Hi!
I have heard about the "shockeffect" and "hydrochock" made by the temorary cavitation of the bullet when it is inside the animal.
And I have heard that the temporary cavitation the "temporary hole around the bullet" start when the bullet velocity is over 2650FPS inside the animal!???
So bullets with velocity under the 2650FPS will not make any temporary cavitation in the animal??
And can not make the shock effect?
Is there any bullet velocity limit for the temporary cavitation?
And what do you guys think about the shock effect on animals like the moose??
//OK

Hi!

I have shooted 7 mooses with my .300 win mag. Most of them under 50 meters. I have used Sako's 14.3 g (240 grains) bullets, but that bullet don't function well in so high velocities, the bullet breaks in little parts if it hits bones. Now I use Norma's Oryx (13 g, 200 grains), and that seems to function better. The cannelure is large and bullet is mushroomed well and in one piece even after hitting bone.

I'm not sure what exactly is the "temporary cavitation" you mentioned. The last moose I shot was a calf, distance was about 50 meters. I shot a very good lung shot (just behind shoulder blade). Of course the bullet went through the little moose. The moose still run nearly 150 meters after the shot.

The hydraulic shock was evident: the sheets between shoulder muscles, side muscles and ribbones was bloody mass in a diameter of about 50 cm!

Another moose standed about 120 meters away when I shot it through the heart. There was about 5 cm hole in the heart, and this moose run about 100 meters after the shot. The bullet was found (in one piece) near the elbow. Under the shoulders there was rather lot bloody pulp, but not more than usual (when shot for example with .30-06).

I have shot three mooses in very short distances with sako's 240 grains bullet (the muzzle velocity is about 800 meters), and there have not been so much blood than with Norma's 220 grains Oryx (muzzle velocity about 850 meters, nearly 2800 fps) and short distance.

I didn't mention, that those moose's that I have shot in short distance with Sako's bullets did fall down just after the shot, they did't run more than 5 meters! But the bullets did break in parts after hitting bone. Oryx didn't break!

My best shot was a big moosebull with nice horns. The distance was 20 meters and the moose just rolled over. When I went to the died moose, blood flowed from it's nose like a little river. I shooted about 45 degrees back-side so that bullet hit both lungs and I found into two parts broken Sako's bullet behind the shoulder bone.

Hi. I believe that these theories of "Temporary cavitation" and "Hydrostatic/hydrodinamic shock" are mainly useless. On the field it's much more important a correct bullet placement and a bullet that doesn't loose too much weight on impact. Jukka cited Norma Oryx, that are IMO excellent; I use them since 2/3 years and I shot several boars and a couple of roe deers of different weight and with different bullet placement (chest, head and spine). Everytime I had very good results, quick killings and most of the time, complete penetration; I found few bullets, and they all kept 75-80% of their original weight. I think that a big advantage of Oryx is his flat point, that gives a better knock-down power than a spire point. Furthermore, it's almost impossible to explain (and understand) why sometimes you shoot an animal and it falls on his track, and other times it runs for several meters, even with enormous internal damages. I close my post saying that I had better results with heavy-for-caliber, slower bullets. Unfortunally, I cannot say anything about mooses

There is a very good treatise on this sort of thing called 'shooting holes in wounding theories - a study in terminal ballistics'

In it the author (a terminal ballistician by trade) goes into what actualy kills animals and gives the performance of many different bullets in different calibres.

Put simply animals die by losing blood (if you ignore CNS or skeletal damage) all things being equal you lose blood quicker if the wound channel is bigger. The size of the wound channel is best described as it's volume (ie area multiplied by length)

Temporary cavitation is caused by the tissue moving away from the pressure wave caused by the bullet as it moves through the tissue. The speed with which the tissue moves is greater than it's elasticity can cope with so it is destroyed. I think that this occurs even with bullets travelling as slow as the lower limit for expansion (generaly around 1900fps)

The 2,650fps or thereabout magic number is not the limit below which temporary cavitation does not occur but simply a velocity above which most bullets start to expand more violently and completely. The increased cavitation is not due to the velocity but the effect of the velocity on the bullet causing it to expand more and hence (if penetration continues) a greater volume wound channel.

I have asked for an up to date link for the paper which makes fascinating reading.

Don't try to shock a moose - my 9.3 doesn't even make them flinch but they still die 50yards later

1894mk2,
I read this paper some time ago and indeed it is heavy and fascinating reading.
You are right in what you say about blood loss, it is the sudden loss of blood pressure that incapacitates an animal and before it has time to recover it has bled to death. The temporary wound cavity, which is caused by hydrostatic shock also has a secondary effect in that it shuts down the nervous system, and if the wound is fatal does not allow the animal to recover..

regards

griff

An excellent way to sum it up Griff !

Long ago here on AR, Overkill ( this is the same guy I presume ?? ) had a lot of questions regarding "the setoff of energy in animals" by bullets, wich in turn ended up with a discussion of what "energy" was needed to toppel a moose of it´s feet when hit.

As I recall....( I could defenately be wrong as I now has passed the Big Six O ), one of the conclousions was that you could be just as succesfull toppling a moose of its feet with a 4x4 as with a 460 Weatherby

Its good to see that you are still in that courious modus Overkill

By the way....according to Griff´s sum up, I still prefere to shoot big game with cailibers that make two holes... one in and one out !

Arild,
couldn't agree more, two holes is far better than one, no matter how big the first one is!!


regards
griff

Is hydrostatic shock the same as Anaphylactic shock? (pardon the spelling)

FB

FB

Hydrostatic shock he don't exist except in the minds of quasi scientists.

The sudden collapse of deer not shot in the CNS is due either to transmission of the shock to the CNS via the skeleton (with some evidence that the shoulder blade transmitting more than other areas) or sudden catastrophic blood loss.

Thusly a shoulder shot deer receives shock to the CNS via some transfer plus the bullet expands more and makes a bigger hole in the heart.

Energy does nothing to deer other than be something that denotes bullet velocity and mass - bullets killing better by imparting all their energy to the animal by not exiting is so much bunkum - all it denotes is that the bullet expanded to an extent it didn't exit and that the initial wound channel is likely to be larger.

Griff I agree that 2 holes is better than one but how high those holes are makes much more difference than calibre. My dog has no problem following high lung shot deer but I very rarely see a darn thing!

I believe that it should be more correct to talk about "Hydrodynamic" rather than "Hydrostatic" shock. The impact of a bullet doesn't match with "static" concept.

So the "Hydrostatic shock" is only effective if it hit(or come near) the cns ???

I think the actual term is "Hydrolastic Shock" guys.

Due to the high velocity of the bullet and to a degree the rate it is spinning a caviatation "hole" is created within the body the bullet is passing through. This strike creates a secondary shockwave through any tissue containing liquid (all tissue), if a blood vessel is struck, a shockwave is sent to the brain causing temporary disfunction - although this can be descibed as permanent as the beastie is well on the way to dying through massive internal "displacement" of the main organs at this time.

It is interesting to see the "different" damage so called meat muncher calibres do when compared to others.

A friend who was using a .308 (150g bullet)mv 2800fps and I went out for Roe a couple of weeks ago. We both shot bucks, both being in the reigon of 230yds away, broadside chest shots. I was using a 6.5x284 loaded with 140g SST, MV 2900fps.

The buck I shot sustained minimal damage - the SST passing bettween ribs on egress and exit nipping the heart lung node. Massive internal disruption but very little bruising.

The buck shot with the 308 was in a far worse state, a large amount of bruising to each shoulder, so much so that one had to be thrown away despite the fact that this was also a well placed shot, touching a rib on exit only.

Had I shot this buck with either my 25-06 or 270, I would have expected to see similar damage, I was surprised at the 308, many who use it, say it is meat friendly

quote:

if a blood vessel is struck, a shockwave is sent to the brain causing temporary disfunction

Andy Mass:

This is an intuitive assumption and in no way representative or proven in true wound ballistics.

A projectile can cause wounding in only two ways:

1. Direct crush of tissue, ie tissue directly in the path and contacted by the frontal area of the projectile, it's pieces ( if it fragments or by secondary fragment production as in pieces of bone that gets mobilized by the impact of the projectile)

2. The stretch of the tissue that is caused by the volume displacement of the tissue in front of the projectile as it forces it's way through the target. This tissue stretch is called the temporary wound channel.

The size of the channel is velocity dependent also dependent on the frontal area of the projectile impacting the tissue and important the effect of the stretch on the tissue is dependent on the visco-elastic qualities of the tissue.

If the tissue is elastic the effect is minimal or absent, if however the tissue is water rich and with poor elastic quality such as brain and liver the effect of stretch is huge.

If a high velocity projectile impacts a large blood filled vessel a shock wave is propagated but the elasticity of arteries and veins are such that they can support these waves without rupturing ( unless the arteries are calcified )

A shot to the large vessels adjacent to the spinal column can in theory cause transient damage to the CNS but the effect is likely attributable to the sudden loss of segmental blood supply to the chord. The spinal chord has a built in blood pressure regulator that protects it from any sudden rise in blood pressure. ( Batsons plexus)

The miscoenceptions attributed to "shock waves in tissue are"

1. An over estimation of the effects of high velocity given the two modes as put in points 1 and 2.

2. A gross overestimation of the effect of stretch on tissue with primary viscous visco elastic properties.

3. Attributing wounding and incapacitation on other phenomena ( other than those in points 1 and 2. )

4. a notion that ultra velocity phenomena that are present at trans and supersonic flight are also seen when projectile is in a target.
( this has been disproven in actual tests)

Gerard shows nice pictures of wound on animals: These are fine but unfortunately much of what is shown represents post event phenoemena. A "blood shot" wound is not alwys due to the effect of the shot directly, it is due to massive bleeding after the shot. ( this has been a problem with the interpetation of lung shots on live animals).

If the animal is dead with no circulating blood volume under pressure the wounds would look much different.

ALF

thanks for putting me right in a scientific manner, with fact rather than fiction - I stand corrected and bow to your obvious greater knowledge.

Are you guys talking about the Fackler paper, writen circa 1987?

He was an US Army Surgeon, and the principle reason for his research was to help emergency room truama physicians do less damage to patients by removing less affected tissue.

His fellow doctors in the study found that many tissues heal very well when they are only in the "temporary" wound channel.

Tissue in the primary wound channel, on the other hand, is toast!

Here's a link to the Fackler paper, if you haven't read it, are living in the Northern Hemisphere, and have an overabundance of dark hours to kill...

http://www.rkba.org/research/fackler/wrong.html

enjoy!

friar

Alf, I am not sure I understand what you are saying. We have done the same experiment (as with the 22x64 and 243) with a 220 Swift at 4400fps and a 22.250 at 3700fps. The Swift was loaded with monometal bullets and the 22-250 with jacketed bullets. We took home several kilograms more meat per carcass from the animals shot with the Swift and monometal bullets. There is no doubt about the difference as we are not talking about a small sample. The total number of springbuck and blesbuck thus compared, now runs to about 200 or so.

What would you ascribe the lesser quantity of bloodshot meat to despite the higher speed of the monometal bullets?

.

I have made the following statements based on my observation of wounds caused by bullets of varying construction types:

"The usual connection between bullet speed and meat damage is entirely correct when applied to jacketed lead bullets. The faster you push them, the more they break up on impact and the more meat damage can be expected."

"Speed is blamed for meat damage where it is, in fact, bullet fragmentation that causes meat damage."

"Simply increasing the velocity with a bullet that does not fragment, will result in so little extra meat damage, that it can be ignored."

"The 22x64 has also laid to rest the theory that speed in itself causes meat damage. We have long contended that bullet fragmentation or tumbling is the real culprit."

It seems from your posts here, that I need not rethink any of the above statements and that my field observations and your research on this subject are in agreement.

This is getting very technical!
Here is a Question for Alf and Gerard: when an animal is hit by whatever bullet at whatever speed is there a temporary vacuum directly behind the bullet path and does this collapse the temporary wound channel,if so this will be inflated by atmosperic pressure. Does this rapid collapse and inflation have an effect on tissue..
MY simple analogy of this is the dropping of an object into water the resulting shock wave is only on the surface, however should you increase the velocity substantially the resultant shock wave on the surface is diminished, the path of the object below the surface cavitates and disrupts the surrounding area.

Just a thought

regards
griff

So is it ony the bullet/fragmentation that make damage to the tissue?? not the hydrochock?
//OK

griff,
Again from practical testing, it is my observation that bullets behave in water much as they do in soft tissue, with a very important point to be taken. The bullet will yield and deform in similar manner to the way it deforms in soft tissue but water does not react and behave like soft tissue.

The only worth of water v. bullet experiments is, if the purpose is to study the way the bullet behaves. Drawing any other parallel (water to tissue) is of little value.

quote:

"Speed is blamed for meat damage where it is, in fact, bullet fragmentation that causes meat damage."

Gerrard,

Surely with a given bullet, the speed at which it travels determines the level of its expansion, and at higer velocities over expansion, (fragmentation). The point is that if increasing speed caused fragmentation, which in turn increases meat damage, then increasing speed increases meat damage.

The problem is that at low velocities when increasing speed (by say 50fps increments) there is not enough marginal expansion to cause extra meat damage but this relationship is not linear. At some point an extra 50fps will incur a disproportional increase in bullet expansion and subbsequent meat damage. In efffect the relationship between speed and meat damage exists but it is non linear.

Hence there will be an optimum speed for a given bullets performance, before it starts to cause excess damage.

Now, I'm no reloader or ballistictician (New word... ) butit kinda makes sense in my head.

Just to throw another item into the equation. Surely a round with a given muzzle energy which causes over expansion at short ranges may have slowed sufficiently at 300yds (say) so as not to cause excess damage to the carcass at longer range. would this make sense?



Rgds,
FB

Fallow Buck,
sounds like sense to me!
your comment on the over expansion a short ranges, brings in a previous thread of which was asked "what is the perfect calibre for roe".
My reply was: composition of bullet for a pupose was far more important than calibre, as you have just pointed out..

So the next question should be, is there a bullet that has maximum penetration with maximum expansion, minimum meat damage, maximum temporary wound cavity.. AT ALL RANGES?
And if there is, CAN I ORDER SOME NOW....

regards

griff

Griff,

I was talking to a mate the other day about my caliber indecisions as per the other thread. I mentioned that a certain caliber I had thought of was no longer on the list due to its habbit of causing a lot of damage. His answer was

"well that will all depend on what you shoot through it and how fast you load it up..."


I like your idea!!!
All you need then is a is a laseer guided rifle to save you getting out of bed!!!



FB

Fallow Buck,
Your view is entirely correct in the light of:

quote:

"The usual connection between bullet speed and meat damage is entirely correct when applied to jacketed lead bullets. The faster you push them, the more they break up on impact and the more meat damage can be expected."

But there is also this to consider:

quote:

"Simply increasing the velocity with a bullet that does not fragment, will result in so little extra meat damage, that it can be ignored."

The point is that monometal bullets do not fragment to the extent that jacketed lead bullets do. The result is more usable meat on the carcass. We did a test with the same monometal 40gr bullet by using it in a 223 (3800fps) a 22-250 (4200fps) and a 220 Swift (4400fps). Once the carcasses were skinned and hung overnight, it was very difficult to tell which animal was shot with which calibre.

Griff,
What would you say to a bullet that, in game, will expand from as low as 1500fps and, at impact speeds of 4500fps, still retain 84% weight?

Very interesting subject,

Savage99 link is well worth a view, but not before bedtime!

Am realy interested in the effects of these monometal bullets, ultimately for their lack or talked of lack of meat damage, do they not just penetrate straight through lighter species, eg muntjac and roe?

I can remember shooting roe and red deer with a heavily constructed bullet (roe .243, red .270 - cannot for the life of me remember weights or bullet type, days before I got interested in reloading!)in a fatal broadside chest position, the animals showed very little signs of reaction, I shot them again, in the case of the red 3 times before it went down (witnessed by a Scottish hill stalker, of some experience). Both animals had little meat damage, small exit wounds but an unsatisfactory reaction to the shot.

Its getting that balance right, in another post I stated I am on a quest for the 'ultimate 7-08' bullet for all deer species with little meat damage, any more suggestions?

Griff, I am second in line when you find the requirements you stated in your reply!

nightwalker uk,
Muntjac seems similar in size to Steenbuck we have here, while Roe are similar to our Duiker. When using monometal bullets on such small species, calibres like .222, .223 and 22-250 are more than adequate and will produce one shot knockdowns every time, if shot through the lower half of the chest cavity. We place shots to deliberately avoid breaking shoulders unless it is absolutely unavoidable. In such a case, the better option is to break the far shoulder to minimise bone fragment damage.

Have a look at this for your 7-08.

I’ll join this one a little late if I may; there seems to be some argument here that is, to me at least, counter-intuitive.

As far as I can tell, the US research paper referred to is addressing the ‘debride lots’ versus ‘debride little’ argument……rather than mechanisms of incapacitation.

I suspect that the author’s premise is based on the fact that the mass of wound treatment techniques developed in the ‘high-velocity age’ (particularly WWs 1 & 2) were developed before the use of antibiotics was widespread….at a time when a surgeon would err on the side of caution in terms of debridement (because if he got it wrong there was no antibiotic ‘2nd chance’).

…do all combat medics agree with his theories? …I have no idea; but I would suspect there are opposing theories / practices that have not been presented.


In terms of ‘incapacitation’ rather than death at the cellular level; I find some of the statements made entirely counter-intuitive…….the ‘rate of wounding’ is being entirely ignored….(ie the size / rate of expansion of the temporary wound channel and the resultant impulse/ damage to surrounding organs).


…….if I were to make an indentation in your belly area by pushing a baseball slowly to make a temporary 2 or 3 inch indentation, the result would be discomfort. …however, if the baseball could be introduced to the same depth at 3000fps the result….in terms of incapacitation –and probably internal organ damage ….would be quite different.

quote:

What has also been shown is that if you take an absolute non frangible, non expanding projectile and you fire it at varying velocity into tissue with primary viscous visco-elastic property and the projectiles do not become unstable the permanent wound channels are exactly the same diameter irrespective of velocity. The temporary wound channels would differ in size.

….yes, but I’m not clear why –in terms of incapacitation- that the velocity related ‘rate of wounding’ (ie the size/rate of the temporary cavitation) is being considered irrelevant.

…... [ whilst I accept that the ‘spongier’ tissues such as lung do not have a “primary viscous visco-elastic†property and the effects of the velocity related ‘rate of wounding’ (ie the size/rate of the temporary cavitation) will be mitigated to some extent] however, when we are looking at the more 'watery' organs; a projectile (as described in the quote) at 200fps through filled milk carton will have a markedly different effect to the same proj at 3000fps.

….or have I entirely missed the point?!!

quote:

Originally posted by Gerard:
nightwalker uk,
Muntjac seems similar in size to Steenbuck we have here, while Roe are similar to our Duiker. When using monometal bullets on such small species, calibres like .222, .223 and 22-250 are more than adequate and will produce one shot knockdowns every time, if shot through the lower half of the chest cavity. We place shots to deliberately avoid breaking shoulders unless it is absolutely unavoidable. In such a case, the better option is to break the far shoulder to minimise bone fragment damage.

Gerard,

You will find that the Duiker are about the size of a muntjac, and Roe are the size of Bushbuck.

FB

Thanks FB,
I have never done a comparison and found the following from a variety of sources. It seems that deer are mostly heavier for height than antelope but the comparisons are interesting.

Steenbok
SIZE: Shoulder height 52 cm, mass 11 kg.

Muntjac
A mature animal may reach a height of 43-46 cm at the shoulder and weigh between 11 and 16 kg, the females (does) being slightly smaller.

Common Duiker
Average Mass: 15 kg (33 lb) Average Shoulder Height: 63 cm (25")

Roe
European Roe stand between 60-75 cm at the shoulder with bucks weighing between 24 and 30 kg, whilst the does are 2-6 kg lighter.

South African Bushbuck
SIZE: Shoulder height (m) 80 cm, (f) 70 cm; mass (m) 45 kg, (f) 30 kg.

Springbok
SIZE: Shoulder height 75 cm, mass (m) 41 kg, (f) 37 kg.

Blesbok
SIZE: Shoulder height (m) 95 cm, (f) 90 cm, mass (m) 70 kg, (f) 61 kg.

Red Deer
Amongst adults, the size of mature hinds can vary between 42-54cm at the shoulder and they can weigh between 57–115kg (125–250lbs). Stag weights vary between 90–190kg (200–420lbs)