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357SIG proving to be an unbelievable manstopper???

Discussion in 'Caliber Corner' started by glock20c10mm, Jan 15, 2010.


  1. glock20c10mm

    glock20c10mm
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    N/Apower,

    The following are the current estimated probabilities of BPW playing a role for humans taking an unobstructed hit to the chest for given pressure wave magantudes:

    BPW Probablility
    500psi = 15%
    700psi = 50%
    1000psi = 75%
    1300psi = 90%

    The probability approaches 100% as BPW continues to increase, but will never really reach 100%. The accuracy in the prediction is roughly 10%.




    And, since I have time right now, and in case you and/or others want to know, here is why bullet fragmentation increases the level of peak ballistic pressure wave -

    If kinetic energy and penetration depth are equal, bullets that fragment create a larger pressure wave than bullets that retain 100% of their mass. This is because the average penetration depth is shorter than the maximum penetration depth. Recall that the average force with no mass loss is given by [COC06c]

    Fave = E/d,

    where E is the kinetic energy and d is the maximum penetration depth.

    If we consider the case of a bullet with some fraction, f, of mass lost to fragmentation, the fraction of retained mass is (1-f) and the average force is then given by

    Fave = (1-f)E/d + f E/df,

    where df is depth of the center of mass of the bullet fragments. In other words, df is the average penetration depth of the fragments. Most fragments do not penetrate as deeply as the maximum penetration depth d, so that the average fragment penetration depth df can be expressed as a fraction of the maximum penetration depth

    df = d/k,

    where k is greater than 1. Consequently, the average force becomes,

    Fave = (1-f)E/d + f k E/d.

    This can be rewritten as

    Fave = [1 + f (k-1)]E/d.

    So we see that the enhancement factor for the average force is [1 + f(k – 1)], where f is the fraction of lost mass, and k describes the relative penetration depth of the mass lost by fragmentation. If the mass lost by fragmentation penetrates ½ of the maximum penetration depth on average, k = 2, and the enhancement factor for the average force is (1+f). In other words, a 40% loss of mass increases the average force (and thus the pressure wave) by 40%.

    If the mass lost by fragmentation penetrates ⅓ of the maximum penetration depth on average, k = 3, and the enhancement factor for the average force is (1+2f). In other words, a 40% loss of mass increases the average force (and thus the pressure wave) by 80%.

    Consequently, bullets that fragment can create larger pressure waves than bullets that do not fragment but have the same kinetic energy and penetration depth. Most fragmenting bullets have an average fragment penetration depth of ⅓ to ½ of their maximum penetration depth, so that the pressure wave enhancement factor is between (1+f) and (1+2f).

    In other words, a bullet which loses 10% of its original mass has a BPW 10-20% larger than one which retains 100% of its original mass. Likewise , a bullet which loses 30% of its original mass to fragmentation has a BPW 30-60% larger than one which retains 100% of its original mass.



    Good Shooting,
    Craig
     

    Wanna kill these ads? We can help!
  2. N/Apower

    N/Apower
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    I skimmed his paper when I first saw it, saw that there was a sample size of 10, noted that he included no real data, and threw it out as unacceptable work based on lack of data/information. It would have gotten an "F" in any intermediate college class he chose to turn it during.

    When you asked your question, I half-heartedly went looking for it, and didn't find it, and didn't worry about it.

    The numbers above would have you believe that the answer to the problem is the shotgun loaded with bird-shot at close range. However, real-world use of this proves it's fallacy.

    On the same hand, it would make one think that hard-cast solids are horrible bullets to use on nasty animals like cape buffalo, etc--yet we know that this is not the case.

    Sure, BPW exists, but what does it DO? Whatever it does (or doesn't) do, it's mighty un-predictable. I would much rather choose my tools based on something predictable, like penetration and expansion.

    Given the numbers/percentages of probability of BPW, there is a lot wrong with it if you review some OIS's and look at how people kept trucking after multiple shots.

    This sticky from this forum shows as much.
    http://www.fbi.gov/publications/leb/2004/oct2004/oct04leb.htm#page_15

    You can talk about BPW all you want, throw all the equations out there you want, etc. but that doesn't make it any more effective.
     

    #382 N/Apower, Feb 13, 2010
    Last edited: Feb 13, 2010
  3. unit1069

    unit1069
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    If you've read Courtney's work you know he has stated clearly that for self-defense rounds penetration, expansion, accuracy, etc ... are perquisites before any BPW consideration is taken into account.

    It truly amazes me how many GT members come to the many BPW threads, begin criticizing BPW theory, and inexplicably hold the incorrect notion that any BPW advocate has asserted BPW is more important than the perquisite factors everyone agrees are of primary importance.
     
  4. KenB22

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    OK Batman. Whatever you say. You have your Pulitzer prize winning story now: The FBI is letting innocent agents die because they are too cheap and uncaring to buy the ammunition that you and everyone with half a brain knows is clearly superior in stopping BG's. I say go for it. I'll set up the meeting with Dan Rather. You can be famous and save lives at the same time. Isn't that what a Batman does??
     
  5. glock20c10mm

    glock20c10mm
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    It appears skimming is all you're capable of, clearly explaining you lack of knowledge/understanding of anything you've commented on in this thread thus far. It's no wonder everything you question is such a far reach for you to understand.

    And again, not to rush you, but I did ask you specific questions in my post #376 you haven't answered. I'm expecting to hear from you on them unless you're simply acknowledging you were wrong by ignoring them.

    I've offered you a wealth of information directly pertaining to much of your misunderstanding. There's more but I feel you have enough to digest at one time. But since skimming seems to be all you're capable of it seems I may have wasted my time.

    And on top of all that you've done nothing but skim Dr. Courntey's original work (I have to assume at this point you haven't a clue he's furthered his studies) and yet have the audacity as you claim above to make such uneducated statements as; "The numbers above would have you believe that the answer to the problem is the shotgun loaded with bird-shot at close range." To say/believe anything that far off base shows you are void of any intelligent knowledge reguarding Dr. Courtney's theory of BPW, as has been recently pointed out to you already by at least 3 other GT members.

    Oh, and again, since skimming is your trade signature I should remention - not to rush you, but I did ask you specific questions in my post #376 you haven't answered. I'm expecting to hear from you on them unless you're simply acknowledging you were wrong by ignoring them.

    As for that link you posted which I've read more than once over the years now, please point out what it claimed toward BPW being a falsehood (I don't mean directly, indirectly is fine). I'm assuming you're mostly leaning toward the one-shot-stop stuff? Help us out here. The charts showing death certianly don't tell us anything toward temporary incapactitation. Nor does the literature itself which I read. Please show me what I clearly must have missed.

    And again, since you're a self-admitted skimmer and I have no way of knowing where you'll start reading again, you should know - I did ask you specific questions in my post #376 you haven't answered. I'm expecting to hear from you on them unless you're simply acknowledging you were wrong by ignoring them.


    Hopefully the next time you post back it will show that you know what you're talking about as you now have the info to do so. How anyone can skim anything and come away believing they understand the full content of what was discussed is far beyond my comprehension! Arent' you the one who claimed they work in/around ICUs???

    I'm surprised uz2bUSMC put up with you as long as he did! His patience generally don't extend that far. Maybe he thinks there's hope for you. Well, lets all hope there is. Then there's KenB22... :faint: Let's hope he's learning now too. :whistling:



    Are we clear? :director:

    Craig :thumbsup:




    :popcorn:
     
  6. glock20c10mm

    glock20c10mm
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    Why do you presume everyone with half a brain knows???

    Would you think it wise for all FBI agents to carry 10mm Auto???

    You do realize they have long guns too, right???

    You do realize many agents limit themselves to the bare minimum required tactical practice and many of them wouldn't consider themselves shooters, right???

    You do realize the vast majority of FBI agents don't get the same training as Navy Seals, right???

    You do realize a number of agencies in some departments have dumped 180gr 40S&W loads in favor of much faster and lighter 155gr 40S&W loads, right???

    You do realize the ammo companies know they still have to come up with the lowest bid for ammo while simply meeting the FBI's basic list of requirements, right???

    You do realize not all federal agencies carry the same ammo, right? Does the Secret Service carrying 357SIGs know something the FBI doesn't, or do you presume the Secret Service to be stupid because the FBI already knows what's best???

    Can you explain why Winchester says there is a cult following to their 9mm 127gr +P+ load among LE???

    You do realize many LE depts have ammo choosen for them by some bean counter who has an office window with a view that could care less what ammo they shoot, right???

    You do realize there are LE depts carrying Federal EFMJ, right??? (That's a VERY POOR carry choice if you didn't know!)


    I could go on, but I'm quite sure you're lost already.



    Good Shooting,
    Craig
     
    #386 glock20c10mm, Feb 13, 2010
    Last edited: Feb 13, 2010
  7. N/Apower

    N/Apower
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    See below.
     
    #387 N/Apower, Feb 13, 2010
    Last edited: Feb 13, 2010
  8. N/Apower

    N/Apower
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    Questions answered.
     
  9. N/Apower

    N/Apower
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    In red.
     
  10. KenB22

    KenB22
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    That's certainly what you and your friends think. Everyone who disagrees with you and your buddies is called stupid or ignorant or some variation thereof. Everyone who agrees with you is called smart. Want me to cite the post numbers of everyone who has been insulted because they don't agree with the theory?
     
  11. glock20c10mm

    glock20c10mm
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    Because brain injury does not necessarily mean brain damage.
    At this point for some I suppose there is truth in what you say about proving and disproving. Until someone does a more definitive study (like Dr. Courtney's but with a larger data set) for all to see who haven't seen it on their own I guess some people will be in the dark so to speak. A more definitive study also demonstrating more levels of BPW.
    You mean except for Dr. Courtney's study?
    Again, small data set or not, we do still have Dr. Courtney's study with lots of supporting evidence. More details and refined details would be nice, but we do have reasonably solid data to start out with.
    Not so much when animals are used for the testing which they have been so far.
    No it wasn't implied, or if it was I missed it. I don't know of anyone around here that supports the BPW theory in the sense they expect results 100% of the time.
    No.
    Permanent wound volume, blood volume loss, expansion, penetration, and crushed tissue are all a science of grays. Not on whether or not they probably will happen, but to what extent, shooting to shooting.
    True but beside the point. I was point out a round that does penetrate far enough but was still generally labeled as a failure.
    Right, most LE have left the various 115gr loads for heavier counterparts. Maybe it's just because you haven't been around here in caliber corner long enough yet, but there's been plenty discussed by LE and hunters on the 357SIG being clearly superior overall in terms of incapacitation over 9mm.
    Interesting way of looking at it. (That was meant in a positive way.)
    The data was young enough that the bullets in question were Hydra-Shoks.
     
  12. uz2bUSMC

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    Riiiight, the FBI is the only ones who qualify as law enforcemnt. I see, so all the times you mentioned government agencies or law enforcement... you actually meant FBI. I'm sorry, I didn't realize I was supposed to read your mind. Maybe instead of spellchecking your post you should take time, instead, to make sure they make sense.

    Little hint there are other agencies besides the FBI that belong to the government. There are other agencies that put down bad guys besides the FBI... is any of this starting to click, Robin?

    Now read your posts below ( a few times), then your quote above so you can better understand your own nonsense.


    Did you know that the military puts down bad guys? Do you know what is loaded in their 9mm's? It ball ammo. If the military cared more about their troops than mission accomplishment their would be less restrictive ROE's. You know anything about that, Ken?
     
  13. glock20c10mm

    glock20c10mm
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    Not with all of them. Where most Border Patrol Agents work out here is in the middle of nowhere. Either way, over penetration is a myth and the majority of LE that carry 40S&W still carry 180gr.
    I don't believe we can assume to know what the heads of 99.999% of all divisions carry. Beside that, there are some that carry 45. At the end of the day I don't believe most heads of the division have any clue why they should carry any ammo over other ammo.
    I don't know ammo by those numbers. Who manufactures it?
    Not if the 115s can't be relied upon for proper penetration depth.
    Who knows what specific guidelines they were given in choosing ammo. Maybe it had to be the cheapest premium ammo. Maybe they really are getting what they should for their risk assessments. I'm not aware that Ranger T is all the expensive anyway, if at all. It's the Ranger Bonded loads that cost the big bucks by comparison. Either way they aren't representative for the 1000s of LE depts across the nation.

    Notice your coments are beyond the point I was making to KenB22 though. Otherwise, thoughtful comentary none-the-less.
     
    #393 glock20c10mm, Feb 13, 2010
    Last edited: Feb 13, 2010
  14. Mrs_Esterhouse

    Mrs_Esterhouse
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    Just a quick point for clarification. The US military only uses ball ammo because the Geneva convention bans hollow point ammunition. Unless we withdraw from that treaty, we will be shooting ball ammo for decades to come.
     
  15. uz2bUSMC

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    The point is that other things dictate the choices made.

    And it's the HAGUE convention, not Geneva.
     
  16. glock20c10mm

    glock20c10mm
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    Hey Bones13 :wavey: I didn't forget about you, just took time to get back to you. Better late than never. :supergrin:
    Unreliable doesn't always mean unexpected most of the time.
    True.
    The only way I can see it to mean is that a BG or animal was forced for some reason to give up their attack.
    I can see where it could have been taken that way, but what was meant is explained in Dr. Courtney's write up of the deer study. And what you said wasn't it.
    That's honest enough and fair enough for me.
    Very true! But my point was based on the ammo they carry rating very low in terms of peak BPW.
    I'm with ya on all that.
     
  17. glock20c10mm

    glock20c10mm
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    Not at all.
    Not always. Usually we give you benefit of the doubt at first. Then, if you don't listen to reason (not our opinoin but reason toward what has nothing to do with out opinion) you get called stupid or ignorant or some variation thereof. Remember, just because you spell well doesn't mean you're smart in what you're talking about.
    Not always. Remember the guy uz2bUSMC likes when he posts some posts and not others. Some we think are smart sometimes and stupid, dumb, or some variation thereof others.
    It's not about whether or not you agree with "the theory". It's whether you can debate your side intelligently or not. You can't. Sorry. Believe me, I wish it could be different. You my friend should be asking questions about what you clearly don't understand and we've been gracious enough to point out to you so that you can make an intelligent argument against "us". As it stands, it's clear you don't have enough info to know if you should go along with the theory or not.

    And then to argue someones grammer. :faint: I know a guy who can't spell worth anything, but he'll beat my ass in a game of chess everytime! :fist:



    Good Shooting,
    Craig :cheers:
     
  18. N/Apower

    N/Apower
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    True enough, and I was not responding on behalf of KenB22, but with thoughts of my own.
     
    #398 N/Apower, Feb 13, 2010
    Last edited: Feb 13, 2010
  19. uz2bUSMC

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    Pretty sure .357 sig (as he has posted on here), also pretty sure he handles it well too (as I was told). I think his wife digs the .357sig aswell.
     
  20. uz2bUSMC

    uz2bUSMC
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    N/Apower,

    I read half of that link you posted the other night (so far), and I am going to finish it soon (work is keeping me busy this weekend). I have not seen that before, it is interesting, thanks for sharing it.