Where does hydrostatic shock begin?

[Chris Pinkleton]

At what level do handgun wounds incorporate hydrostatic shock as a significant component?

I think we can assume all cartridges are coming from a sub 10" barrel.

I think this is an interesting question since typical handgun cartridges are not supposed to do much of this to flesh, while it seems important in the .223 ,.308, and other rifle calibers.

This is also an attempt to better my question about "where does rifle-level stopping power begin" and the subsequent thread that followed. Of course, hydrostatic shock is hardly the only factor here, but it seems one of the easier varibles to discuss.

This may not become a "anti-M&S" v. "pro-M&S" thread.

A man can hope, after all.

 

[Snowdog]

I wouldn't put any money on expecting hydrostatic shock until you start reaching rifle velocities.

Sorry, I didn't read the other post you mentioned... but I'm not the more knowledgable person on these matters either.

 

[GeorgeH]

There are two aspects of hydrostatic shock. The first pertains to the ability of fluid to radiate the engery of impact. Like when you get hit in the gut with a fist, you feel the pain spread. The second aspect is when the shock wave itself can cause damage. That varies. But you're looking at the need to impact at mach 2 speed and higher (1200-1500 fps min). But don't discount the first as being a valuable attribute of an impact.

 

[Dave T]

Back when I was researching this subject (handgun stopping ability) for my department I read a book entitled "Wound Ballistics" put out by the US Army Medical Corp. Their contention that "hydrostatic shock" was not a factor until the projectil (no specification of what weapon it is fired from) reached high velocity status, which they defined as 2500 fps or more.

Since then I have read other comments that the threshold is more like 2200-2300 fps. Which ever number you want to accept, we're not talking about any normal/practical handgun velocity.

As a case in point, the 30 Carbine round produces something on the order or 1950 fps out of its 18" barrel. That exceeds most all handgun velocities (excepting some odd ball rounds or handloads) and the FMJ 30 Carbine was noted for its "lack" of reliable stopping.

I am convinced that until you get in the range of 2200-2500 fps, velocity is not the panacea many would have us believe. YMMV!

 

[swifter...]

I don't believe you can get there short of about 2500 fps, give or take. 125 gr .357 will do some amazing takedowns, though...
At under "high" velocity, I go with wide wound channels and deep penetration, it works on dangerous game, and oughta work on two legged dangerous...

Look at the old black powder hunters here and in Africa: Not having high velocity available, they got very effective results with BIG slow bullets, well placed.


Hydrostatic shock is, IMHO, like an honest politician: Nice when you get it, but not something you want to bet on...


Tom

 

[Mike Irwin]

Everything I've read of the concept indicates that it's right around 2,200 fps.

Anything below that and you're not getting the effect.

 

[Zorro]

7.62 X 25MM in it's HOT! Communist Gun form.

Shoots through most "Bullet Proof" things too!

 

[Erik]

Hydrostatic shock doesn't come into play with handguns. Not even the handcannons listed.

 

[355sigfan]

Everything I've read of the concept indicates that it's right around 2,200 fps.
END

So at 2199 you’re not getting enough but at 2200 you are. Sorry I don't buy it. The stretch cavity may not be enough to rip tissue at handgun velocities but it is enough to knock the wind out of you, stun you and in other ways stop you for the short term while the other factors like blood loss stop you for the long term. I can hit you in the solar plexus and not damage any organs yet you will go down for a short time. I can hit you in certain pressure points and have the same effect. The stretch cavity does have a effect on stopping power.
PAT

 

[popbang]

The stretch cavity does have an affect, but the problem arises when you try to quantify it. There seem to be an endless number of variables. My opinion is you don't see reliable hydrostatic shock until you get into rifle velocity. I also believe the shape of the bullet enters into the picture.

 

[juliet charley]

PAT -

1. There is a difference between stretch cavity and hydrostatic shock. Hydrostatic shock actually destroys tissue--stretch cavity does not.

2. The solar plexus/pressure point argument is not only old, but it has absolutely nothing to do with the discussion at hand, and it is very weak. Just about any blow to solar plexus or a pressure, even with the old .38 158-grain lead round nose would have the same effect--so it's not a function velocity or energy or whatever. A blow to the solar plexus is by no means guaranteed to be a disabling blow. If you hit the solar plexus, you've missed (or do you aim for the solar plexus?).

3. The absolutely most generous statement you can make about stetch cavity is that is may under some circumstances, with some people have a minor effect on "stopping power."

4. Reading 101. The statement you quoted said, "Everything I've read of the concept indicates that it's right around 2,200 fps" (emphasis added). "Right around" could mean 2199 (or 2150 or 2250)--your sarcasm just makes you appear foolish--and it certainly does NOT mean it could start right around 1400 fps (typical "fast" handguns velocities), does it?

 

[Mike Irwin]

Why I'm even justifying such a moronic post with a response I'll never know, but...

No, Pat, it doesn't kick in at 2,200 fps. exactly. Nowhere did I say anything even remotely resembling that. What part of "right around" weren't you able to grasp?

Hydrostatic shock exists with any traumatic event involving an object striking the body. It's not unlike ripples on a pond when a stone is tossed in. It's the point at which that effect becomes measurable as an effect above and beyond the wound trauma, and at which it contributes to the wound trauma, that is the aspect that is being discussed.

And, as I stated in my original message, everything I've read on the subject suggests that that velocity point is right around 2,200 fps.

 

[Shawn Dodson]

There is a difference between stretch cavity and hydrostatic shock. Hydrostatic shock actually destroys tissue--stretch cavity does not.

Correct! Hydrostatic shock is the static transfer of hydraulic pressure between cells. If the amplitude of the pressure is great enough it can cause cell walls to rupture as the pressure wave is transmitted from cell to cell. The effect is analogous to stomping on a packet of ketchup.

 

[355sigfan]

The solar plexus/pressure point argument is not only old, but it has absolutely nothing to do with the discussion at hand, and it is very weak

END

You may think so but I disagree and many others do too. A bullet striking the torso near the center of the A zone (solar plexus check your anatomy) with high energy will have a simular effect to being punched or kicked in that same area. Also if the blow is hard enough and placed correctly it will stun someone for a period of time. How long depends on a lot of variables.

(Reading 101. The statement you quoted said, "Everything I've read of the concept indicates that it's right around 2,200 fps" (emphasis added). "Right around" could mean 2199 (or 2150 or 2250)--your sarcasm just makes you appear foolish--and it certainly does NOT mean it could start right around 1400 fps (typical "fast" handguns velocities), does it?)

END

Ok so it’s around 2200 fps so 2100 would not work but 2200 fps does. It’s still a weak and foolish concept no matter how it is read.

Tissue does not have to be destroyed for the stretch cavity to have a bearing on stopping power. Now killing power is another subject all together. Beanbag rounds stop people without destroying tissue and without any penetration.

From real world studies it appears that loads with a larger stretch cavity do better than loads that do not if all other variables are equal. Take the 38 special vs. the 357 mag with the same bullet weights. Both have similar penetration and expansion figures yet most seem to view the 357 mag as a much better stopper.

Just because we cannot see from an autopsy how the stretch cavity of a load affected a stop does not mean it did not. Autopsies only tell us what killed not what stopped the offender.


PAT

(Reading 101) Perhaps you should take manners 101. Your lack there of has been brought to your attention before. You could simply have pointed out that I may have miss read the post.

 

[Jim March]

I've also heard that it's somewhere just over 2,000fps, so 2,200 sounds ballpark correct.

But...I'd think that projectile shape must have *something* to do with it?

Consider: back in the Civil War days, they had two basic choices of projectile: the "true spherical round ball" and the "Minie Ball", which was a pointy-nose, flattish-base critter of roughly the same profile as modern .45ACP FMJ, but with a pointier tip. Bores were in the same ballpark in both cases, often .45 or bigger.

They soon found that Minies shot flatter and were more accurate, but didn't have the stopping power of "true ball". Spherical ball had crappy aerodynamics but for the same reason, displaced flesh very well and hence remained popular in revolvers for quite some time, esp. for those intenting to shoot at "across the room distances".

A modern equivelent might be a full wadcutter, or a flat-nosed critter such as Garrett's "wide meplat" style:

http://www.garrettcartridges.com/products.asp

Get something with this sort of shape up past 2,000fps, and I'll betcha good money you'll get more effect than if you ran typical FMJ ball at 2,300 or even more (such as you'd expect of .30Carbine).

 

[blarney]

hydrostatic shock v. stopping power

I may be the dunce here, but I thought hydrostatic shock was a term used to describe the effect a high-velocity bullet had on tissue with fluid in it. I didn't think it had much to do with stopping power. I've always associated stopping power with high-energy handgun rounds that are designed to put someone "down" (or at least make them think about quitting while they're ahead). Hydrostatic shock, however, I've always associated with high-velocity rifle rounds (i.e. sniping) which are not frangible and thus must do their damage to the tissue in other ways. Not exactly "stopping power" but when a sierra-tipped .30-06 boattail turns your insides into Mom's tapioca pudding, well, you won't be winning any marathon's for a while.

 

[juliet charley]

PAT -

The solar plexus/pressure point argument is not only old, but it has absolutely nothing to do with the discussion at hand, and it is very weak

END

You may think so but I disagree and many others do too. A bullet striking the torso near the center of the A zone (solar plexus check your anatomy) with high energy will have a simular effect to being punched or kicked in that same area. Also if the blow is hard enough and placed correctly it will stun someone for a period of time. How long depends on a lot of variables.

Reading 101 (Remedial. The "discussion at hand" is "Where does does hydrostatic shock begin?" Your remark had nothing to do with the subject at hand.

Tissue does not have to be destroyed for the stretch cavity to have a bearing on stopping power.

See remarks above (Reading 101 (Remedial). The subject is hydrostatic shock--not "stopping power." Hydrostatic shock destroys tissue--stretch cavity does not.

From real world studies it appears that loads with a larger stretch cavity do better than loads that do not if all other variables are equal. Take the 38 special vs. the 357 mag with the same bullet weights. Both have similar penetration and expansion figures yet most seem to view the 357 mag as a much better stopper.

See remarks above (re: Reading 101 (Remedial). Nobody (but you) was/is talking about the a "stretch cavities." Have you ever seen a stretch cavity in the "real world?" --Or is it just a phenomenum you can observe in ballistic gelatin?

You could simply have pointed out that I may have miss read the post.

The foolishness and weakness of your remark as been brought to your attention numerous times before by many people on many forums.

 

[Mike Irwin]

I've seen FAR too many people punched, and kicked, full bore in the solar plexus, and shrug it off, to believe the comparison has any valid effect.

Far too many people are shot in the solar plexus region and shrug it off.

If that were truly an effective method of stopping someone, we'd all be carrying bean bag guns.

 

[Chris Pinkleton]

Thanks J.C., I really had hoped that this would be a "hydrostatic shock" thread , not a "stopping power" thread. I thought maybe we could stay away from the typical problems of stopping power threads.

Silly me.

Looks like the consensus is that hydrostatic shock only occurs above 2,000 fps. Does this mean that the hyper-velocity frangibles (MagSafes, etc.) create tissue damage though this mechanism? I'd always thought they produced a bunch of micro-wound tracks, so closely spaced that a small area is effectively shredded.

 

[Jim March]

Blarney: what we're talking about here is a specific effect whereby tissue is shredded out past what's directly affected by the projectile, just due to the "wake" of disruption of the passing round. We're not just talking about tissue being pushed around a bit ("temporary stretch cavity"), we're talking *shredded* in an area similar to the area of a temporary stretch cavity in a slowwer round.

Chris Pinkleton: most frangibles will indeed turn a specific area of flesh into "hamburger" but it's generally not due to hydrostatic shock, but rather "direct contact" between flesh and bits of projectile. Most frangibles in 9mm/.40S&W/.45ACP/.357 aren't crossing the 2,000fps level in handgun calibers - especially not Glasers, and not the Magsafe Defender either. Some are, mind you, I think RCBD has a .44Mag load rated at 2,400fps (110grain!). Even with that, as a frangible the particles will slow down rapidly after the breakup, so any hydrostatic shock effects won't last the entire length of the round's travel. (BUT the area turned into hamburger must be damned impressive nonetheless!)

See also: http://www.rbcd.net/Personal Defense Ammo.htm - and the pics on the home page of this site. Their claim of a cavity from the .44Mag ammo that's 12" wide by 15" deep should probably be taken with a grain of salt, however, I'd suspect this round at .44Mag velocities would indeed hurt. A lot.

Finally, if 2,400fps from a 110grain projectile is possible in .44Mag, why not just use a hardcast wadcutter of that weight and speed? THAT oughta hurt!