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Which is more important in ballistics?

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


    IMTHDUKE Well-Known Member

    In a defensive rd for a handgun which is more important to consider....muzzle velocity or muzzle energy?
  2. 481

    481 Well-Known Member

    Momentum at impact (mass times impact velocity) and what the bullet hits. So...velocity.

    Last edited: Sep 22, 2012
  3. Doc3402

    Doc3402 Well-Known Member

    If you mean the ratings on the box of ammo, neither one. Too many things can affect the actual MV and ME. Barrel length and handgun condition are the two most obvious.

    481 makes a very good point, but I think it's slightly misstated. Energy at impact is what I think he meant. Cross-sectional design is also important. More energy will be transmitted to the target if you use a flat nosed bullet than if you use something pointy.

    Since you did state handgun in your post I think it's important to understand that shot placement is probably your most important consideration. For all intents and purposes hydrostatic shock is not a factor in most handgun calibers. The velocities are too slow.
  4. 481

    481 Well-Known Member

    Nope, I meant momentum.

    Newton's laws of motion dictates how a bullet will behave as it penetrates soft tissue. The forces acting on the bullet arise from a decrease in momentum brought about by a change in its velocity (deceleration, in this case) are expressed as F = ma, so momentum is indeed what I meant.
    Last edited: Sep 22, 2012
  5. Rexster

    Rexster Well-Known Member

    If it can make a hole, reliably, deep into the important bits, that is what is most important.

    Velocity IS a component of energy. Muzzle velocity IS a component of muzzle energy. If all else stays the same, as velocity goes up, so does energy.
  6. 481

    481 Well-Known Member

    Velocity is also a component of momentum, hence p = mv. Penetration is a direct function of momentum and the best way to look at events of this type.
  7. Zak Smith

    Zak Smith Moderator Staff Member

    Check the FBI protocol for testing terminal ballistics. It uses neither.
  8. btg3

    btg3 Well-Known Member

    Velocity is just velocity.
    Energy includes mass and velocity -- making it more significant than velocity alone.

    The question is flawed. As noted by other posters, there are more significant factors to consider.
  9. 1911Tuner

    1911Tuner Moderator Emeritus

    Velocity...Energy...Momentum. All part of the equation, and all variable. Mass is the only constant. The British worked it out two and a half centuries ago. "Heavy ball/Light charge."
  10. scaatylobo

    scaatylobo Well-Known Member


    In my not so humble opinion.

    Its accuracy and YOUR ability to hit a small moving target with ANY caliber.

    After that,my vote goes to ability to penetrate soft tissue to a depth of 10 or 12 inches.
  11. Kleanbore

    Kleanbore Moderator

    Neither. Given the same mass, energy is determined by velocity.

    Energy, or work, is one of the several things that determine penetration. Penetration and diameter determine effectiveness, along with point and direction of impact.

    There are people on the wonderful world wide web who contend that momentum is the determinant of penetration, usually in the context of archery. They could use a physics course. Momentum will define two things: recoil, and how fast the target with the bullet in it will move after impact. The latter is very insignificant.

    Consider that braking distance of an automobile varies with the square of the velocity. Same thing.
  12. 481

    481 Well-Known Member

    Duncan MacPherson, an MIT educated Aerospace Engineer, seems to believe otherwise and argues below that momentum is a valid way to model terminal ballistic behavior to include penetration. His momentum-based model predicts penetration and I doubt that anyone could argue that he is in need of a physics course. :confused:

    Excerpt from "Bullet Penetration" by Duncan MacPherson:
  13. 2zulu1

    2zulu1 Well-Known Member

  14. MachIVshooter

    MachIVshooter Well-Known Member

    Muzzle energy is the easiest/quickest way to compare the relative capability of cartridges, but it's certainly not the only thing to consider, and you have to keep it in the same ballpark (for example, a .223 from a rifle and a .44 mag from a handgun have similar energy, but very different wounding mechanisms).

    KE does largely determine a cartridge's ability to do work, work being bullet expansion & penetration. But it's not universal; The weight and construction of the bullet have to be appropriately matched to the power to achieve the desired performance. You can push a 90 gr. bullet out of a 9mm to velocities that will rival the energy of moderate .357 mag loads, but that .357 will be using a 125, 140 or 158 gr. bullet that is designed to hold together and acheive penetration, whereas that 90 gr. .355" pill is meant for the 900-1,100 FPS velocities of a .380, and will literally blow up in the medium when driven to 1,600+ in a 9x19mm +P load. So even though both that 9mm 90 gr. load and .357 mag 158 gr. load will generate around 550 FPE, the .357 load will be far more effective.

    My personal feeling for defensive handguns is that more energy is better up to the level of full house 10mm, but it should be achieved using mid to heavy weight bullets for the caliber. Heavy bullet loads will have lower energies than the lighter bullets in a given cartridge, but almost universally achieve deeper penetration. I'd rather have a 124 gr. 9x19mm load making 375 FPE than the aforementioned 90 gr. load at 550 FPE.
  15. R.W.Dale

    R.W.Dale Well-Known Member

    I'm gonna give the same answer as I dis on the other forum Whee you asked this

    The only thing that matters is what you put a bullet hole in.

    Velocity and energy don't stop bad guys or kill game in the field. Bullet holes on the otherhand do.

    You need shot placement, penatration, reliability and then energy-expansion
  16. MachIVshooter

    MachIVshooter Well-Known Member

    That's kinda the whole point of considering energy and momentum. A perfectly placed shot that dos not achieve adequate penetration is no better than a poorly placed shot that gets through but misses the structure. And a big hole is better than a small hole. To achieve that adequate penetration and large hole, you need energy and momentum.

    No one is arguing that shot placement isn't top priority, but it would be asinine to imply that a 3mm Kolibri can be as effective as a .45 ACP with a hole in the same place. Stopping an attacker isn't popping a balloon. Ballistics matter.
  17. R.W.Dale

    R.W.Dale Well-Known Member

    Its no less asinine to imply that massive amounts of energy or velocity (at handgun levels) in any way make up for inferior shot placement.

    Folks watch slow motion gel tests of modern jhp's in service handguns and get this false impression that the human body cannot cope with what they're seeing in the gel. This is a false assumption bourne out by the fact that over 80% of handgun gunshot victims survive
  18. WardenWolf

    WardenWolf member

    From what I've seen in ballistics tests on Brass Fetcher, velocity matters a lot more than bullet size or weight. For example, comparing 7.62x25 (a .31 caliber projectile) to 9mm (a .357 caliber projectile), both using Speer Gold Dot hollowpoints, the Tokarev round is noticeably more destructive, inducing greater hydrostatic shock that is also much more violent (it produces a VERY pronounced cyclonic effect). Note that the Tokarev round is moving around 1400 FPS, whereas the 9mm round is moving around 1200 FPS. Bullet weight was 115 grains versus 124 grains.

    Another example of this is exhibited with .45 ACP ammo. The heavier 230-grain bullet was very unimpressive, exhibiting worse performance than the 9mm round. However, the 203-grain bullet, with its higher velocity, proved devastating, far more so than 9mm. Again, both bullets were Speer Gold Dots. Velocity once again shows itself to be the key factor.

    Of course, velocity also translates directly to muzzle energy. Because of the way energy is calculated, a lighter bullet traveling at a higher velocity often carries more energy than a heavier bullet traveling slower. Comparing from 124 grains at 1200 FPS in 9mm to 115 grains at 1400 FPS in 7.62x25, you lose approximately 8% of your weight, but gain more than 28% velocity, making for a substantial increase in overall energy.
    Last edited: Sep 23, 2012
  19. MachIVshooter

    MachIVshooter Well-Known Member

    Are you just wanting to argue for the sake of arguing? I have to assume so, since I made it clear that:

    Hydrostatic shock is not a reliable wounding mechanism at handgun velocities. Bullets moving slower than ~2,000 FPS do damage by crushing and tearing tissue directly contacted by the bullet. Yes, there is often some peripheral damage done by the temporary cavity, but again, that is not a reliable component with handgun rounds. Unless you're a Michael Courtney deciple, in which case reality isn't relevant...........
  20. WardenWolf

    WardenWolf member

    Well, it depends. The Tokarev's hydrostatic shock was actually cyclonic. It was twisting, not just expanding. That would cause a lot more damage with regards to tearing tissues apart.

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