[Greg1911]

are the hydro's meant to stop in the attacker or blow right through, because wouldn't it be Ideal if the round went in, expanded and finally exited the body that way it would be 2 holes instead of one.

[This message has been edited by Greg1911 (edited 12-04-2001).]

 

[BOLANTEJ]

uh.....

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Nothing like the smell of Breakfree to make my day complete.

 

[dsonyay]

Hmmm, interesting.

I think you should go to the libray and check out the book "Handgun Stopping Power" by Sanow and Marshall. They go into a great deal of detail about just how the energy should be directed. They seem to verify that Hydrashocks are well suited to do the job. Lot's of autopsie results and real world shooting studies. Plus they talk a lot about the famed "goat shootings"

Take care,
david

 

[Double Naught Spy]

HydrAshoks are like other hollowpoints. They are supposed to expand and transfer all their energy within the body, or that is the goal. I can't argue with the math, but the understanding of ballistics seems a little off.

 

[jpwright]

Except for one thing, Greg1911, your idea is on the right track. The ideal situation would be for the bullet to exit ... and drop to the ground, all energy expended. But there is a problem.

The problem is live skin. It's hard for a bullet to punch through living skin on exit. On entrance, the skin is held more or less in place by flesh underpinned by bone. On exit, the skin can and does stretch outward. It functions a lot like the net on an aircraft carrier, and a great many bullets are found under the opposite-side skin of the target for that reason.

What this means is that, in order for a bullet to exit, it has to have considerable velocity and energy left on the far side of the target. And that is energy not expended where it's needed.


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If God didn't want us to own guns, why did He make the 1911?

 

[A Johnston]

Originally posted by DHMeieio:
It might seem so, but from everything I've read the trick seems to be to get the bullet to expend its energy damaging internal flesh rather than making an exit hole. Plus, a bullet that exits its intended target now is free to hit unintended targets.

If making an exit wound is your goal, just use FMJ ball cartridges, they are reported to do it about 70% of the time.

An expanding (JHP) handgun bullet expending any energy into the target may have been an afterthought more than a design aspect. The amount of energy in a JHP and an FMJ are equal as long as the projectiles have the same grain weight and are traveling at the same velocity. I don't believe the expansion of a JHP, fired from a handgun, by it self necessarily equates into more energy transfer. In addition, the amount of energy expelled on to a target is generally less than 10% of the total amount of energy produced at the muzzle. Combine that with the durability and elasticity of the human body (with the exception of organs such as the brain, liver, etc.) and whatever energy is transferred from a handgun bullet to a human target becomes largely inconsequential. Handgun bullets simply aren't powerful enough to produce the kind of wounding (through the transfer of energy) that rifle bullets possess, no matter what the bullet design. The biggest benefit of a JHP is it's potential to expand and create a larger permanent wound cavity. Although FMJs might have more of a propensity to over penetrate I don't believe they pass through 70% of the time. Too much depends of the specific target and shooting circumstances.

 

[Double Naught Spy]

A Johnston, you are correct, in part, that part being a lack of explanation on my part. More energy is transferred from the hollowpoint IF it does not exit and the JHP does. For a round that passes through, it takes energy with it. That is energy not being absorbed by the tissues. The benefit of the energy is not in that it is absorbed, but that it causes damage to the tissue absorbing it.

Something a lot of people do not realize is that as most expanding bullets expand, their potential for penetration is lessened. With only a non-replentishable amount of energy present on entry into the body, any feature or event that slows the projectile will cause a loss of energy, hence shallower penetration for expanded rounds. The idea is that part of the energy that would go to over penetration of a FMJ round is used in the expansion, hence the hollowpoint may not penetrate as deeply, it is supposed to make a larger wound for the distance it does penetrate. Keep in mind that through and through wounds often go through muscle as the first and last major organ system (not including skin). Muscle damage, outside of the heart or diaphram, may be totally inconsequential. Thus, you want the round to penetrate the muscle, enter the organ cavity, and then be increasing in size to do lots of damage. Muscles do a much better job of handling damage than organs.

In essence, all the energy gets kept in the body cavity. Of course there are problems. Some hollowpoint rounds hit hard objects such as bone, expand, and then fail to penetrate deeply because much of their energy was expended trying to penetrate the bone as an expanding object.

While the concept of two holes sounds really good, many through and through wounds do little or no significant damage. Yes, it hurt. Yes, the guy bleeds. Yes, he may die from it, but it may be some time later. Through and through wounds often have a narrow wound channel and therefore may not do as much damage. Plus, muscle gets penetrated twice with neither event doing much harm.

 

[A Johnston]

DNS - I basically agree. A bullet needs to be big, penetrate deeply, and tear up vital organs. My only point was that energy, in handgun bullets, is largely overrated. The bullets themselves not possessing enough energy to wound through the transfer of said energy no matter what bullet design. And in the cases where a massive amount of energy is generated a frangible or expanding bullet design usually breaks up and/or does not penetrate enough due to the high velocity and/or low grain weight.

 

[A Johnston]

Originally posted by DHMeieio:
If you have two bullets of equal mass, fired at equal muzzle velocities from guns an equal distance from their target, it is a fact that the bullet that passes through the target will transfer less energy--i.e., cause less damage--than the bullet that expands and stops within the target.

You are correct about the way energy is transferred (FMJ vs. JHP), I overlooked that. However, I have to restate the difference in wounding (between FMJ and JHP) caused by the transfer of energy is nominal. As neither bullet design, fired from a handgun, possesses enough power to cause significant damage due to energy.

 

[ShootinSpirit]

Ever see the Gelatin blocks used to test ammo. The bubble that marks the bullet path is considerably larger than the bullet itself. Especially for hollowpoints. This large bubble is caused by hydrostatic shock. ie the energy acting on the gelatin pushing forward is greater than the static force (the force that allows the gelatin to hold its own shape) of the standing gelatin. This causes rupturing. Since soft tissue is very similar to 10% Gelatin the theory is that the same damage would occur.

While handgun pressures are nowhere near that of rifles its a heck of a lot harder than a punch. People whereing body armor have had life threatening injuries from the blunt trauma of their vest catching a bullet. Many modern vests have a pocket for a titanium or ceramic "trauma plate". This is so that the energy of a bullet caught near the heart is transfered over a wider area and not deep into the body where it can cause serious damage.

For you physics lovers:
.45 caliber low-medium velocity
Force=mass x velocity (230gr x 830fps)
Preassure=Force/area (Force/inches)
230 grains = .03286 pounds

Blunt trauma:
force = 27.2738 pounds
pressure = 60.6 pounds per square inch (psi)

Still think handgun energy is nominal?

Just for fun, the effectiveness of a 3x5 trauma plate:
force = 27.2738 pounds
pressure = 1.818 pounds per square inch (psi)

 

[A Johnston]

Originally posted by ShootinSpirit:
Still think handgun energy is nominal?

Yes I do. A JHP may transfer energy more efficiently (as evidenced by gelatin block tests) than an FMJ and create a seemingly larger temporary wound channel in gelatin blocks. However, the real issue here is weather a JHP causes more actual damage, through the transfer of energy, than an FMJ. JHPs transfer energy differently than FMJs. What needs to be recognized is that temporary wound channels produced by handgun ammunition are of little consequence. Understanding this involves understanding exactly what a temporary wound channel is. When a bullet enters a human body it causes the tissue surrounding the bullets path to flex away from the bullet, but after the tissue flexes away it rebounds back to it's original position. The only thing that is left is a permanent wound channel. This flexing of the tissue is what referred to as a "temporary wound channel". Regarding high velocity rifle cartridges, this flexing occurs so violently and with so much force that the tissue flexed actually tears and damages. However, pistol cartridges travel at much slower velocities and so the flexing of tissue (the temporary wound channel) does not occur violently enough to actually tear and damage tissue. When the bullet passes through the body the tissue flexes out of the way and the rebounds back to its original shape undamaged and largely unaffected. The reason why JHPs perform so impressively in gelatin blocks is due to the gelatin blocks differing from actual human tissue. The gelatin block doesn't have the elasticity required to rebound from temporary wounding due to energy transfer. So although an impressive temporary wound channel is formed (due to the transfer of energy) it is not a fair representation of what would actually occur in a human body. It is more of a guideline for how a bullet will expel its energy. The basic point is this; the energy expelled from handgun bullets does not cause actual wounding or damage. This is an excerpt from the U.S. Department of Justice Handgun Wounding Factors and Effectiveness study;

Frequently, forensic pathologists cannot distinguish the wound track caused by a hollow point bullet (large temporary cavity) from that caused by a solid bullet (very small temporary cavity). There may be no physical difference in the wounds. If there is no fragmentation, remote damage due to temporary cavitation may be minor even with high velocity rifle projectiles. Even those who have espoused the significance of temporary cavity agree that it is not a factor in handgun wounds:
"In the case of low-velocity missiles, e.g., pistol bullets, the bullet produces a direct path of destruction with very little lateral extension within the surrounding tissues. Only a small temporary cavity is produced. To cause significant injuries to a structure, a pistol bullet must strike that structure directly. The amount of kinetic energy lost in tissue by a pistol bullet is insufficient to cause remote injuries produced by a high velocity rifle bullet."
The reason is that most tissue in the human target is elastic in nature. Muscle, blood vessels, lung, bowels, all are capable of substantial stretching with minimal damage. Studies have shown that the outward velocity of the tissues in which the temporary cavity forms is no more than one tenth of the velocity of the projectile. This is well within the elasticity limits of tissue such as muscle, blood vessels, and lungs, Only inelastic tissue like liver, or the extremely fragile tissues of the brain, would show significant damage due to temporary cavitation.
The tissue disruption caused by a handgun bullet is limited to two mechanisms. The first, or crush mechanism is the hole the bullet makes passing through the tissue. The second, or stretch mechanism is the temporary cavity formed by the tissues being driven outward in a radial direction away from the path of the bullet. Of the two, the crush mechanism, the result of penetration and permanent cavity, is the only handgun wounding mechanism which damages tissue. To cause significant injuries to a structure within the body using a handgun, the bullet must penetrate the structure. Temporary cavity has no reliable wounding effect in elastic body tissues. Temporary cavitation is nothing more than a stretch of the tissues, generally no larger than 10 times the bullet diameter (in handgun calibers), and elastic tissues sustain little, if any, residual damage.

 

[DBR]

There seems to be a difference between "permanent tissue damage" and "stopping power" at the enemic energy levels of handgun cartridges. Remember, energy is the ability to do work. If a bullet expends all of its energy in a body it has done more work on the body than an identical bullet that exits. There is some fairly strong evidence that above a certain energy threshold level, the temporary stretch cavity may induce other bodily reactions which can shut down essential neurological functions (at least temporarily) and cause a rapid collapse.

When you get to velocities that are significantly greater than supersonic - like MKII (approx 2200fps) then the sonic shock wave also causes a large expansion of the wound channel.

 

[LAK]

Talking of physics; the human body does really not offer the physical resistance neccessary for so-called "energy transfer". That is to say; unless a major bone (brain, spine, pelvis), the aorta, or the heart (when it is full of blood), for examples are struck - bullets tend to just zip on through. JHP's, if they expand, might tend to produce a larger diameter permanent crush cavity, but unless penetration is deep they still may not produce an overall greater permanent wound cavity (or loss of blood pressure) than a FMJ, or other bullet, that penetrates through and exits. Rifle bullets, at rifle velocities are another matter, but even rifle bullets can often fail to effectively "transfer" much energy - especially in the aerated lung tissue.

 

[ShootinSpirit]

AJohnson -- very interesting information on the "temporary wound channel" and the resilience of human tissue. Even if the "permanent wound channel" is not enlarged by the energy transfer I still feel that the shock induced by the "temporary wound channel" is true stopping power as evidenced by LEs who've been shot while wearing a vest. no bullet cavity, but still shock from the blunt force trauma.

The trauma caused by the energy transfer may not cause any severe rupture according to the information you shared in your last post, but it would still cause bruising, and more importantly shock. (This is what I think DBR was speaking of.)

Shock has been known to cause death, but more importantly it causes an immediate degree of low Bp, irregular breathing, disorientation, loss of muscle control, etc., which could contribute to stopping an assailant. I'm not sure if any research has been done in this area with regard to gun shot wounds, but shock is considered a medically critical condition.

LAK -- energy is transfered when the motion of one object is slowed or stopped by another. In effect, the energy that moved the bullet forward is transferd to the body that catches it. If the bullet exits it is not because there was no energy transfer, but because there was surplus energy. In some cases the transfer could be nominal, but my guess is that most rifle bullets transfer a significant amount of energy, especially with good HPs. However, on that note you bring up some interesting questions about rifle bullets.

My experience with rifles is limited, but could their be a greater energy transfer if the bullets were slower? At what point would this cause a greater permanent wound cavity? Does a .223 caliber from a rifle produce a greater wound cavity than say a .45 ACP? Hunters may have some good imperical evidence on this so I'm gonna start a thread in General Gun Disscussion.

 

[USMA Pistol]

Here is a link to the Mechanics of Handgun Wounding article from DoJ:

http://www.pistolsmith.com/viewtopic.php?topic=1866&forum=24

This should answer most questions about handgun/rifle caliber effectiveness and energy transfer. Most rifle calibers will produce far greater damage to the human body than a pistol caliber due to the fact that they are travelling at such high veloctiies when they impact the body (compared to a pistol round fired at the same distance). The higher velocity = larger temporary wound channel, and a more violent ripping of soft tissue. If you take 55-gr. M193 FMJ 5.56mm, for example, a larger permanent wound channel would be created at closer ranges because the round violently fragments after penetrating and yawing inside the human body (this assumes the round did not hit a bone). Such violent fragmentation is rarely seen in pistol cartridges (if ever) because they travel so much slower than a rifle round. Most pistol rounds travel anywhere between 800-1500 fps, whereas most rifle rounds travel at 2000-3000+ fps.

Bottom line: for sheer energy transfer, light, fast bullets excel. For larger permanent wound channels, heavier bullets are king.

I prefer fast AND heavy.

 

[P. Greene]

In my humble opinion, all of the posted information is essentially correct. I do feel however, that there is some hairsplitting going on.

To me, the shooting of an assailant in a legitimate self defense situation, consists of two objectives ;

Stopping the attack mounted by the assailant (stopping or "knock down" power) and killing him.

As is made abundantly clear by the info. set forth in previous posts, the matter of energy transfer is well understood here. (projectile mass x velocity, etc.)

What seems a bit more murky to me, is the concept of wounding.

The idea here is to cause as much immediate blood loss and organ damage as possible. To this end, the advantage of a hollow point over a fmj is the potential expansion of the projectile.

An expanded projectile becomes larger and probably a bit less smooth. This has the effect of causing greater tissue damage via greater contact area, more tearing of tissue and a larger wound channel into which the assailant will bleed.

Hollow organs such as the kidney, lungs, intestines and of course, the heart, bleed much more readily than do solid organs such as the liver and spleen for example.
The description of the "temporary" wound channel rendered in a previous post, is dead on.
A bullet wound to the liver in particular, (a solid organ) will likely prove fatal without prompt, surgical intervention. This is the result of massive hemmorhage due to the large amount of blood supplied to that organ .
This will probably take a while however. The initial, "temporary" wound channel will close and leave a wound which roughly corresponds to the circumference of the projectile. The elastic properties of human tissue will allow the initial wound to close and, to an extent, apply an amount of pressure to the damaged tissue, slowing the rate of bleeding. This is called "tamponade".

Rather than go on and bore you with the blathering of info. that you probably know as well as I do, let me simply say that the ideal defensive bullet wound is the result (my opinion) of maximum energy transfer, bullet circumference and shot placement.

 

[mohecus]

wow guys! what if all of you were shot with
a 45acp of your own desired configuration
from a set distance and impacting the same
point of your anatomy and then you all talked
about who had the bigger wound channel and all. ha ha ha. i think by the end of that
talk someone might think a 45acp is dangerous. ha ha. im sorry it was just a
little thick on mechanics and ended up
sounding like everyone thought a pistol
bullet was not to painful. so just ignor me.
ha ahaa ha .!! i love this forum.

 

[P. Greene]

Mo',

You're right. It's easy to get sucked into this physics thing and wind up somewhere out in the weeds. I do think that you have an idea however.

Volunteers?

 

[tex_n_cal]

Lots of theory above, and indeed, all good points. Now here's a little different take on things...

In the world of actual defensive shootings the pistol ammo with the greatest percentages of one-shot stops seem to be the fast movers, with quick expanding hollowpoints. Examples are the 115gr 9mm+P+ or 125 gr .357 mag.

In the hunting world, all the "experts" advocate non-expanding blunt nosed hard cast bullets(at least for revolvers), that are intended to shoot through whatever animal you're hunting.

I sure wonder how two completely different schools of thought emerged in this regard.

Could it be, that one reason the quick expanders are so effective is because they have a loud muzzle blast? That a bullet expanding and stopping inside HURTS?

Maybe pain and the deafening noise gives a psychological advantage to this ammo? The thinking animal (even if a stupid criminal) called man is more likely to cease aggression due to greater pain stimulus?

What do I keep for defense? Obviously, a .45 loaded with Hydra-shoks - also good percentage of one-shot stops, and the big hole in the muzzle tends to make bad guys turn & run so I don't have to shoot them in the first place! My theory, anyway

 

[USMA Pistol]

Mohecus, definitely didn't want to make it sound like .45 ACP Hydra-shoks aren't gonna hurt! Thank God I don't know from first hand experience, but I imagine it's a tad bit worse than getting a skinned knee...hmm...

The points about the physics of the bullet are important, however. A .45 caliber round, shot into the human body in an appropriate area, can likely cause incapacitation (a nice euphamism for death), but of course the question is: how quickly? Shot placement largely determines how quickly a BG will be incapacitated-- central nervous system (CNS) hits to the brain or spine are the quickest stoppers (just about instantaneous), and shots to center of mass (COM) are aimed at 'rapid exsanguination' or 'hypovolemic shock' (also known as bleeding to death quickly). After shot placement, the next most important element in incapacitation is how much tissue is destroyed and damaged, which is measured in terms of permanent wound channel and temporary cavitation (temporary cavitation with pistol rounds is usually negligible). This is where the hollowpoint v. full metal jacket debate enters (expansion vs. penetration). In general, expansion is preferred, especially since a good defensive hollowpoint round should provide good penetration anyways. Another measure of tissue destruction/damage is energy transfer, which is more in the realm of physics to me than the realm of wound ballistics, but it makes some people happy that this bullet carries 500 ft.-lbs. of energy instead of 450 ft.-lbs. of energy. Lastly, I might consider psychological factors (i.e., muzzle blast, realizing one has just been shot, presumptions on what is expected when one is shot) as a factor of incapacitation, but assuredly not a reliable one.

I guess the bottom line is that .45 Hydra-shoks are gonna make big ugly holes (unless the BG is wearing a ballistic vest), no matter where he/she gets shot, but the importance in selecting a defensive round is how quickly the round will stop the BG or how badly it will damage him. The difference between life and death in many cases is measured in inches or less. Remember: the bullet that Hinckley shot at Reagan was mere millimeters from his heart, Reagan was sure lucky to have survived...thank God Ronny was a tough ol' bastard...

In any event, I've rambled and written a damn dissertation here, most of what I have mentioned has been addressed a dozen different times on this forum as well as others. If penetration is the issue, go with hardball 230-gr. .45. If it's expansion you need, then go with Hydrashok, Gold-Dots, Black Talons, or whatever JHP feeds most reliably in your gun. Doesn't make much difference in a life-or-death situation whether or not a bullet penetrates both sides of the BG's body, what matters is where in that BG's body the bullet is placed.

I think the even better question is: is it better to use a round that has less felt recoil and less muzzle flip (like a 9mm, or .357SIG) that can put more rounds on target faster, or a heavier round (.45ACP, 10mm) that puts bigger holes in an assailant at the cost of bigger recoil?