List of Common Misconceptions

Discussion in 'Off Topic' started by Ed Hardy, Feb 7, 2012.

  1. hal

    hal itchy and cold feet hal

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    Actually, Adama, this myth rises from a stance bearing less common sense than the so-called hydrostatic shock theory. It rises from the misconception that a bullet inflicts damage only due to its speed. A bullet, or any other projectile, inflicts damage due to the mechanical energy that it carries, related to both the speed and the mass it has.

    The hydrostatic shock is neither a theory nor a hallucination, Adama. It's a physical factor comprised in any mechanical dispersion phenomena, where liquids or liquid-based substances are the trasmitting media. But regarding ballistics, it's dependant on the situational generality in order to turn out a significant factor of wound mechanics, or not. However there are not many opportunities to poll around survivors of shot wounds (not because there are not many survivors but because they don't give a damn about wound ballistics at the moment they get shot), there is anyway a significant chance of study in corpses. Forensics have a significant interest in wound ballistics.

    Yes, there are unsustained claims of advocates of light calibers that say that hydrostatic shock empowers the ballistics of a small round and therefore they're useful for combat or something, you pick the claim. And they're generally wrong, cause actually hydrostatic shock is noticed with high energy ammunition, most likely mid- to big-calibered rounds of the highest mass threshold in their respective categories, and rounds from high powered rifles. Hydrostatic shock, is present in each and every gunshot and gun wound, but it's measurably significant according to the whole of the factors involving the event, such as shot distance, caliber, bullet impact mechanics, bullet speed at the impact point, bullet weight, target resistance, angle of impact, and the breaking/penetration ratio. All of them are involved in the absortion of the mechanical energy of the projectile, which is in the end the prime factor of wound ballistics.

    Now, this "remote wounding" doesn't involve things like breaking a bone in the leg when getting shot near the collar bone. Most likely, it involves the chance of things like injuring the brachial plexus when getting shot in the lower chest, or even in the abdomen. It will essentially depend on the intensity of shockwaves dispersed into the body, not easily defined the latter just on a mention of caliber. But, again, on the whole situational generality of the event. This "remote wounding" is generally noticed with the use of high-energy ammunition at medium or short range.

    In a sideline, mechanical wave dispersion is so a reality that this is the reason that however feasible it is to shoot a firearm when being underwater, it is generally unwise. When Glock released a pistol model that can be shot underwater, said feature was intended as a last-resort option, not as a mainstream application. Cause for one, being water a more dense media than air, if the shooter has the head submersed as well at the moment of shooting, he's likely to get deaf because of the ballistic crack. And for the other, one of the first testers of this type of application was peeing with blood a couple of hours later, and taken to the hospital to discover kidney injure due to the mechanical vibrations of the ballistic crack. This same type of mechanical dispersion can be detected throughout the human body, but as I said, its effects will be dependant on the general factors.
     
  2. weegie

    weegie Mobile Deity

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    In my experience hunting, energy.... velocity x velocity x grains divided by 450240 and a projectile staying within the confines [thus releasing all of it's energy] is the most successful, deer sized game can be dropped instantly quite easily with a fast lightweight round like a .222 as long as it is landed somewhere close to a nerve center [neck and head]...where I think the hydrostatic shock comes to play, anywhere not near a nerve center, and they will run away and die a slow lingering death because it doesn't have the energy, penetration and frontal area to cause enough tissue and structural disruption.

    According to my Police sister, the 9mm Glock handgun projectiles they use which are a slow but still quite heavy, and designed to fragment on contact thus cause the most amount of arterial and muscular damage to disable baddies, but are unlikely to kill without landing a lucky shot in the head, neck and upper chest, they are trained to aim for the torso, which is where most of them land along with the upper legs etc.

    Mythbusters tests they did into a pool were very interesting where the heaviest and slowest [12Ga with solid slugs] managed to penetrate non-compressable water the best, that Barrett 50 cal sure made an impressive splash though.
     
  3. hal

    hal itchy and cold feet hal

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    Essentially, weegie, taking the hydrostatic shock concept to the field, the true notable effects will arise when nerves are involved in the vicinity of the shot wound. Of course other bodily structures will perceive and perhaps be affected, but with a minimal consequence if compared to the nerve tissues. The example I posted about a shooter being affected in the kidneys, I clarify it obviously involved dissipating the whole ballistic crack in a media much denser than air, and I recall he was shooting holding the handgun at waist level. That was almost asking for the issue. It must be a different situation to shoot the person and then see how much of the shockwave is disseminated in the direction of the kidneys, and also see a factual effect on the organs.

    Well, I'd challenge the statement that those rounds don't kill unless a solid hit in critically vital points is placed, weegie, but anyway I'm not gonna travel just to attest so :p However, lemme point out that one prime reason why law enforcement uses expansive or pre-fragmented ammunition is avoiding over-penetration.

    Those examples are very interesting indeed, but they only allow to watch one out of the two inflicting effects of projectiles: the penetrating effect. In water, the other inflicting effect, the breaking effect, is very hard to watch. That's why suitable ammunition tests are conducted using gelatins, that try to mimic the mechanical behavior of human soft tissues. This kind of materials allow to study how a bullet penetrates, yaws its trajectory, expands, fragments, etc. I don't wanna sound like I got a problem with the MythBusters, but I always remember that's not reliable experimentation. Just, fun :)
     
  4. LandSurveyor

    LandSurveyor LandSurveyor

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    THANK YOU! I spotted that one myself. :D
    Even the relatively dumbed-down lectures I got on that as an aviation management student explained that correctly. It can easily be explained to anyone with a simple sketch of an airfoil in section.

    I would say that they cleared some popular misconceptions but some of that stuff seems to be simply asserting an opposing view or legend.

    Another example, and one that is not technically over my head: There are extant Viking helmets with horns but they were said to be for ceremonial purposes and not actually used in battle.
     
  5. hal

    hal itchy and cold feet hal

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    Anytime, of course, my friend :) Geez, don't you think that it's deprecable that this sort of mistakes are making it into "the world encyclopaedia"? Speaking of that aviation management course, from the outside I understand that it was not intended to train any form of flight crew, and then I consider that it was a great added value to teach the attendance the basics on areodynamics. If not for a practical purpose, well, "to know about the business", am I right?

    That "misconceived misconception" about the airfoil contradicts half of the books that look back at me from the shelf at my side. Not books with meritocratically chosen authors, conveniently anonymous in the end, but rather authors like Tippens, Serway, Resnick, Halliday, Crane, ... Geez, we all use the same Physics books, written by the same authors, in all the schools worldwide! Most likely, who doesn't understand the basics of lift force, is whoever was trying to straighten a line that was already straight to start with, at Wikipedia.

    I agree, and I add that they seem to be falling for the same pitfalls that generated such misconceptions, only giving them a newer twist. The pitfall is not having a clear understanding about a subject, or following poorly informed notions of a subject.

    Yeah, I think I read about it in a book by Asimov. It seems that the helmets with horns are just a cultural cliché, not true combat garment.
     
  6. Adama D. Brown

    Adama D. Brown Brighthand Reviewer

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    Yeah, but it's usually used as an excuse for claiming that weaker rounds, traveling faster, aren't actually weaker than rounds carrying more muzzle energy, i.e. 9mm versus .45 ACP, or .223 versus .308. Whereas field experience shows that muzzle energy is a fairly good measure of effectiveness when all other things, such as placement, are equal.
     
  7. hal

    hal itchy and cold feet hal

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    Yes, indeed. That term is totally accurate: an excuse. There is the notion under which these "claimers" think that a projectile can simply be accelerated in order to increase wound ballistics, but essentially this allows only measurable increments of speed, and the gain in mechanical energy with these speed increments is prone to follow an asymptote. If you want more punch, well just climb to the next caliber in power, that simple. Cause the gained mechanical energy obtained by increments of speed is actually a low one, while an even small increment in mass, conveys a significant increment in said mechanical energy. To-a-point, where it's just better to "raise" to the next caliber.

    Indeed, muzzle energy is a very good measure of effectiveness, cause it is an indicator of the initial mechanical energy of the bullet. Many other factors constrain it, but it is a good measure.

    BTW the reason why the US adopted the 5.56 mm (0.223) family of calibers, had nothing to do with wound ballistics. It was adopted to conform to the NATO standards. In equality of conditions, of course a 7.62 (0.308) has much more mechanical energy on impact.

    In the firearms users communities, there is a precept of much observation when the factors involving caliber and effectiveness arise: The Hackathorn Hypothesis, and it essentially tries to prove what you say about unreasonable claims. Still odd to be found in online texts, cause it predates the digital era. Let me meddle through my old guns magazines and I'll post a verifiable source.

    The Hackathorn Scenario:
    Let's say that you're stuck in a house where 7 psycho killers armed with Ka-Bar knives are trying to get to you. You are able to get into a hallway that leads to a room in the end. At the entrance of the room, there's two side tables, with enough space in between so you get into the room. On each table, there's an M-1911-A1 pistol, but it happens that one of these two firearms is chambered for 0.45 ACP and the other for 9mm Parabellum. At the side of each, there's a magazine holding 7 rounds of the respective caliber. You only got time to grab one of these guns and its magazine, get into the room, insert the magazine, pull the slider, and aim towards the entrance. The psychos will get inside between lapses of 5 seconds.

    The Hackathorn Dilemma:
    Which gun would you pick? :)

    The Hackathorn Hypothesis:
    If all variables drop down to the same, including but not restricted to, magazine capacity, availability of ammo, gun configuration, gun mechanism, threat distance, threat nature, (and so on), effectiveness of wounds is very related to the chosen caliber.
     
  8. weegie

    weegie Mobile Deity

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    You can challenge it, but the facts are the vast majority shot here by police with Glock 17's survive to become an even bigger strain on the state unfortunately.


    Yes, Mythbusters is fun, they actually did this experiment to test how far you would have to be underwater to not be hit by bullets, seemed like a pretty reliable experiment to me....you think they could have done something better?
     
  9. hal

    hal itchy and cold feet hal

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    Yeah, I know what you mean. Of course it's hard to go against statistics. And one factor I am not willing to challenge, is the specific techniques that law enforcement follow over there to apply the general principle of "neutralizing" a suspect. Over here, it involves a shot in critically vital parts - dead is dead. I understand that at least in Canada, Australia and New Zealand, a law enforcement officer is due to preserve a suspect's life under restrains that in many other countries it would be considered an anti-cop policy. And unfortunately is just the right assertion; after getting shot during acts of felony or crime, let's put the same individual in the same streets where the same cop walks out of service. I got a friend in the Cambridge Police in Canada, he says that by no means has he got a carry permit out of service, yeah excellent policy after i.e. stopping a grocery store rob where the suspect eventually makes it out.

    Yes, but essentially the experiment would have had to be taken out of the hands of the MythBusters, thus losing most of the fun in it. For one, they only consider what they can get around right away, so they constrain their tests to what they could get at the moment.

    i.e. if they could get a .38 Special, that's what they use to determine how far does it get under water. Do you know that there are vast ballistic differences when using a .38 Special revolver with a barrel just 2 in long or less, than with one with a barrel longer than that? Well, it's pretty different and the MythBusters won't stop to consider it, cause they're totally unaware of it. Commonplace with the MythBusters: lack of deep knowledge on a subject.

    But if instead, they got their paws on a .45 Government Model, then they'll talk to the end of the world about military ammo. Like if they could get military grade ammo in the first place. Speaking of military-styled weapons, a hard fact is that military-grade ammunition is not available right away. There are strong limitations for that. A semi-automatic Colt M4 carbine sold in the U.S. to the general public simply cannot shoot 5.56mm NATO ammunition. The chamber/bolt closure threshold is not enough to resist the pressure. Cause actually the ammunition available to the general public is quite low-graded in comparison. So they'll talk about "military rounds" going into water when they're actually testing something else. Same thing if they use a Barret 0.50 cal. rifle, and so on. The only conditions in which they would be able to use military ammo is if they comb the surplus stores looking for ammo so old that it doesn't fit the current military standards anyway (even though it's been originally manufactured for the military). Commonplace with the MythBusters: technical biasing.

    The guys fall in love with the "experiment" and they do one attempt after another (attempts are the individual attempts undergoing an experiment), but they don't measure it, they just watch and draw conclusions. They don't use accoustic rangers or meters in order to determine muzzle velocity or impact velocity. They don't place scaled reticles in their cameras in order to determine depth of maximum impact under water. Even when being able to establish said maximum depth of impact, they don't determine whether a round is still dangerous at such depth, they just say: hey, it got 6 ft deep! IRRC, you're a mechanical engineer; pay a visit to a shooting range where serious people meet, and you're gonna feel just at home :) Accoustic speed meters, Vernier calipers, ammunition charts for range and climb, geez a lot of reliable instrumentation and solid data. Commonplace with the MythBusters: they don't use reliable instrumentation.

    When shooting against water, you already know that skids and ricochets are pretty possible. Do they consider that? No, cause it goes against the point they're trying to make. I dare to say that they even cut it during post-production if it ever happened. Again regarding the maximum depth of impact, they don't determine whether it's dangerous at such depth, they just watch with no further inquiry over effects. Commonplace with the MythBusters: they only see what they wish to see.

    They get guns and describe their "experiment", but they don't state a number of attempts, nor they treat them statistically, cause they lack the proper instrumentation in the first place, not to speak whether they know how to design an experiment. They state a vague hypothesis, that works like an old sock, it fits most people. They don't cross-reference their results, in order to determine critical, uniform and subcomplying thresholds. They don't determine whether there's a difference in shooting against the water on a pool or water at the beach, whether still water or moving water. Commonplace with the MythBusters: they lack a methodology.

    Well I could go on, but I think that all this illustrates the subject enough. Yes, they could have done something much better.
     
  10. weegie

    weegie Mobile Deity

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    hal, buddy, if you did mythbusters, you'd bore the crap out 99.99999% of your audience! ;) They're an entertainment show that had a couple of goofs and redhead who always wore one size too small t-shirts....give em a break bro:D

    I actually still own my own chronograph, haven't used it for years, at one time I would spend hours experimenting with velocities and ballistic efficiency of different projectiles down range, to most this would be inanely boring, as it is to me now that I hardly ever shoot these days.
    Have never belonged to a gun club for the reason that they attract a lot of mouths, plus I like doing my own thing and have access to large area's of rural land though family, so have never had a reason to have to put up with city slickers who become the great white hunters down on the range.

    You speak the truth about mythbusters from an obsessive engineer's point of view, I don't think many would agree on the entertainment value though, plus, I'm envious of those people having such a fun job, BS or no BS, I mean, how entertaining would it have been to have that dude who was a 10th dan blackbelt or whatever, and fancied himself to grab arrows fired at him, one of the funniest things I've ever witnessed, when he finally managed to knock one away after being [theoretically] dead about 20 times, he acted like he'd proved some sort of point and went through all the motions of conquest, it was absolutely hilarious.I actually find their lack of technical knowledge to be rather endearing as they don't really make themselves out to be experts on the subject matter and come across as trying to enlighten themselves along the way.

    You shouldn't take it so seriously hal :)
     

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