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Which is more important in ballistics?

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

  1. R.W.Dale

    R.W.Dale Elder

    Oct 14, 2005
    Northwest Arkansas
    Its my observation that handgun cartridges seem to fall into groups it tiers of similar effectiveness when loaded with top tier defense loads for each.

    Sub service or "pocket" pistol calibers

    32-380-38spl ect

    Not terribly effective, IMO best used with the deepest penatration loads for each expansion severely hampers penatration

    Service calibers

    9-40-357sig-mag-45 ect

    Can drive modern expanding ammo hard enough to provide adequate penatration.

    Hunting calibers or magnums

    44mag-hot colt-10mm-some357-ect

    Can drive bullets too hard if careful selection isn't made. Doesn't seem to bring anything to the anti 2 legged defense role compared to service calibers.

    Then IMO you have a fourth set of big bore calibers that retain a satisfactory level of effectiveness sans expansion starting with 44spl +

    Within these tiers terminal performance is so similar that factors of accuracy, recoil, platform and capacity become the primary considerations. With a few cartridges like 38spl, 10mm, 357mag and even 45acp having the ability to bridge the gaps in between depending on the platform and exact loading
  2. btg3

    btg3 Participating Member

    Oct 30, 2007
    True or false... Selection of handgun caliber will make the greater difference as compared to selection of a particular self-defense load within a given cailber.
  3. Frank Ettin

    Frank Ettin Moderator

    Apr 29, 2006
    California - San Francisco Bay Area
    Been through this before, but let's do it again.

    There are four ways in which shooting someone stops him:

    1. psychological -- "I'm shot, it hurts, I don't want to get shot any more."
    2. massive blood loss depriving the muscles and brain of oxygen and thus significantly impairing their ability to function
    3. breaking major skeletal support structures
    4. damaging the central nervous system.

    Depending on someone just giving up because he's been shot is iffy. Probably most fights are stopped that way, but some aren't; and there are no guarantees.

    Breaking major skeletal structures can quickly impair mobility. But if the assailant has a gun, he can still shoot. And it will take a reasonably powerful round to reliably penetrate and break a large bone, like the pelvis.

    Hits to the central nervous system are sure and quick, but the CNS presents a small and uncertain target. And sometimes significant penetration will be needed to reach it.

    The most common and sure physiological way in which shooting someone stops him is blood loss -- depriving the brain and muscles of oxygen and nutrients, thus impairing the ability of the brain and muscles to function. Blood loss is facilitated by (1) large holes causing tissue damage; (2) getting the holes in the right places to damage major blood vessels or blood bearing organs; and (3) adequate penetration to get those holes into the blood vessels and organs which are fairly deep in the body. The problem is that blood loss takes time. People have continued to fight effectively when gravely, even mortally, wounded. So things that can speed up blood loss, more holes, bigger holes, better placed holes, etc., help.

    So as a rule of thumb --

    • More holes are better than fewer holes.
    • Larger holes are better than smaller holes.
    • Holes in the right places are better than holes in the wrong places.
    • Holes that are deep enough are better than holes that aren't.
    • There are no magic bullets.

    And sometimes a 9mm might not be enough because sometimes even a .357 Magnum isn't necessarily enough. LAPD Officer Stacy Lim was shot in the chest with a .357 Magnum and still ran down her attacker, returned fire, killed him, survived, and ultimately was able to return to duty.
  4. MachIVshooter

    MachIVshooter Elder

    Aug 11, 2005
    Elbert County, CO
    That's not a question so easily answered. The absolute, top-dawg premium load in a .32 ACP is still not going to be as effective as a .44 Spl. cowboy load.

    On the other hand, a good, modern JHP 9x19mm load will likely outperform a .45 ACP FMJ.

    Best answer: Choose a capable cartridge, find a platform that suits your needs, choose a quality load that performs well, then practice, practice, practice.

    My absolute minimum for a defensive round is 200 FPE with a good bullet, whether it's a .380 or a .32 H&R magnum. Anything less than that, you're either making too small a hole or not getting enough penetration (or both). Whenever possible, I carry 10mm. It's got the power to drive a heavy bullet deep and expand it wide in any 2-legged threat.
  5. MikePGS

    MikePGS Senior Member

    Aug 4, 2006
    Metro Detroit, Michigan
    "Placement is power." Stephen A. Camp
  6. easyg

    easyg Senior Member

    May 19, 2007
    off-line mostly.
    No one here is making this argument.

    Everyone here agrees that shot placement is of the utmost importance.

    But that does not mean that caliber, velocity, energy, and bullet design doesn't matter.
    All of that matters a great deal.

    As for the original question....which is more important, velocity or energy?
    Energy is more important.

    Whether one prefers a heavy and slower high energy round, or a light and faster high energy round, it does not matter so long as adequate energy is reached.

    Now exactly what is the adequate amount of energy?
    That is the real debate.

    I think that any handgun load that offers 400+ ft. lbs. of energy will work just fine for stopping aggressive human threats, so long as it's not too powerful for the shooter to quickly and accurately put lead on target.
  7. 481

    481 Participating Member

    Feb 22, 2009
    I agree.

    Most people do not realize that the T/Cs shown in those videos are nowhere near large enough to exceed the elastic strength of the vast majority of the tissues that a bullet will travel through as it passes through a human body.

    The T/Cs in the videos appear to be impressive, but as they say- "Appearances can be deceiving."

    BADUNAME37 Senior Member

    Aug 10, 2008
    This is one of those arguments that has no right or no wrong answers.

    It all depends on exactly what is being shot -- at exactly what distance -- and, whether or not overpenetration can (or cannot) be an issue.:rolleyes:
  9. Kleanbore

    Kleanbore Moderator

    Aug 13, 2008
    MacPherson is correct when he observes the following:

    But: the fact that momentum is conserved in either an elastic (think billiard balls) or inelastic (punching bag) collision does not have a thing to do with penetration. It simply enables one to determine the velocity of the target with the bullet in it if one knows the mass of the target, the mass of the bullet, and the velocity of the bullet upon impact, and if the bullet does not exit the target. McPherson would agree with that, were he alive today. But that's something one does not need to know.

    One can also solve for the bullet's velocity upon impact by working backwards from the mass of the bullet, the mass of the target , and the velocity if the target plus the bullet after impact. Again, the equations used for that purpose involve momentum. That's how a ballistic pendulum works. At least some of us have done that in engineering school. I did it in high school, too. One wold not measure velocity that way today, but it's and excellent teaching device.

    The conversion of kinetic energy into thermal energy is part of what stops the bullet--i.e., what determines penetration--just as the heating of your brakes is what stops your car. The kinetic energy prior to impact is therefore a major determinant of penetration, (how far the bullet travels into the target after impact), and your car travels after the brakes are put on.

    What it takes to put your car or a bullet into motion is work, which is by definition energy, thermal and kinetic. It's the same thing when it comes to stopping either one, or anything that is moving, for that matter. That's indisputable. And no, I wouldn't attempt to model it. But one can measure the behavior of the items. Many of us have done that. too.

    Penetration in a given substance will be determined by a number of things, including the shape of the bullet, the mass, how it deforms, and how fast it is going. But it is the square of the velocity with which penetration will vary, all other things being equal.

    Back to the OP's question: what determines a bullet's effectiveness is what it damages. And adequate penetration is a big part of the answer to that question, along with wound channel and where the bullet strikes. That's consistent with McPherson's conclusions.

    By the way, at handgun velocities, the only important thing that energy affects is penetration. Forget "energy dump", "shock", whatever. That's consistent with McPherson's conclusions, too.

    Just an aside: the term "hydrostatic shock" is a misnomer. I'm a little embarrassed to say that I ate that stuff up while reading Jack O'Connor's books about hunting rifles at the same time I was studying engineering. I should have known better. But we all know what people mean when they use the term.
  10. coalman

    coalman Active Member

    Mar 23, 2012
    Momentum. I favor mass. I want heavier moving as fast as possible opposed to lighter moving as fast as possible.
  11. 2zulu1

    2zulu1 Participating Member

    Jul 18, 2011
    I'm not sure how billiard balls or punching bags relate to fluid dynamics, but I do use MacPherson's book as a reference source. I needed tutoring to grasp some of the formulas he used to validate the momentum model as it related to bullet penetration. An engineer should not have any issues understanding MacPherson's empirical research.

    Here's a link to Double Tap's gel data for a number of handgun bullet designs and calibers.


    As we can see, there is a bullet penetration overlap between calibers independent of kinetic energy. Of particular interest for our discussion is the comparison between the much higher KE 10mm/180gr Gold Dot and the 45auto/230gr Gold Dot. In spite of the fact that the 10mm had a significant KE advantage, both bullets expanded to the same diameter and penetrated the same distance in ballistic gel.

    Given equal expansion, the 230gr Gold Dot retained more of its sectional density than the 180gr. Both bullets are in the same sectional density group and both loadings basically share the same momentum.

    Given McNett's ballistic gel data, there still isn't any way to predict wound trauma Incapacitation times.
  12. 1911Tuner

    1911Tuner Moderator Emeritus

    May 22, 2003
    Lexington,North Carolina...or thereabouts
    I'm also in the mass/momentum corner, but with higher and higher velocities, you can reach the point of diminishing returns. Newton 3 will spoil the show. The harder the bullet hits the target, the harder the target hits the bullet. This is why a car being pushed for absolute top speed eventually runs into a stalemate with the wind...which is essentially "penetrating" a fluid medium.

    Studying long-range ballistics tables will reveal much on this issue.

    Two .30 caliber bullets with similar shapes and BCs...150 and 165 grains at 2800 fps and 2600 fps initial velocities...the lighter, faster bullet loses a greater percentage of its initial velocity at 100 yards than the heavier, slower bullet. At 400 yards, the speed gap is rapidly closing. At about 500 yards, the 165 catches the 150 and passes it, beating it in both energy and momentum.

    Certainly the ballistic coefficient factors in, but there's more to it than simply that. Sectional density and how efficiently the bullet conserves its momentum are equally important. Here, the advantage goes to the more massive/heavier bullet. The old-timers observed this, and they said that the heavy bullet "carried" better than the light one. The 19th century buffalo hunters favored heavy bullets for good reason, even with lower velocities and rainbow trajectories.
  13. bikerdoc

    bikerdoc Moderator Staff Member

    Jan 8, 2008
    Southern Virginia
  14. calaverasslim

    calaverasslim Participating Member

    Jul 20, 2005
    San Antonio de Bejar
    Your all way above me. Energy, Muzzle velocity etc etc etc.

    I want a larger caliber bullet, with enough ooomph to put the bad guy down. 9 or 10 or 41 or 44 or 45, whatever I am proficient with and can get a good solid hit.
  15. Kleanbore

    Kleanbore Moderator

    Aug 13, 2008
    This review of Duncan McPherson's book ssems to get right to the net upshot, as an engineering professor of mine used to say.


    The same things are concluded in the FBI Handgun Wounding Factors and Effectiveness report.

    Knock down power and shock are notably missing from both.

    While McPherson (1) showed how it is possible to predict penetration in gelatin from momentum data and from the expansion behavior of the bullet in water and (2) pointed out that kinetic energy (the effects of which many people incorrectly refer to as to as "hydrostatic shock") does not determine projectile effectiveness alone, I really do not think he ever believed that momentum really determines penetration in an inelastic collision; that would go against the laws of physics. He was able to correlate penetration with momentum, given other information that takes into account the effects of, among other things, energy.

    Personally, I have no interest in trying to model penetration myself. There are far too many variables. One can learn all one needs to know about penetration in gelatin, through glass, metal, and fabric, from other people's work, and even then the penetration into a 'real' target will be what it turns out to be.

    Slow heavy bullet or lighter faster one? Well, in practice, proper "placement" in a three dimensional fast-moving target is to a large extent really a matter of luck, so more rounds, and less recoil, are also key advantages. They help with Frank's contribution that more holes are better than fewer holes and holes in the right places are better than holes in the wrong places.

    By the way, lower recoil means less momentum or a heavier firearm.
  16. 481

    481 Participating Member

    Feb 22, 2009
    Well, it seems that he does, and with good reason-

    From pages 7 & 8 of Bullet Penetration by Duncan MacPherson:
    Momentum is conserved even in inelastic collisions. MacPherson explains this later in the chapter that I've quoted from (above). If you haven't read the book, I'd recommend it highly. The Schwartz bullet penetration model is also directly derived from F=ma, Newton's second law of motion, which describes momentum transfer (aka "impulse"). I find it hard to believe that both Schwartz and MacPherson are incorrect in their position.

    If there were too many variables, you wouldn't have the various soft-tissue penetration models set forth by MacPherson (n=400+), Schwartz, (n=700+) and CE Peters (n= ???).

    All of them take into account all of the necessary variables, are highly correlated, and quite accurate.
  17. MistWolf

    MistWolf Senior Member

    Aug 17, 2005
    Neither one. What's most important is terminal performance. Whether using a light fast bullet or slow heavy bullet, what really counts is what that bullet does once it hits the target.

    The bullet has to carry enough velocity and weight to get the job done but both are really only a part of the whole picture. Bullet construction has to match velocity and weight to optimize terminal performance. What difference does it make if a bullet is light & fast or heavy & slow if it leaves a long narrow wound channel, or a shallow one because of poor bullet construction and shape?

    The FBI specifies pistol ammo must meet a minimum and maximum penetration in ballistic gel (among other criteria). To meet the specifications, manufacturers must balance velocity, mass and construction to give the best terminal performance. Complicating things further is other mission needs such as penetration of barriers, shooting through heavy clothing, price and so on. It's also known that pistol calibers suitable for a duty handgun are unreliable fight stoppers meaning more than one round will probably be needed to stop the altercation.

    When selecting self defense ammo, the only thing that's important about velocity and mass is whether or not the load offers enough of both to get the job done. Even so, neither will do any good if the bullet constructed improperly, resulting in poor terminal performance
  18. Kleanbore

    Kleanbore Moderator

    Aug 13, 2008
    True, and so I have said. But that does not mean that momentum is the determinant of the distance that an object will travel after being captured in an inelastic collision.

    To stop a moving object it is, as you certainly understand, necessary to apply a force to it. And in an inelastic collision, that force involves converting kinetic energy into other forms of energy and/or transferring it to other objects. McPherson said as much.

    In stopping a car or truck or a train, friction brakes convert KE to heat, and regenerative brakes convert it to electrical energy.

    And guess what: given a constant braking force, the stopping distance is proportional to the square of the initial velocity--to kinetic energy. When I was young, every college freshman studying engineering performed calculations and experiments showing that.

    And penetration is nothing but stopping distance.

    Things get a little more complex when it comes to the stopping an airplane on a carrier, where the brakes convert some of the kinetic energy to heat, and some of it is transferred to the arresting equipment; and in addressing the the slowing a vehicle reentering the atmosphere from space, where kinetic anergy is converted into heat, until aerodynamic drag takes over, and perhaps unless a parachute is deployed to shed much of the remaining kinetic energy.

    If two billiard balls collide (elastic collision), kinetic energy is conserved as kinetic anergy. But if a car smashes into a deformable building, its kinetic energy is shed in several ways--into heat, into material that is put in motion, and so on. The same thing is true in bullets.

    As McPherson said, "kinetic energy is not only not conserved in real collisions, but is transferred into thermal energy in a way that usually cannot be practically modeled." So he decided to come up with correlative models based on momentum. But it would be a mistake to conclude that he ever believed that the stopping distance of a car under a braking force (a far easier thing to model--I've done it) was proportional to momentum. Because it is not, and never has been.

    I've thought about it. I have long ago accepted his conclusions about what causes wounding and what does not, but I have no interest in reading about his correlative modeling of penetration, however brilliant it may be.

    I'm not one of those fires bullets in to gelatin or pays a lot of attention to test results. I've chosen my carry loads, and I do not continue to meditate about how far a single bullet would go into gelatin.

    I do stay up with those fine people here who opine about big and slow vs light and fast, but I do not concern myself much about what a single bullet properly placed would do under ideal circumstances.

    So, when it comes to momentum vs energy, I will likely choose low momentum over high, to keep recoil down. And even though a bigger bullet is more effective than a smaller one, there's the issue of round count to keep in mind.

    I am not disputing McPherson's assertion that many people have placed too much emphasis on kinetic energy in assessing wounding effectiveness. Full disclosure: until some years ago, I was among them.
  19. Kleanbore

    Kleanbore Moderator

    Aug 13, 2008
    Say again? Really?

    Well, yeah, and that's why I can't get too interested in choosing a firearm on the basis of its performance with a single hit under ideal circumstances.

    Experts can certainly make informed judgments on what hits would be most effective. They'll say CNS, but that does not mean that anyone would recommend aiming for the brain of a moving target in a violent encounter.

    I's pretty well accepted that one should aim for center mass and shoot more than once. A hit to the upper spinal column, or to the ulna 0f the arm holding the gun, or to a tendon holding the knife or maybe a few more....
  20. 481

    481 Participating Member

    Feb 22, 2009
    Actually, it is. It is called transfer of momentum. This occurs through the action of a force exacted upon a bullet by contact with a medium which causes it to decelerate. It is F = ma or more specifically F = m ∆v/∆t, which indicates a transfer of momentum. Your statement here says just that:

    It is also a momentum transaction.

    That's a good example of F = m (-a) and it is still a mometum transaction. -think "impulse"-func. (F/∆t)--- [ m; ∆v/∆t; ∆v/∆x
    Last edited: Sep 26, 2012

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