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Velocity vs Bullet weight. Here we go.

Discussion in 'General Gun Discussions' started by JRWhit, Oct 18, 2013.

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  1. JRWhit

    JRWhit Member

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    This recent thread on this police shooting reopened a contrast in my mind. http://api.viglink.com/api/click?fo...eo_capt.html&jsonp=vglnk_jsonp_13820928290106
    In this video it is hard to determine when the perp was actually hit by the round shot from the officer and shows little effect on the perp even though it proved to be fatal. This once again raises the question to me of higher velocity vs heavier bullet weight. In hunting I have seemed to experience that while a heavier projectile will in many cases do more damage, a faster moving lower weight projectile will have a more incapacitating effect overall even if not a fatal shot. For me it brings to question the effects of the shock wave that reverberates through a target and it's ability to incapacitate the target either from psychological, or muscular response to the shock wave. It would seem from hunting experiences that the higher velocity rounds offer a longer span of immobilization after impact than the heavier, slower moving projectiles,even in cases where the heavier projectile does more damage. Namely the difference between a heart shot that drops vs a heart shot that runs 50yds. This video reignited this question for me. Would a faster moving projectile of a lighter bullet weight offer a longer period of immobilization after impact due to felt shock wave and greater perceived injury by the perp?
    Let the firestorm of thoughts and opinions fly.
     
  2. Fast Frank

    Fast Frank Member

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    My personal experience leads me to agree with your theory.

    Look for instance at the .17HMR. My first impression of the 17 grain bullet idea was that it's silly. The velocity of the round, however, makes it an explosive little smasher that blows things up. I am amazed at the little bullet every time I shoot something with it.

    When you compare that to the .38 Special 158 grain RNL...

    There you have a bullet that possesses several times the energy of the little .17, but doesn't do much but poke a hole.

    Sure, the .38 drives in deeper, and does way more damage, but it lacks the "Splat Factor" of the .17 HMR.

    I think in the end it's going to come down to the compromise.

    The "Best" bullet is going to have a combination of bullet mass and velocity that provides good penetration, while still maintaining the velocity for the "Splat Factor".

    It's also going to have as much power as possible, while not going to far and becoming difficult to control because of excessive recoil.

    It's going to be as large as possible to poke big holes, but not too big so that as many rounds as possible will fit in the magazine.

    The compromise I just described is what the .40 S&W was designed to be.

    Of course... That still leaves the "Light and Fast VS. Heavy and Slow" choices within that caliber alone.

    Personally, I tend to prefer the heavy ones for self defense, But that's just me. I tend to trust the penetration more than the splat. Your Mileage May Vary.

    Splat factor from velocity definitely adds something to the hit, but I just don't trust it as much as deep penetration and damage
     
    Last edited: Oct 18, 2013
  3. Outlaw Man

    Outlaw Man Member

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    I think its more a question of energy transfer. Every bullet has a known (calculated) energy at a certain distance. The question is how much that energy is and how efficiently it's transferred to the target. Size, structure, composition, and a host of other factors contribute to that. Obviously you want that energy to explosively, violently transfer to the target at just the right time. As you know, penetration can make all the difference, whether it's too much or not enough.

    Then there's that human adrenaline wild card. Go read Lone Survivor by Marcus Luttrel, or any of a number of reports on almost superhuman responses to gunshots. If the person immediately thinks, "I'm dead," the fight is over. On the other hand, it takes a LOT to kill a human. If you find one that knows that and is determined to finish the job, short of a central nervous system-destroying shot, I don't think it matters what bullet you use and how fast its going. You're going to have to hit him with several.
     
  4. Kleanbore

    Kleanbore Moderator

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    Within the realm of normal defensive handgun cartridges, you will not see "energy ... explosively, violently transfer to the target at just the right time."

    The mechanics of wounding involve two things: penetration and the diameter of the permanent wound channel. The net effectiveness depends upon what is hit and the physiology and psychology of the target.
     
  5. Pizzapinochle

    Pizzapinochle member

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    Is there a discussion thread on this incident? Would be interested in reading.
     
  6. leadaddict

    leadaddict Member

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    I think I remember reading that this was a .40S&W that the criminal was shot with. Do you know if that is correct?
     
  7. gdcpony

    gdcpony Member

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    Beat me to it.

    It comes down to bullet construction and the momentum it has at impact. A bullet's job is transfer as much energy to the target as it can at the right time after impact (penetration). Momentum is different from energy and you can google it and find that archers like myself will argue arrow weights vs speed for this reason till the sun burns out (arrows try and do the opposite of bullets and pass through the target expending as little energy as possible to cut more)

    Momentum (M) drives penetration. It is very closely related to Energy (E) so most use that. Regardless, the bullet should attempt to drive to a point before deforming. The faster it is moving the more M it has to do so.

    Too much though and the bullet will likely deform too quickly before vitals are damaged significantly. The target may survive or die depending on the damage done. Or I have seen some that didn't have the time inside the target to fully deform too which simulates too little, but it is actually too much again.

    Too little and it will not deform due to a lack of force placed upon it by target. While it may pass through, it will do so transferring any E to the target. In a living creature if the path of travel is through vital organs it will die, but more slowly and painfully.

    Bullet construction MUST match the purpose. It must match not only in weight, but in construction. I have seen 60gr .223 bullets take down deer. I have seen 90gr .257 bullets vaporize a groundhog. Construction is more important than weight IMHO. I would not try to figure exactly when my bullet will start deforming at a given speed on a given target. That is done by the maker. My responsibility is to choose the right one. I tend to use a mid weight projectile moving at a decent speed.

    Now in the video, I am betting that the bullet didn't deform as much as it should.
     
  8. Outlaw Man

    Outlaw Man Member

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    Totally agree, at least compared to most rifle cartridges. Doesn't stop me from wanting it, though. If I could conceal, deploy, and maneuver with a rifle the way I could a handgun, I'd be getting that type of energy transfer, too. :)

    While a normal handgun bullet doesn't yaw and fly apart inside human tissue on a regular basis, the maximum expansion and wound disruption is what you're going for and hoping happens at the optimum spot. It's not terribly different from a rifle. Just less overwhelming.
     
  9. buck460XVR

    buck460XVR Member

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    SD and hunting ammo are two different cans of beans. The only things similar between them is that every target hit will react differently and every gun owner has their own opinion as to what works best. Differences in shot placement of only a inch, especially with a handgun, can mean the difference between a bang-flop/one shot incapacitation or a non-lethal wound. Looking at ONE video or using ONE example of incapacitating/not incapacitating to make judgement as to the effectiveness of any round would be foolish. Use your heart shot example. Shoot a relaxed deer thru the heart with an arrow and it will be hard pressed to go more than 40 yards. Shoot a running deer full of adrenaline thru the heart with a .357 and it may go 100 yards....even tho the .357 does more tissue damage. There are just to many variables. Modern bullets are very well made and most major manufacturers spend lots of R&D monies designing bullets specific to their intended usage. That does not mean that bullet will work perfectly within all scenarios. We, whether we are looking for a SD round or hunting round need to know what parameters we are looking for in the bullet used in that round and use it accordingly. If we do our job with shot placement, odds are the bullet will also do it's job.
     
  10. Orion8472

    Orion8472 Member

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    That video gives me little encouragement, as a ccw. A "kill shot", yet the guy keeps going . . . . or could easily keep coming AT you. It seems that pretty much any handgun is merely a "better than nothing" tool that may still not save your life [even if the perp is killed too].

    It makes me want to be sure I'm never in a gunfight to begin with, so staying out of potentially risky areas or situations.
     
  11. Queen_of_Thunder

    Queen_of_Thunder member

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  12. MachIVshooter

    MachIVshooter Member

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    Oh, boy, here we go. Big 'ol can-o-worms opened. lol.

    For one, we call that anecdotal. Without many, many, MANY examples with variables made as consistent as possible and many other controls in place, you can't chalk it up to any more than shot placement and the individual state of the animals, both physically and psychologically. A larger, stronger animal hit in a place that does less damage to vital organs is going to appear less affected than his smaller, weaker counterpart drilled right through the heart & lungs.

    Secondly, rifles and handguns are not in the same league when it comes to wounding-not even the big magnums. Handgun rounds do not achieve the velocity to cause rifle bullet damage; they wound by crushing and tearing tissue directly in their path, with very little peripheral damage to the wound channel-especially in highly elastic tissues. Rifle bullets, due to their velocity, create a permanent cavity much larger than the bullet itself. We start to see these larger-than-bullet permanent cavities at speeds around 2,000 FPS.

    If you want to learn about this stuff more, I'd suggest searching on here, and elsewhere, paying particular attention to the likes of Martin Fackler and Michael Courtney. Those two will give you very different perspectives on bullet wounding mechanisms, including temporary and permanent cavity properties, the hydraulic shock theory, etc. Personally, though I respect his efforts, I remain unconvinced of Dr. Courtney's theory for many reasons. But it's still an interesting read.

    Common service caliber rounds actually vary little in the kinds of wounds they leave; if you do a bit of research, you'll find that without a bullet or cartridge case to tell, trauma surgeons and coroners alike cannot determine by the wound channel what caliber and weight of bullet made the wound.

    As kleanbore said, with handguns, the net effects are going to depend on the depth & breadth of the wound channel, what was hit, and the psychological and physiological state of the person shot.

    I could go on for pages, but I have work to do today, and the information is out there. If you have specific questions, I will do my best to answer them or point you toward a source that can.
     
  13. MTMilitiaman

    MTMilitiaman Member

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    I disagree with the OP, especially in the context given.

    In the included link, I can only assume that all shots were exchanged with handguns. Handguns are handguns and rifles are rifles, specifically because of certain velocity thresholds that most handguns are unable to obtain. All defensive handgun rounds behave pretty similar, because they all operate below 2000 fps, and they are all designed around the same FBI sponsored tests. Regardless of whether the officer was using a .357 SIG 125 gr at ~1500 fps or a .45 ACP 230 gr at ~800 fps, no real damage due to "hydrostatic shock" can be expected. Both rounds rely completely on the permanent wound channel created by tissue actually displaced by the projectile--only penetration and expansion contribute to the wound.

    Living tissues are amazingly resiliant to these oft touted shock forces produced by high velocity projectiles. While it is impressive to demonstrate this effect shooting full milk jugs and such, it is important to realize that the human body behaves much differently. Our vital structures are far more elastic than the plastic of the milk jug. Consequently, research by Fackler and others shows that impacts below 2000 fps have little or no shock effect on the vast majority of tissues.

    Now, even among rifles, I think the effect of shock on the body has been grossly exaggerated. I've seen too many animals run a decent distance after sustaining high velocity magnum rifle rounds to the chest to rely on the effects of shock. It's nice when it works, but is fickle and unreliable, in my experience. I shot this fat doe once with a 7mm Rem Mag loaded with a 160 gr Partition over a compressed charge of H870, listed in the manual at 3100 fps, at a range of about 30 feet. The round was perfectly placed and at that velocity, shock and fragmentation damage from the front of the projectile coming apart was obvious. The heart was blown bruised and battered from its protective lining, the lungs looked like bloody oatmeal in their entirety, fragments from the front of the round could be found six to eight inches off the track of the projectile. The deer still ran about 40 yards before succumbing. I've also seen the results of a 250 gr Sierra Matchking coming apart on a steep quartering shot on a small doe. My dad had just put together a .338 RUM built around a Rem M700LA and a 30 inch Lilja, which drove this projectile over 3100 fps (chrono'ed). The round hit base on neck, on side, and exited just behind the last rib on the offside. The exit wound looked like it was produced by a chainsaw--a large gash ten inches long and four inches wide, out of which the entire contents on the animals abdomen and most of its chest cavity had been blasted all over the backstop. The deer still ran about 50 yards. It didn't even really have to be field dressed...50 yards.

    Bottom line is that terminal ballistics is as much black magic as science right now. We have some amazing projectiles, and a better diversity of launching platforms than ever. But regardless of all the testing and science, when it comes to predicting the effect of a projectile on a living organism, we just don't have the technology. Killing something is fairly simple and straight forward. But stopping someone relies on a bunch of physiological effects and other factors that can't accurately be predicted or quantified. If someone wants to stay in the fight, and has the mindset to do so, it can be very difficult to take them out of the fight. Prosecute your targets all the way down, until they are no longer a threat. And in my experience, hunting, shock is awesome when it works but not nearly as reliable as penetration through something vital, so I tend to prefer heavy for caliber projectiles, even at relatively mild velocities.
     
  14. denton

    denton Member

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    It's a huge can of worms. I'll start by saying that nobody has a really, fully successful model that predicts bullet success, including me. You can do pretty well with a target made of uniform stuff, like ballistic gel. But when you throw in tough stuff like bones, or airy stuff like lungs, the models don't work so well.

    There are some things that are known, that help.

    When a bullet impacts, energy divides into two main effects. One is the tearing and crushing to form a permanent wound cavity. The other is temporary elastic stretching of the surrounding tissue.

    Slow bullets spend practically all their energy on the permanent wound cavity. Death follows quickly if the wound cavity intersects a large blood vessel, or a blood-rich organ such as the liver or lungs, or, of course the heart. For slow bullets, Kranz's Law roughly applies: Wound cavity volume is proportional to kinetic energy.

    Faster bullets divert more energy to temporary elastic stretching, and Kranz's law breaks down.

    The one law that firmly holds is that momentum of the bullet at impact = momentum of the target and bullet after impact. Sadly, I don't think it helps much with the discussion at hand.
     
    Last edited: Oct 18, 2013
  15. Sam1911

    Sam1911 Moderator

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    This is why defensive handgunning has coalesced around the idea of multiple well-aimed shots on target as fast as humanly possible. You don't take a shot and wait to see if it did the trick. You shoot and shoot and shoot until the threat stops being a threat.

    Well that is a very good thing, then! Glad you saw the video!
     
  16. MachIVshooter

    MachIVshooter Member

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    Force and kinetic energy are NOT the same thing. Force is more closely approximated by potential energy, but still not synonymous.

    A certain amount of force is required to accelerate an object at a given rate. Hence force is a calculation of mass and acceleration.

    A certain amount of energy is available/developed when and object is traveling at a given rate. Hence energy is a calculation of mass and velocity.

    Think of it as a coil spring. When the spring is compressed, it has potential energy. If the spring suddenly decompresses, the end that is moving has kinetic energy. If the spring is used to move another object, the rate at which it can accelerate that object is the force.

    Definitely over-simplified, but basically, yes. A bullet's kinetic energy translates to its ability to do work, that work generally being tissue destruction. So while predictable terminal effects are something of a unicorn, one can say with reasonable certainty that a lighter weight expanding projectile traveling at higher velocity is going to create a larger but shallower wound cavity than a heavier, non-expanding bullet at lower velocity if both generate the same amount of KE.
     
    Last edited: Oct 18, 2013
  17. RetiredUSNChief

    RetiredUSNChief Member

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    The problem of relating your experience in hunting (presumably with rifles) with handguns in self-defense is that handguns are not rifles. Most especially those handguns typically carried for self-defense.

    Handguns are inferior firearms compared to the capabilities rifles are able to acheive. The obvious advantage of handguns, however, is that they can be carried about far more conveniently than a rifle. This is the tradeoff people make when they choose to carry a handgun for self-defense.

    Add to that the fact that every handgun has it's advantages and disadvantages compared to other handguns.

    And further add to this the fact that shot placement is absolutely critical in any self-defense scenario.

    AND every person, and every scenario, is different...so one person getting shot one particular way might not react the same way as another person getting shot the same way.


    I used to think it was all about energy transfer, too. But it's not. Energy transfer is just ONE means of evaluating the POTENTIAL any given round has. But it's not the be-all and end-all with respect to bullet performance from a handgun.

    The critical factor is the severity of the actual wound produced for any given shot. This involves a lot of different factors which have to be taken into account holistically. Where the wound is located, damage to organs, amount of bleeding caused, how vital the damaged organs are to continued survival and function are some of the most important factors.

    Yes, mass plays a part in this. And so does bullet diameter, construction, and velocity. But any bullet has to be placed effectively in order to BE effective. And yes, some bullets may be more "forgiving" than others in this respect, within limits. But that's no substitute.
     
  18. IBEWBULL

    IBEWBULL Member

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    I agree with the Chief here.
    There is a "threshold" where HV becomes more useful in the stopping power. I don't know what it is.
    Also the heavy slower moving projectile has more time to transfer energy and is not wasted so much in the pass through scenario. Evident in the 45 Colt working on bear.
    This debate can not be proven either way since each individual and his energy level or adrenalin and frame of mind come into play.
     
  19. denton

    denton Member

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    That's absolutely true.

    I don't see how that explanation works.

    Start with F=MA. Integral (MA)=MV=momentum. Integral MV=1/2MV^2=kinetic energy. If mass is a constant, which it often is, then if you know force as a function of time, you know momentum and you know kinetic energy. That's how they are hooked up. Or you can do derivatives and move the other way on the chain.

    So one relationship that does hold is that when a bullet strikes a target, the bullet loses speed. The rate at which it is losing speed and momentum determines how much force it exerts on the target. The bullet continues to penetrate the target until it has shed enough momentum that it can no longer exert enough force to cause the target material to fail.
     
  20. Stress_Test

    Stress_Test Member

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    It's all a big crap shoot (heh).

    Some people take a .45 through the chest and walk to the hospital, and go home a week later.

    Some people take a .22 LR to the chest and drop dead.

    Me, I just want something that will make the 12-inch minimum penetration with a comfortable margin, and don't worry about the rest.
     
  21. Black Butte

    Black Butte Member

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    Each handgun can be viewed as a tool, and what's important is having the right tool for the job at hand.
     
  22. RetiredUSNChief

    RetiredUSNChief Member

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    Absolutely. And it's (correct example of usage, thank you!) also important to realize that there are multiple suitable tools perfectly suited for the job at hand, provided they're used properly.

    :neener:
     
  23. JRWhit

    JRWhit Member

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    According to the info I read,yes
     
  24. JRWhit

    JRWhit Member

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    No disagreements here, I have no solid position in this, just open for discussion.

    However, my train of thought here is not which design and weight is better for a one shot end to a threatening situation, but would one combination offer a longer window of time for which a target is stunned or fatigued due to effects on surrounding body tissue? Sort of like the difference of shooting a 50bmg,one with a muzzle break and one without. Due to the pressure on the body from the directed shock wave of the muzzle break, the effects on the body can be quite dampening to an untrained shooter vs shooting the same rifle without a muzzle break. It is the fraction of a second hesitation caused by the pressure felt throughout the body that I would perceive to be an advantage in a defensive situation, if it exists within higher velocity rounds.
    Two rounds to compare: 175gn 40cal critical duty vs 125gn .357 magnum critical defense. Looking at gel tests, both loads are designed for similar penetration depth. The 40 cal rests at 15.75 in, The .357 rests at 16.5in. The effects on the surrounding media outside of the wound channel, are more exaggerated with the .357, this is where I question If that would have the more stunning effect, stressing muscle and tissue further from the POI , and causing a slight longer delay in the targets motor skill. The reason This all comes to mind, in watching the video The officer sure could have used a few extra split seconds or even milliseconds.
    Also noticed in a different gel test: A 9mm +p Critical duty 115gn offering Nearly identical penetration to the .357 magnum, Had a far less effect on the surrounding media than the 40cal. showing that it cant just be a little faster.
    My point of intrigue in this is rather it would be more likely,not guaranteed, that the shock felt from the .357 would be more of an immediate mind changer than the .40cal? Or even offer that split second of hesitation giving a defensive shooter a greater chance of survival, giving the fact that in a defensive shooting situation, your objective is not specifically to kill and attacker, it is to stop them from fatally harming you?
     
    Last edited: Oct 19, 2013
  25. MachIVshooter

    MachIVshooter Member

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    Again, JR, different people will react very differently to be shot with the same round in the same place. It depends on myriad factors.

    People have dropped instantly with a non-fatal wound from small caliber handguns, but also soldiers have continued to fight, not even realizing the had a rifle bullet hole in them for some time.

    The person's own physical and mental state, the specific parts hit, the nature of the situation (relaxed, or pumped full of adrenaline?) are going to matter a whole lot more than the cartridge/bullet.
     
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