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Which is more important in ballistics?

Discussion in 'Handguns: General Discussion' started by IMTHDUKE, Sep 22, 2012.

  1. Kleanbore

    Kleanbore Moderator

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    The question asked was, "In a defensive rd for a handgun which is more important to consider....muzzle velocity or muzzle energy?"

    At first glance, that seems nonsensical. Energy is a function of velocity and mass. But the discussion has flushed out more. Perhaps this will summarize things well enough:

    • In handgun bullets, energy is not an imprtant factor in determining wounding effectiveness.
    • The important factors are the following:

    1. Where the bullets hit, and in what direction, in a 3D human target
    2. Penetration
    3. Bullet diameter

    The first one does not refer to bullseye accuracy; the target is likely to me moving fast, and the defender will not have time to aim accurately, or to reliably make one shot hit where he or she would like, and rapid repeat fire is likely to be needed.

    Penetration into a given medium is a function of velocity, mass, diameter, bullet shape, and bullet construction. It can be measured by firing into surrogate materials that are generally representative of human targets. Predicting the results of that kind of tests using the results of penetration in water has been done.

    There is not a lot of difference between the diameter of an expanded .45 bullet and that of an expanded 9MM bullet. A .45 will generally have a lower magazine capacity and, in a firearm of similar size and weight, greater recoil, which will make rapid repeat shots more difficult.

    It hasn't been discussed much in this thread, but some may not realize that boom, blast, and fuss at the muzzle does not translate into "knockdown power." There's really no such thing.

    There is insufficient information available, and there are far too many variables involved, for anyone to draw any meaningful conclusions from the results of real-world shooting incidents.

    Personally, I do not see the point in spending much time trying to decide whether the modeled or tested performance of one particular round is marginally better than that of another. Given reasonable published assurances that all of my choices meet minimum standards (I'm happy with FBI standards), I will base my choices on reliability in my handgun, availability, and price, in that order.
     
  2. 481

    481 Senior Member

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    CD, You can read for yourself here-

    http://quantitativeammunitionselection.com/the_book

    copied/pasted from various parts of the website-

    QUANTITATIVE AMMUNITION SELECTION presents a mathematical model that allows armed professionals and lawfully-armed citizens to evaluate the terminal ballistic performance of self-defense ammunition using water as a valid ballistic test medium. Based upon a modified fluid dynamics equation that correlates highly (r = +0.94) to more than 700 points of manufacturer- and laboratory-test data, the quantitative model allows the use of water to generate terminal ballistic test results equivalent to those obtained in calibrated ten percent ordnance gelatin. The quantitative model accurately predicts the permanent wound cavity volume and mass, terminal penetration depth, and exit velocity of handgun projectiles as these phenomena would occur in calibrated ten percent ordnance gelatin and soft tissue. With a confidence level of 95%, the model predicts the terminal penetration depth of projectiles in calibrated ordnance gelatin within a margin of error of one centimeter.

    The book sure was a learning experience for me. :)
     
    Last edited: Sep 27, 2012
  3. 481

    481 Senior Member

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    Great post.

    Well, Kb, I'll say this- you and I agree about as completely as two folks can about the vast majority this stuff. I doubt that there is any significant difference between our points of view- even if you were messin' with me for a bit! :D
     
  4. brickeyee

    brickeyee Senior Member

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    Then you have a very limited understanding of physics.

    Billiard balls are nearly 100% elastic collisions.
    VERY little energy is lost.

    A punching bag is at the opposite end, an almost 100% elastic collision.
    The bag deforms absorbing the energy.

    Human tissue is not exactly a liquid very amenable to simple fluid dynamics analysis in many cases.
    It is NOT isotropic (uniform) in composition, strength, density, or much of anything else.
    The fact that cells have a high concentration of water does not remove the other components that give them shape and form.

    There is a reason we do not look like jellyfish.
     
  5. Kleanbore

    Kleanbore Moderator

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    ^^^

    Good answer.

    McPherson points out the complexity associated with the conversion of kinetic energy to thermal energy in what he calls "real" collisions. The real collisions were not fluid dynamics events.

    But: and it hadn't occurred to me, by firing into water, he was able to greatly simplify things by using a virtually pure momentum transfer experiment in which energy transfer was insignificant. Correlation with (gelatin representatives of) real collisions was the next trick.

    By the way, I never realized that it was an interview with McPherson I was watching when he set the record straight for those who had concluded from the movement of a target's head (through which the bullet had passed) that they could prove the direction from which the shot had come.
     
  6. 481

    481 Senior Member

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    Ya see, when you say stuff like this, it makes me think that you'd enjoy reading books like MacPherson's Bullet Penetration and Schwartz's Quantitative Ammunition Selection.
     
  7. Skribs

    Skribs Senior Member

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    Bullet design will affect greatly how much energy you need. Essentially, you want to make a hole 12-18" deep and have it go as wide as possible. Handgun rounds aren't going to have enough energy to create the kind of permanent cavitation you'll see from rifle rounds.
     
  8. 2zulu1

    2zulu1 Senior Member

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    You're correct, I have a very limited knowledge of physics; but, I can accurately calculate bullet penetration in soft tissue based upon data obtained from a bullet captured in water.

    Perhaps you can share with us your bullet penetration calculations based upon punching a billiard ball.
    :)
     
  9. MCgunner

    MCgunner Senior Member

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    Velocity really doesn't matter, only in the energy equation. It is energy that matters and at 500 fps + or -, the ballistic pressure wave matters. No, it's not a "reliable mechanism" if the shot isn't accurate in the proximity of a major nerve network, but I've seen the results and seen actuall remote tissue damage from a bullet's pressure wave NOT involving nerve tissue, even from a 165 grain Keith style SWC fired at 1800 fps making around 1200 ft lbs ME. Animal was 80 yards down range, so energy was in the 700 ft lb range with velocity down to around 1400 fps near abouts. Ths was a lung shot behind the shoulder on a 110 lb whitetail doe that jumped upon being shot and went about 20 yards before piling up. Around 2-3 seconds max, maybe less, not more, from hit to death with a lung hit, no other vitals, just the lung.

    That's just one instance. I've seen lots more from calibers like 9x19 +P on trapped hogs, enough to make me a believer in the 9mm as a self defense caliber. I like the confidence in having used the gun on something over and over and seeing the results.

    But, you can't shoot something in the foot and expect it to be immediately lethal. You still must put the shot in the right place. Whatever mechanism works is the one I'll run with. If none are immediately effective, try again. You cannot count on one shot from a .338 win mag to stop a person. You have to put the shot in the right spot and then you'd better be ready for a back up.

    I'm not sure what all this arguing over Fackler vs Courtney accomplishes in the real world. I carry what I carry because it's small enough to easily conceal and I have confidence in my ability to make a shot with it and confidence in the round to do the job. Don't need math to figure that out. :rolleyes:
     
  10. ArchAngelCD

    ArchAngelCD Senior Member

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    Neither, IMO ACCURACY is most important because the best bullet in the world traveling fast and hitting hard will do little to no good unless you make good hits. If it comes down to a few fps choose the ammo that's most accurate in your handgun.

    Decades ago when bullet construction was poor a wide heavy bullet moving fast was necessary. With today's bullet technology a JHP bullet can be traveling as slow as 800 fps and reliable expand. ACCURACY is the key...
     
  11. CraigC
    • Contributing Member

    CraigC Senior Member

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    Neither. Both are great excuses for shooters to turn off their brains. In the real world, where lead and copper meet flesh, it's far more complicated. What matters firstly, where the bullet lands. Secondly, what does said bullet do at a given velocity? Does it expand AND penetrate sufficiently, providing ample tissue destruction? Or does it just punch a clean hole? Or does it expand too quickly, yield a nasty, shallow wound? Unfortunately, there is nothing in a ballistics table or mathematical formula that will tell you the answers to these questions. Yet shooters remain obsessed with velocity and that most useless of all numbers, kinetic energy. :rolleyes:


    Exactly!
     
  12. brickeyee

    brickeyee Senior Member

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    Only if you want to pretend that the "soft tissue" is uniform and nothing else is present.

    Like muscle vs. fluid filled organs, or even air filled organs (like lungs).
    It just does NOT work and devolves into a waste of time.

    You are free to waste as much time as you want.

    There are simply so many variables that it is not possible a priori to tell what A bullet is gong to do in A target with an arbitrary path.
     
  13. Skribs

    Skribs Senior Member

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    I don't look at any of the numbers at the muzzle, I look at the numbers in the target. Bullet design will mean much more about what happens at impact than the muzzle energy. I look at test results - how far does it go, how wide does it get?
     
  14. 481

    481 Senior Member

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    Despite your insistence to the contrary, there are accurate models (in Bullet Penetration by Duncan MacPherson and Quantitative Ammunition Selection by Charles Schwartz) that predict the penetration of expanding and non-expanding bullets in calibrated ordnance gelatin which is meant to simulate the terminal behavior of projectiles in soft tissue so it is not without basis that such an application of these models can be made.

    By way of example, Duncan MacPherson addresses on page 223 of Bullet Penetration, the validity of applying these models' yields to a projectile's terminal behavior in soft tissue given the problems associated with the employment actual soft tissue as a test medium-

    For this reason, both models (as proposed by Schwartz and MacPherson) relying upon calibrated ordnance gelatin testing data as they do, are suitable for the prediction of the terminal behavior of expanding and non-expanding projectiles in calibrated ordnance gelatin and soft tissue regardless of the particular isotropism of either test medium.
     
  15. golden

    golden Senior Member

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    Neither are important beyond a minimal amount

    Duke,

    If velocity is that important, then the 5.7 m.m. round used in the FN pistols and submachinegun would be top of the hill, but no police department or federal agency I know of is issuing one.
    If energy was most important, then cops would be carrying .44 magnums or full velocity 10 m.m. pistols. Very few cops do and no agency issues them.

    Recoil mitigation and an effective bullet are much more important.
    A heavy non-expanding bullet can penetrate deeply, but may pass through a target with causing much damage. The deer may bleed out and an exit wound increases the blood loss and creates a more visible trail.
    That is fine in deer hunting, it is not a good thing in a gunfight. Deer rarely are trying to kill you,

    Velocity produces energy and energy is what tranforms a hollowpoint into an expanded hollowpoint and controls the amount of penetration, but so do other factors.

    Hign energy is often achieved by raising the velocity of a round. To do that, pressure has to increase, so noise, flash and muzzle blast may also increase.
    The noise and muzzle blast are factors that have worked against the .357 SIG round, which by all the accounts I have seen is a very effective round.

    Recoil is also a big factor and for some persons, it may be huge. Recoil controls recovery time, you can improve training and the grip material, but recoil is hard to mitigate.

    Is it more important to get a second shot fired into the target or possiblely a second target or do you need a more powerful round?

    I have decided to stick with the 9m.m. +P or +P+ in most of my defensive pistols. I think it has enough power and the recoil is controlable in mid size and larger guns. In compact and mini-pistols, I would go with standard 9m.m.

    I shot a RUGER LC9, a couple of months ago. It worked as advertized, but was so unpleasant to shoot, I decided not to buy one. I knew that I would not be able to practice with it enough to feel comfortable.

    The same thing holds true in revolvers. Many agencies preferred heavy, hollowpoint .38 Special loads to much more powerful .357 magnum ammunition for issue to their officers.

    Just my opinions.

    Jim
     
  16. 2zulu1

    2zulu1 Senior Member

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    Being retired I get to choose how I "waste" my time, but thank you for caring. :)

    Given your response, do you believe bullet designers use software to calculate how a bullet expands and are able to design it to perform to a designated penetration depth in soft tissue?

    While I'm not as knowledgeable in physics as you are, given your self appointed status, I believe both MacPherson and Schwartz to be more knowledgeable on this subject than you. :)
     
  17. mr.trooper

    mr.trooper Senior Member

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    Neither. In a world where a .32acp FMJ can exceed 16" of penetration from a pocket pistol, and a .22LR can reach 12" of penetration from a 4" plinker, why would you be worried about velocity or energy?

    Neither of those cartridges have very much of either one (velocity or energy), but a properly placed pill from either will shut someone down in an instant. So therefore, why would you worry at all about such things when you are using something more potent?

    Any cartridge at all that can reliably reach vitals with a hollow point (9mm Mak on up) would be an acceptable choice, as handguns don't do any additional tissue 'shock' anyway - they poke holes in things and let the blood out. Unless they happen to sever an important nerve bundle in the process, they will all be poor stoppers.

    Just a quibble, but you didn't look very hard. The 5.7 pistol is currently issued to elite units by 19 foreign militaries. Here in the USA it is used by the US Secret Service as well as the Duluth GA police department and the Passaic county NJ SWAT.

    The P90 sub-machine gun is in use by 45 foreign militaries. Here in the USA it is in use by the US Secret Service, ICE, Immigration, 9 local and state agencies including the Alaska State Troopers, and 5 SWAT teams around the country. At least one local LE agency issues the P90 to patrol officers as a vehicle weapon.

    No, the pair is not as common as Glocks or the MP5, but they are out there and they do see real use. If you want to check my figures just zip over to wikipedia - the sources and citations for both of these weapons are very well developed and maintained.
     
    Last edited: Nov 16, 2012
  18. golden

    golden Senior Member

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    Wrong trooper

    TROOPER,

    Which agencies is it exactly that issues 5.7 m.m. pistols for street use? What military ISSUES ONLY THE Five-SeveN pistol WITHOUT also using the P90 submachine gun.

    A round fired by the P90 is in a completely different class. As you mentioned, departments issue 9m.m. pistols and MP5 submachine guns. If they are the same, why issue both. Obviously, a round from the P90 is going to be more accurately delivered as well firing full automatic. You cannot compare apples and oranges.

    You also mentioned a NJ SWAT team. I am talking about issue to street officers and detectives by a major department. Do you know any? I do not.
    If velocity is so important, why then are not the federal agencies, state police, county and city LEO agencies not issuing GLASER SAFETY SLUGS as standard issue. Why are they not carrying a round like the French ARCANE ammo that sent a 9m.m. bullet at over 2,000 fps.

    Velocity is not the end all, it is just one of the components.

    Jim
     
  19. brickeyee

    brickeyee Senior Member

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    Do you understand what 'simulate" means?

    the lazst time a block of ge;atimn (orimamce or tother0 attacked nyone i am sure you could calcluate how a ullet penetrated.

    It is a MODEL.

    ALL MODELS ARE WRONG, SOME MODELS ARE USEFUL.

    There is NO model that is truly useful for determining the path, penetration, and effect of of a bullet through anything as complicated as human anatomy, let alone any other animal.

    Even is you fired the same bullet at the same point on different people, you are unlikely to end up with the same result.
     
  20. 481

    481 Senior Member

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    Yep. Calibrated ordnance gelatin simulates the average density and strength of soft tissue. The result that calibrated ordnance gelatin (or a model that predicts terminal ballistic performance in calibrated ordnance gelatin) yields is a predicted average of what the bullet will do in soft tissue.

    Not sure what you are going for here.

    All models (like F=ma, mv=mv, etc.) have some degree of inherent error, but that doesn't mean that they are invalid if they aren't absolutely without error/uncertainty. The Schwartz and MacPherson bullet penetration models are relatively accurate and very useful. Just because they are not absolutely perfect does not mean that they must be discarded.

    The MacPherson bullet penetration model (n = 400+, "r" and MoE are not stated by MacPherson) and the Schwartz bullet penetration model (n = 700+, "r" = 0.94, MoE = 1 cm) accurately predict the behavior of bullets in calibrated ordnance gelatin which produces results (expansion, terminal penetration depth, etc.) that match closely those produced in human bodies.

    It is hardly a great leap to model this sort of behavior in predominantly isotropic mediums like ordnance gelatin- it is done all of the time in related fields like aero-dynamics and fluid dynamics.
     
    Last edited: Nov 17, 2012
  21. Shawn Dodson

    Shawn Dodson Senior Member

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    Properly prepared and calibrated ordnance gelatin provides an engineering evaluation tool to test JHP handgun bullet penetration and expansion performance in a realistic soft tissue simulant. In a defensive scenario, all of the VITAL tissues that we're trying to damage are ALL soft tissues. JHP bullets are designed to expand in soft tissues. A modern JHP handgun bullet recovered from a body closely resembles the same bullet that has been tested in ordnance gelatin.

    Reliable rapid incapacitation is caused only by what vital structure(s) a JHP handgun bullet comes into direct contact with and how much damage it produces to that structure (wound severity). TYPE of tissue and AMOUNT of damage are what's important.
     
  22. fastbolt

    fastbolt Senior Member

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    There was a day, when I was a younger shooter, when I paid close attention to the listed MV & ME.

    In subsequent years I paid much less heed to such things, preferring to focus on weapon reliability with various ammunition, maintenance ... and my ability to put hits on an intended threat target in an effective & timely manner.

    Nowadays I can also look for better hollowpoint designs for use as dedicated defensive ammunition, too.

    As long as the loads keep the bullets running in the optimal velocity window for them to function as intended, regardless of barrel length (full-size, compact, subcompact, snub nose, etc) ... I'm free to focus on the weapon & shooter influences.

    I see the shooter influences (mindset, training, practice, employment of tactics, etc) as the arguably more critical influences, anyway.

    So ... ballistics? In a handgun? Sure. Suit yourself. Just don't let it distract you from the more critical considerations.
     
  23. fastbolt

    fastbolt Senior Member

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  24. otasan56

    otasan56 Member

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    I rely on Muzzle energy

    to establish bullet effectiveness. My 9x19 115gr JHP gives 400 foot-pounds of energy, and this is pretty good for a 9mm. ;)
     
  25. brnmw

    brnmw Member

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    There is a loaded question... get ready for the slug fest! (If it has not started already that is.)
     

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