Temporary Cavitation Wounding. Rifle vs. Pistol?

[StanBan87]

Hi folks, I have a question for the experts: what is the threshold for temporary cavitation wounding? If it makes it easier, specifically with a bullet with a .355 diameter in the 65-90gr range?

To give a little context, I was reading this thread on M4carbine (https://www.m4carbine.net/showthread.php?209008-Beyond-service-pistol-calibers) which indicates that one of the biggest reasons traditional rifle rounds have much more dramatic wounding in many cases is because of "temporal cavitation wounding" in which there is enough energy and surface area that the temp cavity is moving at velocities which induce actual wounds (first assumption this is predicated on). The consensus seems to be that velocity is more important that mass or size, although those do matter. The other consensus seems to be that once you get rifle projectiles up around 1800-2000fps, this effect starts in earnest. One guy then pipes up that there are some pistol rounds that match or are close in terms of velocity to 5.56 from 10-12in barrels, with similar kinetic energy as well. This reminded me of another thread I'd seen recently on Glock Talk (https://www.glocktalk.com/threads/38-casull-glock.1682573/page-4) where a guy has revived 38 Casull and is pushing light bullets very fast.

In sum we have a .357 SIG pushing 65gr 9mm bullets at over 2100fps, a 9x25 Dillon pushing 80gr TACXP's at over 2100fps, and .38 Casull pushing 90gr XTPs at over 2400fps! Which if any of these might be fully into the "rifle" wounding category?

And the followup: how temp cavity wounding scales with bullet diameter and KE as well as velocity in general? I realize that is asking a lot broader of a question so I narrowed the question above. Thanks!

[Sensei]

Significant temporary cavitation generally occurs at velocities >1400 fps. The problem with most ultralite, ultrafast pistol rounds is that they are poorly constructed. This leads to temporary cavitation in the first 4” of issues and trival temporary or permanent cavities beyond 8-10”. Performance through many intermediate barriers is horrible.

Contrast this with well-designed rifle rounds that offer significant temporary cavities out to 8-10” and a reasonable permanent cavity(ies) out to 16+”.

[BehindBlueI's]

Paging DocGKR

[DocGKR]

"what is the threshold for temporary cavitation wounding?"

Depends.

At LAIR, shots were made in the 6000-6500 fps range and the TC was minimal--like a .38 sp LRN for those projectiles which remained point forward.

Shotgun slugs and large caliber deforming rifle projectiles (think old school 1800's era calibers) can have velocities below 1500 fps, yet offer quite impressive TC effects.

34845


"If it makes it easier, specifically with a bullet with a .355 diameter in the 65-90gr range?"

As noted, when driven too fast, many expanding projectiles designed for handguns will: over-expand creating too much drag resulting in reduced penetration; hyper-expand and fragment, resulting in limited penetration and poor terminal effects; or cause the expanded petals to fold back against the bullet shank, creating a wadcutter type effect (this often occurs with all copper JHP's).

This violent perpetrator took 27 hits of 115 gr JHP at around 1400 fps during an active shooter incident--too much expansion and too little penetration resulted in poor incapacitation effects.

34844

[WDR]

This violent perpetrator took 27 hits of 115 gr JHP at around 1400 fps during an active shooter incident--too much expansion and too little penetration resulted in poor incapacitation effects.



It looks like he still had a very bad day. I'm assuming he didn't survive?

[DocGKR]

Fortunately he did not survive, but he was not easy to stop due to poor bullet performance. NONE of the grossly overexpanded, shallow penetrating body hits reached any vital organs, it was a peripheral neck hit which severed an artery, eventually resulting in hypovolemic shock, unconsciousness, and death.

[WDR]

I think I'd choose a 5.56 rifle over a 9mm SMG every time. Rifles make rifle wounds, and handguns, even ones with stocks and longer barrels, suck.

[Sensei]

It looks like he still had a very bad day. I'm assuming he didn't survive?

I see a bunch of rib fractures and lead with no chest tubes...probably a post-mortum.

[DocGKR]

Definitely post-mortem from Medical Examiners office...

This is one of the seminal incidents that encouraged American SWAT teams to switch from MP5's to AR15's.

[Sensei]

I think I'd choose a 5.56 rifle over a 9mm SMG every time. Rifles make rifle wounds, and handguns, even ones with stocks and longer barrels, suck.

The force is strong with you.

There is very little reason to choose a PCC.

A 8-9” barreled 300blk or 6.8 SPC PDW is within 2” of a MP5K in terms of size and has vastly superior terminal performance through every intermediate barrier...

A 10-11” 556 is within 2” of an MP5N and will eat its lunch if fed RA556B or some other barrier blind load.

I have a bunch of PCCs only for nostalgia and because the Mrs. likes them.

[Balisong]

Definitely post-mortem from Medical Examiners office...

This is one of the seminal incidents that encouraged American SWAT teams to switch from MP5's to AR15's.

That's interesting. As always, I appreciate you sharing your knowledge and expertise with us. I didn't realize there were specific instances that lead to the change. That being said, I do wonder how differently that shooting would have gone if the team had heavier rounds from your list in their MP5s....

[StanBan87]

Thanks for the excellent information Doc and every! I have some followup questions based on what I've learned thus far.

1.) From the example (1500fps slugs vs. 6000fps tiny bullets) I understand that at a given surface area (and KE?) there is going to be a velocity threshold at which temporary caviation wounding beings and it accelerates from there. Depending on the bullet (expansion, weight, etc) this might be low (like the slug), high (like I'm assuming 62gr 5.56 is), or impossible to achieve. So to sort of re-phrase my question from the OP (ignoring bullet construction issue for the moment) approximately what velocity is needed to have .355 or .4005 bullets which are expanding into the .5-.7in range start to show significant TCW similar to that of intermediate caliber rifles? Say for example, a 5.56 SBR pushing 77gr OTMs to 2500fps or similar?

2.) Onto bullet construction, I understand that pistol bullets (like rifle bullets) have a certain velocity window in which they will terminally perform properly. If pushed beyond this window, they will act like a varmit bullet and have very poor penetration. For these particular pistol bullets specifically, it does seem that limits you to the solid-copper and similar HP designs like the Barnes TACXP. As you point out Doc, these have a tenancy to have the petals fold back against the body at higher velocities. The two tests I could find certainly showed as much: #1 (https://www.shootingillustrated.com/articles/2011/8/8/9-mm-doubletap-80-grain-tac-xp/), #2 (https://www.youtube.com/watch?v=RCXyD3RBH0Y). That does still seem to leave the bullet somewhat expanded however, seemingly in the .5in-.6in range (https://www.luckygunner.com/labs/self-defense-ammo-ballistic-tests/#9mm). At least at 1550fps the 80gr TACXP still seems to be meeting the FBI spec as well. Not apples to apples, but so does the 125gr TACXP when shot at ~1500fps in 10mm (https://www.youtube.com/watch?v=9xHxdPxE-dE). If this performance (level of expansion and penetration) continue up to the 1900-2100fps range (as both barnes and DT assure me it will, and if it doesn't the 95gr or even 115gr TACXP could be used instead), it seems they would be an effective answer? Or am I missing something that invalidates this theory?

3.) I don't want to derail the thread, but the other bullet that would supposedly work are the Lehigh Xtreme Defenders (what a name...). I used the search function and came up with some conflicting comments. It seems highly contentious all over the net if they work or not, if the gel results are good but aren't replicated in actual tissue/organs, etc. Since we are talking here about launching them at 2000-2400fps, would that change anything?

Thanks again, this form is such a wealth of knowledge :).

[DocGKR]

1. Sorry, you can’t really separate out bullet construction, length, weight, etc… from the analysis. Assuming an expanding .355 projectile was engineered to perform optimally at a higher velocity, one would likely start to see increasing TC effects beyond 1600 fps and certainly by 2000 fps. But again, there are a lot of parameters at work; for example, we see a larger TC with most .44 Mag handgun projectiles than for .357 Mag projectiles, even when the .357 are going a bit faster. FWIW, 77 gr OTM yaws, hyper-expands, then fragments which is a different mechanism than a relatively stable expanding projectile which does not yaw--like most handgun JHP designs.

2. An effective answer for what? As noted, many times when solid copper HP’s are driven beyond their design parameters, the expanded solid copper “petals” fold back over the shank or fracture off. But sure, a solid copper HP could work well, if designed correctly and operated within the correct velocity range. Beware, there can be more “empty space” between the expanded “petals” than on an expanded JHP bullet. Also, make sure the RD measurements are done correctly, many I’ve seen on the internet are done improperly: https://pistol-forum.com/showthread.php?4333-Ordnance-gelatin-test-assessment-for-rifle-and-pistol-calibers&p=75136#post75136. Oh, for that matter, it seems a lot of hobby gel shooters incorrectly describe the TC as the PC, based on what I am seeing on YouTube (ex. https://www.youtube.com/watch?v=sBSl7CDkMNA)…

3. The Lehigh Xtreme Defenders are a solid projectile that act like most FMJ handgun projectiles with a yawing effect. With higher velocity the TC will be a bit larger as the solid bullet yaws, but because a handgun projectile is generally much shorter than a rifle bullet, the TC is typically smaller than for an equivalent weight rifle bullet.

[Tokarev]

For these particular pistol bullets specifically, it does seem that limits you to the solid-copper and similar HP designs like the Barnes TACXP. At least at 1550fps the 80gr TACXP still seems to be meeting the FBI spec as well.

I messed with some 80gr copper HP's loaded to higher-than-designed velocities. I wasn't quite able to get to the 12" mark in gel. Soft recoil, however. Such a load might be of consideration to someone who's overly sensitive about recoil.



https://pistol-forum.com/showthread.php?29829-High(er)-Velocity-380-Bullets-in-a-9mm-Do-They-Work

[StanBan87]

Thanks Doc, really informative post as always :).

One last question, what is the ~temp cavitation wounding velocity needed for things like the 62gr bonded bullets (like the Fusions) in 5.56? They expand to pretty low velocities, so I'm curious if their impact velocity was low enough they much still expand OK but be going slow enough not to induce temp cavitation wounding.

[Sixgun_Symphony]

Some threads from m4c.net readers here might find interesting on similar topics, while not completely relevant to the original question asked

https://www.m4carbine.net/showthread.php?95230-Barrier-Blind-vs-Fragmentation

https://www.m4carbine.net/showthread.php?94000-Solid-Copper-and-Bonded-Rifle-Bullets-Produce-Less-Wound-Trauma

https://www.m4carbine.net/showthread.php?49828-Is-ft-lbs-of-energy-relevant-anymore

https://www.m4carbine.net/showthread.php?92950-Barrier-blind-5-56-loads-negating-the-strengths-of-the-carbine-*


Every Issue of IWBA Wound Ballistics Review Available Online
https://drive.google.com/drive/folders/0B_PmkwLd1hmbd3pWYVVJeGlGaFE

[Jeep]

The force is strong with you.

There is very little reason to choose a PCC.

A 8-9” barreled 300blk or 6.8 SPC PDW is within 2” of a MP5K in terms of size and has vastly superior terminal performance through every intermediate barrier...

A 10-11” 556 is within 2” of an MP5N and will eat its lunch if fed RA556B or some other barrier blind load.

I have a bunch of PCCs only for nostalgia and because the Mrs. likes them.

Old school might work too--buckshot, slugs and 30-30's (and for real old school, .351 Winchesters). Its hard to send as much lead downrange with them . . . but then you might not need to send as much lead downrange.

[DocGKR]

Don't forget old school USGI M1 carbines w/quality expanding ammunition--they are far more terminally effective than a PCC.

[Jeep]

Don't forget old school USGI M1 carbines w/quality expanding ammunition--they are far more terminally effective than a PCC.

Absolutely--if you can keep the gas piston functioning in them (my luck has only been so-so with that--some of those carbines are seeing their last days). I think a .357 carbine is also more effective than a normal PCC. You can get a good 158 grain soft point round going 1800 fps, though you are limited to lever action.

[Nephrology]

This violent perpetrator took 27 hits of 115 gr JHP at around 1400 fps during an active shooter incident--too much expansion and too little penetration resulted in poor incapacitation effects.

34844

That's an amazing plain film. Do you mind sharing more info about this event?

[StanBan87]

Ok folks, resurrecting this thread with new information. DoubleTap is now making 77gr SCHP (solid copper hollow points) in 9x25 Dillon that are going ~2100fps from a 6in barrel or about 2015fps from a 4.5in barrel. You can see a gel testing comparison between the 80gr Barnes discussed above vs. the new 77gr SCHP here (https://www.youtube.com/watch?v=UVATzyfCXgM). The 80gr is going a bit slower, but sheds peddles at 2000fps+ as Doc surmised it might. The 77gr SCHP has been designed properly for such high velocities and does not shed peddles, and has impressive penetration and expansion. I have since bought a drop in barrel and dies to test 9x25 Dillon (which is a ton of fun) and am getting the 77gr SCHP to around 2100fps from a 4.5in barrel with handloads.

In light of this new information my question for the experts here is: Is a 77gr .355 bullet traveling at ~2100fps that expands to around .66in and penetrates to around 14in creating temporary caviation wounding similar to smaller rifle rounds (like say a 62gr expanding soft point from a 10.3in AR)? Based on Doc's answer above my guess is "yes" but I wanted to confirm since I am no expert.

On a similar note, is there any way to tell if a bullet is causing TCW as a layman with ballistics gel? That is about all the testing I can do myself.

[John Hearne]

I have it on good authority that 9x23 delivers wounds that more greatly resemble rifle rounds than pistol rounds. IIRC, the load in question was running in that 1800-2000 fps window.

[spyderco monkey]

Ok folks, resurrecting this thread with new information. DoubleTap is now making 77gr SCHP (solid copper hollow points) in 9x25 Dillon that are going ~2100fps from a 6in barrel or about 2015fps from a 4.5in barrel. You can see a gel testing comparison between the 80gr Barnes discussed above vs. the new 77gr SCHP here (https://www.youtube.com/watch?v=UVATzyfCXgM). The 80gr is going a bit slower, but sheds peddles at 2000fps+ as Doc surmised it might. The 77gr SCHP has been designed properly for such high velocities and does not shed peddles, and has impressive penetration and expansion. I have since bought a drop in barrel and dies to test 9x25 Dillon (which is a ton of fun) and am getting the 77gr SCHP to around 2100fps from a 4.5in barrel with handloads.

In light of this new information my question for the experts here is: Is a 77gr .355 bullet traveling at ~2100fps that expands to around .66in and penetrates to around 14in creating temporary caviation wounding similar to smaller rifle rounds (like say a 62gr expanding soft point from a 10.3in AR)? Based on Doc's answer above my guess is "yes" but I wanted to confirm since I am no expert.

On a similar note, is there any way to tell if a bullet is causing TCW as a layman with ballistics gel? That is about all the testing I can do myself.

Thats a very interesting 9x25 load.

In terms of 'rifle effect,' a 77gr @ 2100fps / 754 ftlbs.

By comparison, a 10.5" 75gr .223 Gold dot is 75gr @ 2240 / 836 ft/lbs. 2100fps is what that round would be doing at ~60yds.
https://www.ar15.com/forums/ar-15/Suppressed-5-56-SBR-Velocity-Tests-41-Factory-Loads-from-10-5-11-5-12-5-and-14-5-ALL-DONE-/16-714088/

I would say there's every reason to expect that the 9x25 would be comparable to the 75gr Gold dot @ 60yds/2100fps.

Since we have no 9x25 data, its worth looking at one of the most prolific high velocity handguns, the 125gr .357, which suggests that handguns below 2000fps can begin to produce some element of 'rifle like effect.'

Handgun hunters have found .357 @ 1300-1600fps to perform "disproportionate to caliber."

As a general guide to performance, the .357 can produce quite spectacular kills at impact velocities of 2000fps and faster using hollow point projectiles.

At impact velocities of 2000 to 1600fps, game hit with a fast expanding hollow point tend to react in a drunken manner, often attempting to run but not generally making too much ground before succumbing quickly to blood loss.

Between 1600 and 1300fps, dead runs may be longer but wounding is still somewhat disproportionate to caliber. Again, bullet weights must be matched to the job at hand. If the bullet is too heavy, it may not meet enough resistance to render a wide wound at low velocities. If the bullet is too light, it may not have enough energy to render a deep and broad wound on larger bodied animals.

At impact velocities of 1200fps and below, bullet expansion may be fully evident, yet wounding can be narrow (proportionate to the expanded caliber of the bullet) and blood trails poor. At these velocities and in the absence of any major hydraulic force, the .357 is reliant on mechanical wounding, the size of the wound being directly proportionate to the diameter of the expanded bullet.

https://www.ballisticstudies.com/Knowledgebase/.357+Magnum.html

There are other accounts, less formal, of .357 125gr @ 1450fps providing much more effective against hogs / deer then 124gr 9mm JHP, despite their expanding projectiles being identical in size. This suggests some additional X effect due to the increase in velocity and energy.

And in the calibers studied in 1 year of Boston police shootings, .357 also showed a disproportionate effect relative to other handgun calibers:
https://i.ibb.co/qCLC7RB/Screen-Shot-2020-01-18-at-8-54-18-AM.png

Caveat emptor, this was a flawed study, in that it includes 100% of bostons homicides, but only a % of the woundings, selected at random. Still, this bias would effect all the calibers, making the unusual ratio displayed by .357 noteworthy.

Finally, Brassfetcher has done one of the best studies to date on temporary cavitation:
http://www.brassfetcher.com/Wounding%20Theories/Velocity%20of%20Radial%20Expansion.html

Pistol cartridges including .22LR, .32ACP, .380ACP, 9x19mm, .40S&W, .45ACP, .357 Magnum, .44 Magnum JHPs as well as 22 K-Hornet, 223 Remington, 260 Remington, 308 Winchester and 30-06 Springfield rifles were evaluated in 20-percent ballistic gelatin and the results recorded on high speed video. From these videos, analysis was conducted of the velocity and instantaneous kinetic energy of the point of maximum temporary cavity diameter for each shot.

It was found that the magnitude of kinetic energy present at any point during the expansion was directly attributable to the initial velocity of the projectile at impact. Expanded diameter appeared to play little, if any role in influencing temporary cavity diameter. Handguns such as 9x19mm and .40S&W appear to be the lower threshold for wounding through tissue expansion, with .357 Magnum a marked improvement over the two. Rifles of moderate recoil demonstrate impressive tissue expansion upon bullet impact.

All of this is to say, that 9x25 load has a lot of potential, as do other high velocity loads like some of the full power .357 sig's loaded by Underwood (125gr @ 1525fps from a 4.5" / 65gr @ 2100fps.)

[BehindBlueI's]

Ok folks, resurrecting this thread with new information. DoubleTap is now making 77gr SCHP (solid copper hollow points) in 9x25 Dillon that are going ~2100fps from a 6in barrel or about 2015fps from a 4.5in barrel. You can see a gel testing comparison between the 80gr Barnes discussed above vs. the new 77gr SCHP here (https://www.youtube.com/watch?v=UVATzyfCXgM). The 80gr is going a bit slower, but sheds peddles at 2000fps+ as Doc surmised it might. The 77gr SCHP has been designed properly for such high velocities and does not shed peddles, and has impressive penetration and expansion. I have since bought a drop in barrel and dies to test 9x25 Dillon (which is a ton of fun) and am getting the 77gr SCHP to around 2100fps from a 4.5in barrel with handloads.

In light of this new information my question for the experts here is: Is a 77gr .355 bullet traveling at ~2100fps that expands to around .66in and penetrates to around 14in creating temporary caviation wounding similar to smaller rifle rounds (like say a 62gr expanding soft point from a 10.3in AR)? Based on Doc's answer above my guess is "yes" but I wanted to confirm since I am no expert.

On a similar note, is there any way to tell if a bullet is causing TCW as a layman with ballistics gel? That is about all the testing I can do myself.

DocGKR

[the Schwartz]

deleted

[the Schwartz]

Interesting thread...

The problem with using very light-weight projectiles (even if they retain most—or all—of their initial mass) even if they are launched a very high speeds (approaching 1,600 fps from a pistol) is that they are simply incapable of producing the minimum 12 inches of penetration needed to ensure that critical organs and CNS are struck if/when barriers are encountered.

Here are some tests conducted this summer that illustrate the issue:

July 10th, 2019
89° Fahrenheit
49% Relative Humidity
Moderate over-cast skies
653 feet ASL


1.) Corbon 9mm 90-grain JHP (control)

Test Firearm: Glock 17; 4.49-inch barrel
Barrier: None
Test Medium: H₂O

Average Recovered Diameter: 0.524 inch
Retained Mass: 42.6 grains
Impact Velocity: 1,455 feet per second

47400

47401

47402

Predictive Analysis:

Q-model
DoP: 6.162 inches
Wound Mass: 0.654 ounces
Wound Volume: 1.089 cubic inches

mTHOR model
DoP: 6.181 inches
Wound Mass: 0.656 ounces
Wound Volume: 1.092 cubic inches


2.) Corbon 9mm 90-grain JHP vs. 4 layers of 16-ounce denim

Test Firearm: Glock 17; 4.49-inch barrel
Barrier: IWBA 4LD mechanical failure test protocol
Test Medium: H₂O

Average Recovered Diameter: 0.4895 inch
Retained Mass: 44.3 grains
Impact Velocity: 1,448 feet per second

47403

47404

Predictive Analysis:

Q-model
DoP: 7.414 inches
Wound Mass: 0.687 ounces
Wound Volume: 1.143 cubic inches

mTHOR model
DoP: 7.340 inches
Wound Mass: 0.680 ounces
Wound Volume: 1.131 cubic inches


3.) SuperVel 9mm 90-grain JHP (control)

Test Firearm: Glock 17; 4.49-inch barrel
Barrier: None
Test Medium: H₂O

Average Recovered Diameter: 0.515 inch
Retained Mass: 47.5 grains
Impact Velocity: 1,524 feet per second

47405

47406

Predictive Analysis:

Q-model
DoP: 7.312 inches
Wound Mass: 0.750 ounces
Wound Volume: 1.248 cubic inches

mTHOR model
DoP: 7.384 inches
Wound Mass: 0.757 ounces
Wound Volume: 1.260 cubic inches


4.) SuperVel 9mm 90-grain JHP vs. 4 layers of 16-ounce denim

Test Firearm: Glock 17; 4.49-inch barrel
Barrier: IWBA 4LD mechanical failure test protocol
Test Medium: H₂O

Average Recovered Diameter: 0.518 inch
Retained Mass: 49.4 grains
Impact Velocity: 1,520 feet per second

47407

47408

Predictive Analysis:

Q-model
DoP: 7.499 inches
Wound Mass: 0.778 ounces
Wound Volume: 1.295 cubic inches

mTHOR model
DoP: 7.576 inches
Wound Mass: 0.786 ounces
Wound Volume: 1.308 cubic inches


5.) DoubleTap 9mm 80-grain TAC-XP (control)

Test Firearm: Glock 17; 4.49-inch barrel
Barrier: None
Test Medium: H₂O

Average Recovered Diameter: 0.574 inch
Retained Mass: 80.0 grains
Impact Velocity: 1,451 feet per second

47409

47410

47411

Predictive Analysis:

Q-model
DoP: 9.472 inches
Wound Mass: 1.207 ounces
Wound Volume: 2.008 cubic inches

mTHOR model
DoP: 9.654 inches
Wound Mass: 1.230 ounces
Wound Volume: 2.046 cubic inches


6.) DoubleTap 9mm 80-grain TAC-XP vs. 4 layers of 16-ounce denim

Test Firearm: Glock 17; 4.49-inch barrel
Barrier: IWBA 4LD mechanical failure test protocol
Test Medium: H₂O

Average Recovered Diameter: 0.560 inch
Retained Mass: 80.0 grains
Impact Velocity: 1,471 feet per second

47412

47413

Predictive Analysis:

Q-model
DoP: 10.071 inches
Wound Mass: 1.221 ounces
Wound Volume: 2.032 cubic inches

mTHOR model
DoP: 10.246 inches
Wound Mass: 1.243 ounces
Wound Volume: 2.067 cubic inches

DoP = maximum equivalent depth of penetration in 10% ordnance gelatin (or soft tissue)
Wound Volume = total volume of the permanent channel
Wound Mass = total weight of tissue damaged/destroyed within the permanent wound channel


As can be seen in tests #2 and #4, the light-weight JHPs of conventional "cup and core" construction (CorBon and SuperVel) lost approximately one-half of their initial mass (on average) reducing their ability to penetrate adequately (≥ 12 inches). Predicted penetration in the 4LD tests for the "cup and core" JHPs averaged just 7.45 inches.

In test #6, the Barnes 0.355" all-copper monolithic TAC-XP 80-grain hollow point at 1,471 fps as loaded for the 9x19 by DoubleTap, retained 100% of its mass, yet its predicted maximum penetration—while better than that of the conventional "cup and core" JHPs—still fell far short of the 12-inch minimum which an average modeled prediction of just 10.159 inches.

Penetration of bullets in gelatin (and bodies) is a function of momentum: mass times velocity.

Adequate mass is needed to ensure that the bullet can penetrate adequately. No ''free lunches''.

[StanBan87]

spyderco monkey yes that is what I'm figuring as well. At least in the case of the 9x25 Dillon with the 77gr SCHP @ ~2100fps, I see no reason why it wouldn't be wounding about the same as that 75gr Gold Dot from a Mk18 or similar at around 50y. But I am no expert hence my question. If it is true, then I have to say that it is a real honest "game changer" (for once that term actually applies) for the pistol world. You can CCW 10+1 (or more with mag extensions) with a G29, which is about the size of a G19. If this proves to be true, you are basically getting Mk18-ish performance to EDC in an ultra-reliable G19 size semi-auto pistol with basically the same recoil as quality .40S&W 165gr loads (no joke run the numbers). I don't think there is basically anything else that can give rifle (all be it the low end of rifle) TCW and is concealable, reliable, and/or doesn't recoil like crazy.

the Schwartz Did you watch the testing video? The 9mm loads using both the 80gr Barnes and 77gr SCHP fail to get much past 10in as you would expect (around 1600fps I believe). But the 9x25 Dillon has a MV of around 2100fps with both bullets, and both go about 13-14in in the blocks. Hardly a definitive test, but they certainly seem to be reaching good levels of penetration with the 9x25 Dillion which is the only interesting part of this really as that is the only one going fast enough to cause serious TCW as far as I can tell.

I am going to get some gel made up next month to do some of my own testing unless the experts here shoot this down. I'm hoping others can test as well as some of yall will likely do it much better than I can. You just need a 10mm pistol (like a G20) and a conversion barrel, that's it basically for the pistol.

[ranger]

My head hurts just thinking about 9x25 anything - I remember when they hit the competition world - I hated ROing around those.

[BehindBlueI's]

the Schwartz Did you watch the testing video? The 9mm loads using both the 80gr Barnes and 77gr SCHP fail to get much past 10in as you would expect (around 1600fps I believe). But the 9x25 Dillon has a MV of around 2100fps with both bullets, and both go about 13-14in in the blocks. H

I watched the video. Clear gel testing only from what I saw.

[StanBan87]

I don't really want to get the thread off track, the wounding is what we are here to talk about. But I do want to address the whole "blast" thing with 9x25. What I've found from my 4.5in barrel is that the blast is no worse than hot .357sig when using good modern powders. I think the old competition guns running huge comps/brakes and specifically running powders that generate a lot of gas to effectively use those brakes is what gives it such a bad rep. Honestly going through a few mags of proper 10mm is more abrasive all around than a few mags of 9x25 Dillon.

Can confirm pretty big fireballs, though nothing any ported/comped guys would write home about.

As for the video, yes it seems they used both clear and real gel, but had the clear block out front. The 13-14in in clear gel seems to be pretty representative of actual performance in real gel (it is my understanding that if anything in clear you will get a little less penetration on average), but like I said more testing needed. I just wanted to be sure he knew that from preliminary results it doesn't look like underpenetration is going to be an issue with the 9x25 77gr load.

[DpdG]

As for the video, yes it seems they used both clear and real gel, but had the clear block out front. The 13-14in in clear gel seems to be pretty representative of actual performance in real gel (it is my understanding that if anything in clear you will get a little less penetration on average), but like I said more testing needed. I just wanted to be sure he knew that from preliminary results it doesn't look like underpenetration is going to be an issue with the 9x25 77gr load.

“Looking first at the bare gelatin results, on average, the sampled bullets penetrated 35.5% deeper into the clear synthetic product than they did in the organic, 10% calibrated gelatin, with a range between 34.4% (the 135+P Hornady Critical Duty) and 36.3% (the standard pressure, 124 grain Federal HST).”

Source:
https://www.policeone.com/police-products/firearms/accessories/ammunition/articles/ballistic-gelatin-comparisons-part-iii-IbjkEYB93TAd5o6J/

[Doc_Glock]

Shotgun slugs and large caliber deforming rifle projectiles (think old school 1800's era calibers) can have velocities below 1500 fps, yet offer quite impressive TC effects.

34845



Does the temporary cavity of the .45-70 contribute significantly to incapacitation or is is simply a very large and long drill hole?

[StanBan87]

Very interesting test Dpdg, thanks for sharing. I'm honestly a little shocked, I've always heard the reverse and at least in my lay observations of side by side testing the penetration seems pretty similar between gels, just outside of margin of error usually from what I've seen. But this is why I come here.

Seems like the thing to do is to get the 77gr 9x25 loads tested in real gel as I was already hoping to do. I will try to cook some up in the next few months. I hope others who are interested in this potentially pretty exciting project do likewise, the more data the better.

[whomever]

"At least in the case of the 9x25 Dillon with the 77gr SCHP @ ~2100fps, I see no reason why it wouldn't be wounding about the same as that 75gr Gold Dot from a Mk18 or similar at around 50y. "

At the 'assume a spherical cow' level of analysis, which is the boundary of my knowledge, the 77 gr .223 and 77 gr .355 will have very different sectional densities, which is going to affect how/how deep they dump kinetic energy, whether they yaw, yadda, yadda, ...

[Jim Watson]

It sticks in my head that some years ago the Swedish fish and game people did a study.
They concluded that the "pulsatile cavern" became a significant wounding factor at 2650 fps. About what a 140 gr Swedish Mauser is doing, what a coincidence.

[the Schwartz]

the Schwartz Did you watch the testing video? The 9mm loads using both the 80gr Barnes and 77gr SCHP fail to get much past 10in as you would expect (around 1600fps I believe). But the 9x25 Dillon has a MV of around 2100fps with both bullets, and both go about 13-14in in the blocks. Hardly a definitive test, but they certainly seem to be reaching good levels of penetration with the 9x25 Dillion which is the only interesting part of this really as that is the only one going fast enough to cause serious TCW as far as I can tell.

Yes, I did and I want my three minutes and forty-one seconds back.

I'd agree the testing done the video was 'hardly definitive" as it was conducted in Clear Ballistic Gel product which is notable if only for the fact that it fails to represent correctly the terminal expansion, maximum terminal penetration depth, and temporary/permanent cavities of projectiles being testing in it. As a general and well-documented rule, projectiles that are tested in the Clear Ballistic Gel product exhibit less expansion and correspondingly greater penetration depth than that observed in identical testing in properly prepared 10% ordnance gelatin. Often, and quite unpredictably, projectiles also demonstrate the tendency to rebound from their maximum penetration depth by as much as 40% due to the longer duration of the temporary cavity in the Clear Ballistic Gel product. This occurs because the Clear Ballistic Gel product has significantly lower strain-energy storage and loss moduli than does properly prepared 10% ordnance gelatin. For all of these reasons (not to mention that the manufacturer frequently alters the composition, density and tensile strength of their product and that the product's physical-material properties change over time with each remelt/recast cycle), I dismiss out of hand all testing done in the Clear Ballistic Gel product as inaccurate and irrelevant.



As for the video, yes it seems they used both clear and real gel, but had the clear block out front. The 13-14in in clear gel seems to be pretty representative of actual performance in real gel (it is my understanding that if anything in clear you will get a little less penetration on average), but like I said more testing needed.

No testing in the video that you linked to used validated 10% ordnance gelatin. More to the point above (which I made about the Clear Ballistic Gel product's physical-material properties change over time with each remelt/recast cycle) is that the ''backer'' block in the video is actually a heavily recycled block of the Clear Ballistic Gel product that has darkened with contaminants and residue from prior tests as well as being physically altered by the repeated remelting process. This is one of the other issues that plagues the technology (such as it is) and contributes to the wholesale inaccuracy and irrelevance of the Clear Ballistic Gel product in terminal ballistic testing.

If you are going to conduct any testing, I would encourage you to pursue it through the use of a valid tissue simulant. 10% ordnance gelatin and H₂O are the only two mediums at present that are actually suitable for testing. If you are comfortable with the mathematics required to do so, testing in water (H₂O) requires the use of a modified Poncelet penetration to predict penetration depth as it would have occurred in 10% ordnance gelatin. Books detailing such predictive models can be found here:

https://www.amazon.com/Bullet-Penetration-Modeling-Incapacitation-Resulting-ebook/dp/B00L7CSV7E

and here:

http://quantitativeammunitionselection.com/

Of course, there is also "going directly to the horse's mouth" and testing in validated 10% ordnance gelatin. There are P-F members here (@Tokarev) who do so with really professional results; I'd encourage you to look up some Tokarev's work. Of course, using correctly prepared ordnance gelatin also has in its favor the added allure of not requiring the predictive mathematical models mentioned just a moment ago if math is not your thing. :)

[StanBan87]

Definitely sounds like 10% gel testing needs to be done before anything close to definitive can be said. As I said I will be attempting to do so in a few months and I encourage others to do so in the meantime if they can.

[DocGKR]

Hmmmm......drive an all copper bullet beyond it's design velocity and the expanded "petals" fold back or break off, decreasing permanent cavity size and potentially increasing penetration depth.

[Lester Polfus]

As someone who was into 10mm Auto before it sold out and went mainstream, I can tell you that this is not our first rodeo with its bastard stepchild, the 9x25mm Dillon and super light bullets somehow turning it into a hand rifle. We went through this fifteen or so years ago.

It's a really great cartridge if you want to make 9mm bullets blow up and fragment, including monolithic 9mm bullets. There's a world of difference between a 77 grain .223 bullet and a 77 grain .356 bullet.

I've always wondered if someone could get a custom barrel that would allow a person to load the cartridge with .357 revolver bullets. In my thought experiment it seemed like they would feed pretty will as they are being shoved into a 10mm sized chamber. I've toyed with the idea over the years, but wound up just buying a GP100 instead.

Sometimes I go looking for ballistics tests on things that aren't "service caliber" rounds, stuff like .357 loads and etc, and get all excited, then I see it's being done in Clear Gel and I get my sad face.

[Longranger]

As someone who was into 10mm Auto before it sold out and went mainstream, I can tell you that this is not our first rodeo with its bastard stepchild, the 9x25mm Dillon and super light bullets somehow turning it into a hand rifle. We went through this fifteen or so years ago.

It's a really great cartridge if you want to make 9mm bullets blow up and fragment, including monolithic 9mm bullets. There's a world of difference between a 77 grain .223 bullet and a 77 grain .356 bullet.

I've always wondered if someone could get a custom barrel that would allow a person to load the cartridge with .357 revolver bullets. In my thought experiment it seemed like they would feed pretty will as they are being shoved into a 10mm sized chamber. I've toyed with the idea over the years, but wound up just buying a GP100 instead.

Sometimes I go looking for ballistics tests on things that aren't "service caliber" rounds, stuff like .357 loads and etc, and get all excited, then I see it's being done in Clear Gel and I get my sad face.

As the op said, the 77gr Barnes does NOT blow up and fragment at 9x25 dillon speeds. Saying there's a world of difference between two bullets that are the same weight traveling at the same speed doesn't make much sense, especially when you don't say anything to back up that claim.

[Longranger]

Definitely sounds like 10% gel testing needs to be done before anything close to definitive can be said. As I said I will be attempting to do so in a few months and I encourage others to do so in the meantime if they can.

Hey man, did you ever follow through with this project? I'm extremely interested you seem to have found the perfect loading for this round. I'd be very excited to see how it does in organic gel.

[Longranger]

Definitely sounds like 10% gel testing needs to be done before anything close to definitive can be said. As I said I will be attempting to do so in a few months and I encourage others to do so in the meantime if they can.

OP did you ever follow through with this? I'm very intrigued

[Riptide]

Definitely sounds like 10% gel testing needs to be done before anything close to definitive can be said. As I said I will be attempting to do so in a few months and I encourage others to do so in the meantime if they can.

Did you ever get a chance to test this out?