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September 25, 2012, 11:38 PM | #76 | |
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September 26, 2012, 12:05 AM | #77 | |||
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And it is more precisely stated by Duncan McPherson (as quoted by 481 in post 67):
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September 26, 2012, 12:06 AM | #78 | ||
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It's one thing to say that kinetic energy/temporary cavity are not a reliable wounding mechanisms in handgun terminal ballistics, it's another entirely to take the next step and say that they do not wound. The former is debatable and dependent upon the energy levels and types of tissue involved. The latter is demonstrably false. Temporary cavity, which is accepted to be directly related to energy, CAN wound, it just hasn't been shown to wound reliably at the energy levels commonly encountered in self-defense handguns. At typical handgun levels, to date, it has only been demonstrated that it can cause significant wounding if inelastic tissues are involved, but in those cases it can not only cause wounding, it can cause catastrophic wounding. As far as his statement that kinetic energy does not wound, that's simply nonsensical from a scientific standpoint. Kinetic energy is the potential of a moving projectile to do work. Damage to the target medium is, at least to some extent, related to the work done on the target medium by the projectile and therefore is, in some way (which may be very complex and difficult to determine) related to the kinetic energy. I don't have enough context from MacPherson's quote to know exactly what point he was trying to make. It is certainly true, as has been stated by others, that attempting to fully analyze the terminal ballistics problem using only kinetic energy (or any other single parameter) is impossible due to the complexity of the problem, however, that is not sufficient justification to completely dismiss kinetic energy as a factor in the overall problem. Just to be clear, I'm not claiming that kinetic energy is the most important factor in ballistics--not by any means. I'm just saying that the fact that it's not the most important factor, or the fact that it can't/doesn't tell the whole story doesn't change the fact that it is certainly part of understanding terminal ballistics and that it provides useful insight into the problem.
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September 26, 2012, 12:18 AM | #79 |
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LOL well played sir!
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September 26, 2012, 01:03 AM | #80 | |
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We so often see the passionate claims that cartridge A is superior to cartridge B because it has 500 ft-lbs of energy at the muzzle compared with the meager 450 ft-lbs of cartridge B. To be sure, a projectile that is moving had kinetic energy. And a bullet to effectively penetrate must have some minimum level of kinetic energy. But factors such as sectional density of the bullet, momentum and diameter/expansion of the the bullet and thus the permanent wound cavity are more useful and relevant to trying to predict terminal performance, at least at typical handgun velocities.
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September 26, 2012, 01:35 AM | #81 | |
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Take a ping pong paddle and a ping pong ball and hit a guy in the head with the hardest serve you can manage. Then take a golf club (the driver) and a golf ball and hit that same guy in the head with the best drive you can manage. Note the different effects on the target. Neither the ping pong ball nor the golf ball will cause a permanent wound channel. And neither one will give any penetration. And neither one will destroy tissue in its path. But the golf ball could kill the guy. Why? The golf ball delivers much much greater energy to the guy's head. Energy delivered to the target matters. If you don't believe me, you provide the test head and I'll provide the ping pong ball and the golf ball. |
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September 26, 2012, 01:43 AM | #82 | |
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September 26, 2012, 03:44 AM | #83 | |||
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Kinetic energy is helpful in understanding terminal ballistics and handgun cartridge effectiveness. It does not, by any means, tell the entire story, and one can certainly be led astray by becoming obsessed with it or by giving it too much consideration when comparing cartridges. However, science does not allow us to discard it, nor is it wise to discount it too much given the obvious correlation between energy, work and damage. Quote:
One very simple example--the list provided as being more useful than energy includes expansion. However, expansion is more closely related to energy than any of the other listed parameters since it is evidence of work done on the projectile and that work is a function of impact energy. Ultimately, energy plays at least some part in nearly every aspect of terminal ballistics--an important part in some respects and under certain circumstances and perhaps a trivial part in other respects and under another set of circumstances. A list of the "ABCs" of terminal ballistics is just as incomplete without kinetic energy as it would be if one excluded momentum or velocity, and it's not possible to fully understand the topic without understanding how it's affected by kinetic energy. I'm not saying anyone does fully understand the topic--I'm just saying that kinetic energy is one of the basic building blocks of terminal ballistics and any house built without it is incomplete. Quote:
The reason both statements are true is that a wound from a high velocity projectile incorporates aspects of both penetrating wounds and blunt force trauma. In fact, temporary wound cavity is an excellent analog for blunt force trauma. If one is hit in an area containing or composed of brittle or inelastic tissue, it can be catastrophic. If one is hit in an area that is largely made up of elastic tissue, there may be little effect other than pain. If one completely ignores kinetic energy and temporary cavity, one ignores one of the two main components of high velocity projectile injuries. It's certainly true that the circumstances of a particular situation may dramatically emphasize one of the two aspects over the other, but neither one is ever completely absent, except, perhaps, when effective body armor is involved and there is no penetration.
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September 26, 2012, 04:19 AM | #84 |
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#8 post
[QUOTEReliability, then accuracy, then adequate penetration, then shootability, and last expansion as I see it.
I like Federal HST standard pressure at the heaviest weight per caliber: 230 for .45, 180 for .40, and 147 for 9mm. All are subsonic, but all move at good velocity (850 .45, 1000 for .40, 990ish for 9mm). All get around 12-12.5" in gelatin, do well (for caliber) with barriers, and offer reliable expansion. ][/QUOTE] Good post, short and sweet. The reason I love the 9mm, rapid shots are possible, less recoil, you get a bunch of them! Glock19 has 16 ready to go. |
September 26, 2012, 05:34 AM | #85 | |
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Provided one teeny tiny litte detail.... I get to call the range...say,,200 yards? It's all relative & it's all the different pieces of the ballistic puzzle. Depsite having a lot of "muzzle energy" a foot or two away from the T. Downrange, that golf ball hasn't got enough left to resist being thrown off course by a blade of grass. OTOH - no way no how would I stand in front of a ping pong ball launched from some device that could toss it 6 or 7 thousand fps. Again - I keep going back to what I concluded... Velocity is the more critical figure I'd want to know. The energy will either be there or it won't. Velocity is also a much better indicator of how far downrange I can go & how flat the round will shoot. Energy figures don't really tell me that. |
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September 26, 2012, 06:50 AM | #86 | |
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The question in the original post did not ask if we consider velocity or bullet weight to be more important, it asked if we consider velocity or muzzle energy to be more important. Those two come from opposite sides of the equation. Muzzle energy, as has by now been thoroughly explored in this thread, is derived from the bullet weight and the square of the velocity. Those are the two variables, and the muzzle energy is the result -- the product of the equation. So the original question really asked if we are more concerned with one of the two input factors, or with the output. I am concerned with the output -- especially if one of the two input variables is unknown and is not part of the discussion. |
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September 26, 2012, 08:52 AM | #87 |
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AB, I counter thus:
Velocity's importance could be based not only on going fast enough (to yield effective energy, and desired range and flatness of trajectory), but also on not going too fast. Most firearms have a sweet spot in velocity for accuracy. Most projectiles have a velocity range below which, they will not expand, and above which, they fragment - potentially preventing penetration. (Alliteration free of charge.) So one could argue velocity is more important with regard to finding the ideal velocity for the particular firearm and bullet combo. That would be a completely separate argument than velocity, solely with regard to energy level. |
September 26, 2012, 08:56 AM | #88 | ||
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For that reason, the question asked by the OP, "In a defensive rd for a handgun which is more important to consider....muzzle velocity or muzzle energy?" is meaningless- even nonsensical- since velocity is a component of kinetic energy and momentum. As a result, the OP's question essentially amounts to asking, "In a defensive rd for a handgun which is more important to consider....muzzle energy or muzzle energy?" It seems that he had his answer before anyone posted.
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September 26, 2012, 09:03 AM | #89 | |
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Nice...
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September 26, 2012, 09:10 AM | #90 |
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.357 Mag or .44 Mag FMJ's always penetrate and most of the time, leave a hole all the way through. To me the projectile size and type makes more difference than velocity.
The only high velocity cartriges I really care about are varmint rounds because you need velocity for long range shots. |
September 26, 2012, 01:13 PM | #91 | |
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The sentence you quote from me in no way dismissed kinetic energy. But it seems you missed that and it may be because you tend to treat kinetic energy as a force distinct and apart from the moving bullet. Odd because you correctly say..."only moving projectiles can cause damage" which is correct and a point I made. It is the bullet that does the damage. The amount of kinetic energy that the bullet possesses is a factor in how much damage. tipoc |
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September 26, 2012, 01:28 PM | #92 |
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The temporary stretch cavity is a factor in wounding. Nerves, blood vessels, arteries, muscle tissue etc. are stretched and torn to one degree or another (based on a variety of factors) which do effect the severity of the wound.
Fackler and others bent the stick too far during the course of their debates, when they said the so called temporary cavity was not a factor. They were correct in insisting that the only thing that could be counted on though was the direct path the bullet took. Both the mass of the bullet and it's velocity and energy are factors. tipoc |
September 26, 2012, 02:04 PM | #93 | |
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September 26, 2012, 02:37 PM | #94 | ||
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Both are correct, which is why Fackler was ultimately run off from the FBI and the IWBA is now only a memory. They drank their own cool aid and manipulated data to suit their agenda, Dr Wolberg at San Diego was one of the obvious ones with the paper on the subsonic 147 grain 9mm. We hear so much about it because they are "doctors" and have published papers all over the errornet.
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September 26, 2012, 04:25 PM | #95 | |||
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Wolberg's research paper is valid, here's why- It is common and accepted practice for researchers to select the parametric and data constraints for their case studies. If this were viewed as reason to discredit his or anyone else's research and findings, then every case study research article that has ever been written and its findings would have to be thrown out. In fact, parametric and constraint selection is a sound practice within scientific research projects and to attempt to portray it as some sort of dishonesty is an act of intellectual dishonesty itself. So long as it is done honestly and openly (as evidenced by Wolberg's explanations of the constraints of his data selection on the first page of the article cited above) and the reasons for such constraint can be shown to be valid, then it is a valid practice. Wolberg does this on the first page (marked as page 10) of the article stating: Quote:
Wolberg states (also on the article's first page) that only shots that remained within the bodies of those being autopsied were considered for this correlative study: Quote:
Portraying Wolberg as being dishonest, when in fact he wasn't, as is demonstrated by the disclaimers described above, is intellectual dishonesty. Anyone wishing to read Wolberg's article for themselves- http://ammo.ar15.com/project/Fackler...hester_9mm.pdf -may do so and confirm for themselves the text that I have specifically quoted from the article and that it is presented clearly and plainly for anyone to see.
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QUANTITATIVE AMMUNITION SELECTION Last edited by 481; September 26, 2012 at 05:32 PM. |
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September 26, 2012, 07:14 PM | #96 |
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As I said before... Energy transfer from handguns does not cause enough cavitation to create permanent damage in tissue. This cavitation is expressed as the "temprorary" wound cavity. HP rounds do increase energy transfer, and cause a little more cavitation, but not significant amounts. The permanent wound channel is the same size or a little larger than the bullet as it passes through. Expanded HP do increase the size of this permanent wound channel.
This lack of cavitation damage excludes the more dense and inelastic tissues... but those tend to be vital organ tissue like the heart, liver and kidneys... All of which would cause massive bleeding and death when hit directly anyway, the extra damage created is a little less important in this situation. (the heart is of course quickest to death, followed by the liver then kidneys) What the energy transfer and temporary cavity do... is cause bruising and pain. So higher energy rounds will hurt more, but pain is not a guarantee of stopping the threat. Now rifle rounds... their higher energy and momentum create much more cavitation... This cavitation is actually more than the elasticity of the tissues can take, and it causes permanent damage. So you get a much larger permanent wound channel... HP increase this effect further... So this is why energy is more effective in rifles. Handguns can only rely on shot placement and adequate penetration to reach important structures. Momentum and weight aid in penetration. Handgun rounds all have the momentum to penetrate deep enough, but HP rounds cause energy and momentum loss, which means the rounds may not penetrate deep enough if the HP design causes expansion to quickly. This is why heavy for caliber rounds penetrate deeper and more consistently... the inherent inertia of the added bullet mass, plus the momentum of the bullet work together to create better penetration depth and consistency. Higher energy rounds do penetrate more, but without the added mass inertia, the performance of penetration depth is less consistent. Last edited by marine6680; September 26, 2012 at 07:26 PM. |
September 26, 2012, 07:29 PM | #97 | ||
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I never said accuracy fell under ballistics. I just said "to me, accuracy trumps 'em both" in reply to the question posed by the OP. Quote:
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September 26, 2012, 09:43 PM | #98 | |
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It is well-documented that it can cause permanent damage to inelastic tissue, and there is also evidence that, under certain circumstances, it can even cause permanent damage to elastic tissue. This article discusses injuries to arteries caused by temporary stretch. According to the article, these types of injuries can be found in patients with "gunshot wounds inflicted by handgun or rifle". http://www.ajol.info/index.php/sajs/...le/34334/24724
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September 27, 2012, 04:35 PM | #99 |
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If it isn't reliable... then it can't be relied on nor counted. Would you consider ammo that has a 1% failure rate reliable enough for defense work? Then why credit extra damage that is low reliability...
Internal hemorrhaging in tissue is bruising... its only a serious problem in a open cavity or if its outside the body. Its also not a major issue if the damage is to smaller arteries. At least not with the speed needed in a defense situation. |
September 27, 2012, 10:33 PM | #100 | |
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Now accelerate both to the exact same velocity and let each one impact your test medium of choice: ballistic gelatin, wet newsprint, hog carcass, your mother-in-law ... whatever you choose. I respectfully submit that the second projectile -- the one filled with a core made up of weightless Unobtanium -- will not expand nearly as reliably as the standard Golden Saber projectile. Why? Because it requires energy to expand metal, and both lead and copper are metals. It is hydrostatic pressure of the impacted medium that presses into the cavity to force the bullet to expand, but the impact medium is static. It has no kinetic energy, so where does the energy come from? It comes from the energy -- the momentum -- of the projectile. Yes, it requires velocity, but it also requires mass -- and the question posed at the start of this discussion ignored mass. ALL we were asked about was velocity or energy. Projectile number two in my hypothetical experiment will have FAR less energy than the standard bullet, at the same velocity. When those are the only two options, the only valid choice is energy. |
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