bags of 45 day old pee. There are a whole host of things that I would not want lobbed at me that would be minimally effective for defense. Do you want to be shot with a .22lr? Does the fact that you don't want to be shot with it make it a good choice for defense?

[gandog56]

Like I said....I would prefer not to be shot by either.

[Raggedyman]

Don't hold your breath waiting for me to volunteer, either.