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"It's not good to lie to people, dude."

It's not good to call people liars without all the facts either.

Normally, I would agree that a direct hit, square on, from 1 km, in the head from .50 cal probably would kill anyone no matter what kind armor they were wearing, but it's wrong to call him a liar unless you know all the facts. First of all, he was guessing about how far it came from ("assumed to have been fired from about 1km away"), second we don't know the angle of impact. A graze could have just about zero energy transferred. Finally, we don't know if the round had already impacted something on the way (reducing the energy greatly.) It's also possible the round could have been a fizzle too.

Edited by StellarRat
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"It's not good to lie to people, dude."

It's not good to call people liars without all the facts either.

Normally, I would agree that a direct hit, square on, from 1 km, in the head from .50 cal probably would kill anyone no matter what kind armor they were wearing, but it's wrong to call him a liar unless you know all the facts. First of all, he was guessing about how far it came from ("assumed to have been fired from about 1km away"), second we don't know the angle of impact. A graze could have just about zero energy transferred. Finally, we don't know if the round had already impacted something on the way (reducing the energy greatly.) It's also possible the round could have been a fizzle too.

Echo summoned me for this thread(I'm a gunsmith and ballistician, the neuroscientist to Echo's neurosurgeon, if you will). I live and breathe this shit.

I'll run these figures assuming Barret's .50BMG data(velocity, weight, BC, etc.) are correct to start with. Finding reliable data for velocity out of an M2 or DShK is nigh impossible(and I don't have one), so I'll estimate from minimums(M82CQ with a 20" barrel).

Round is 661gr with a BC of .611

Muzzle: 9174ft/lbs @ 2500fps

500yds: 4980ft/lbs @ 1842fps

1000yds 2596ft/lbs @ 1330fps

1500yds: 1533ft/lbs @ 1022fps

2000yds: 1148ft/lbs @ 884fps

So, even assuming that the round came from 2000yds(which is ridiculous, you'd have trouble even seeing a person or small group of people unaided at that range in any kind of practical environment), it's packing almost as much energy as a .223 has at the muzzle. That is a positively massive amount of force(more than it seems like), even on a graze. Modeled as an elastic collision(the most beneficial way to model it for the survival of our hypothetical soldier) using a 3lb helmet and figures for 2000yds we get final (rounded) velocities of:

830fps for the bullet

54fps for the helmet

3lb helmet moving at 54fps = 135ft/lbs of energy imparted to the skull by the helmet. This energy has to go somewhere, and that somewhere is the head and neck of the target. Pulling some figures from another individual calculating bullet/head impacts(specifically JFKs) regarding spinal cord injury

Placing several persons supine with the head resting on bathroom scales resulted in an average range of 8 to 10 lbs. An assumption of 15 to 20 lbs for the head neck mass appears more realistic than 34 lbs. I suspect that mid-neck severed heads weigh about 15 lbs but I do not know of any corner studies confirming this. An accurate estimate of the head neck mass is essential to the calculations.

[using 15 lbs, E=(½ x 15)(1.8)2 = 24.3 foot-pounds, using 26.5 lbs, E=(½ x 26.5)(1.8)2 = 43 foot-pounds, using Wilber’s 34 lbs, E=(½ x 34)(1.8)2 = 55.08 foot-pounds required to move the head as seen in the Z film

- http://karws.gso.uri.edu/JFK/Issues_and_evidence/Frontal_shot%28s%29/Tobias_frontal_shots/Head_snap.html The bulk of this text is irrelevant for other reasons(such as calculating how much force was imparted to JFK's head to result in the neck snapping motion and rebound back and to the left), but the math works out and it's a good indicator for how far the head would have had to travel to result in traumatic injury to the spinal cord.

In conclusion, even assuming the helmet DID survive the impact(the angle of incidence was low enough to not be penetrated by the bullet, by some miracle), and assuming that the helmet didn't move against the head during the impact and impart even further force to the skull, the "friend"'s neck would have been snapped, and he would likely have died or been paralyzed for life.

...so yeah, I'm calling bullshit. If you or Echo would like me to calculate energy of the bullet after striking something hard, ricocheting and hitting the target, I can, but the result is largely irrelevant to the issue at hand(it will still be more than double the required amount).

Thank you for your time,

Paul

P.S. - Ammunition seldom "fizzles". And by seldom, I mean "doesn't happen", at least not in the manner described. When ammunition malfunctions, it is typically either due to age and poor storage(in which case it may hangfire due to bad primers, squib due to nonfuctioning powder or just not fire at all due to bad primers again) or due to poor quality control during manufacture (which due to how the machines work, does not result in light charges, but rather no powder or even rarer a double charge, resulting in either a squib or pressure damage respectively).

Edited by Firebeard
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...so yeah, I'm calling bullshit. If you or Echo would like me to calculate energy of the bullet after striking something hard, ricocheting and hitting the target, I can, but the result is largely irrelevant to the issue at hand(it will still be more than double the required amount).

Wow, that was unscientific. Apparently you didn't read the original post. If you'll actually take the time to read it, you'll see that the facts are VERY sparse. That's why he says it was "ASSUMED". If they knew where it came from it wouldn't be "ASSUMED". So they really don't even know where the bullet came from, therefore, your numbers and assumptions are useless. For all we know it could have come from 2 miles away after going through a tree, a concrete block, sandbags, or bouncing off the ground, god knows what, etc... It was obviously not an intentionally aimed shot. Also, I can guarantee you that if the angle of incidence is small enough you can survive even at 100 yards. That's simple physics. Do your calculations for 1 degree of incidence if you don't believe me. We can assume the armor plate is VERY hard too which would definitely tend to deflect another hard object. It could literally just scratch the paint your helmet and go on it's merry way. If you're proposing that .50 cal is always fatal at all ranges and conditions then why didn't they just stop there instead of putting 120mm guns on the M1? Seriously, there simply isn't enough evidence to make any conclusions about someone "lying". Edited by StellarRat
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Wow, that was unscientific. Apparently you didn't read the original post. If you'll actually take the time to read it, you'll see that the facts are VERY sparse. They don't even know where the bullet came from, therefore, your numbers and assumptions are useless.

They don't know how far it was, but had an approximate. So to be safe, I used /twice as far/ as their approximate. Angle is largely irrelevant to this provided it strikes secantially or directly, while a tangential impact will have progressively decreasing levels of energy imparted, excepting that a tangential impact in this case is going to put a hole in that guy's head anyway(even at 2000yds, that bullet has enough energy to hole both sides of the helmet at ANY angle), and even assuming an infinitely strong helmet will exert enough energy rotationally to twist and snap the neck. Of course, the figures above are completely ignoring that the helmet would have been compromised and his head pulped, by assuming an arbitrarily strong helmet.

I tried to give the target every possible advantage, assuming a range twice the estimate, a secantial impact and an infinitely strong helmet and it still results in a fatal impact regardless, either through the helmet being compromised OR through traumatic head and neck injury.

Of course, if the individual actually was telling any manner of truth at all, they would have known that there aren't any "plates" in a helmet, and that anything inside of two miles with a .50 won't be "pretty slow". Being "sparse with details" doesn't count in your favor when you're making blatantly impossible claims and showing massive amounts of ignorance of things you'd be educated on if you were actually in the military.

I did do my calculations for 1 degree of incidence, on the secant. Anything more aggressive than that is going to put a hole in the target's head. Literally anything that strikes the helmet with the full diameter of the bullet at that velocity and energy is going to be almost three times as much as required to snap the neck. If it doesn't strike on the secant, but rather on the tangent, unless it strikes on an absurdly low percentage of the frontal area, it's going to have more than enough energy to again snap the neck(or penetrate the helmet). Lighter rounds are readily deflected by a helmet, but when you're throwing that much around, you're exceeding the amount the spine can handle.

We don't know for sure, but when a person claims "1km away", that means they at probably have an idea of the distance to the contact, even if it is't precise. To give him the benefit of the doubt, I gave it twice the range, which is significantly reduced energy and velocity from 1km(as you can see).

Somebody speaking out of complete ignorance(again, I point to plates in a helmet) is a pretty good sign they're full of crap, especially when they throw in "I saw somebody" as a vagarie, and when people start making such claims, the burden of proof is on them. A more important question might be why you're going so far out of your way to defend somebody who is telling some really tall tales, with really sketchy information.

Edited by Firebeard
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We can assume the armor plate is VERY hard too which would definitely tend to deflect another hard object. It could literally just scratch the paint your helmet and go on it's merry way. If you're proposing that .50 cal is always fatal at all ranges and conditions then why didn't they just stop there instead of putting 120mm guns on the M1? Seriously, there simply isn't enough evidence to make any conclusions about someone "lying".

Helmets are hard, but they're not exactly "armored," and there is no "plate" in combat helmets. They're not made to stop gunfire. They can stop *some* gunfire, but not the sort commonly slung out by infantry weapon systems; if you wanted to armor someone's head against rifle munitions, you'd essentially have to encase the entire head in about an inch and a half of ceramic or mild steel, and this would still only proof them against square-on impacts from one of the numerous .30 caliber cartridges, and there'd still be a surprising degree of muscle, spinal, and brain trauma, even from a round that's utterly dwarfed by the massive .50BMG round. Helmets simply aren't made for that; they'll stop some fragmentation, or low-powered pistol munitions as long as it's coming from a few dozen meters away, but that's about it. They're essentially a lump of plastic with a few sheets of kevlar or ballistic nylon layered in. And the reason that tanks don't merely host .50 cals is because a tank platform isn't for killing infantry; it's for engaging hostile armor and supporting infantry against other tanks; you can't do that with a .50 cal. They do, however, usually mount one topside to support the coaxial, along with a GMPG for the loader when he goes topside, for example, if the tank is engaged by large numbers of unsupported infantry.

Also, he did do the math for the bare 1 degree of deflection; the rotational torque imparted by a .50BMG round striking a helmet at even twice the range suggested would snap the human neck in several places, resulting in instant and permanent paralysis or death.

The guy's credibility is already damaged by the initial statement on "helmet plates." and pretending like it's an actual thing, even before we consider the preposterous claim.

Edited by EchoFourDelta
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Somebody speaking out of complete ignorance(again, I point to plates in a helmet) is a pretty good sign they're full of crap, especially when they throw in "I saw somebody" as a vagarie, and when people start making such claims, the burden of proof is on them. A more important question might be why you're going so far out of your way to defend somebody who is telling some really tall tales, with really sketchy information.
It's quite possible it simply grazed the side of the guys helmet. Rather than disbelieve the poster why don't you just believe the guy that got hit was extremely lucky due to whatever circumstances? Those things happen all the time in real life. I agree that information provided is very sketchy, too sketchy to draw any conclusions. That's why I said what I said.
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Also, he did do the math for the bare 1 degree of deflection; the rotational torque imparted by a .50BMG round striking a helmet at even twice the range suggested would snap the human neck in several places, resulting in instant and permanent paralysis or death.

Yes, but you're both assuming that the bullet actually fully impacted the helmet rather than "brushed" the helmet i.e. the helmet took the full cross section of bullet. I've done plenty of shooting and have seen some very weird stuff. Like just taking the first layer of bark off a twig. It's really all about the angles. You can find video of people lighting matches with bullet without breaking the match stick.

So, I think nearly ANYTHING is possible under the right circumstances.

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It's quite possible it simply grazed the side of the guys helmet. Rather than disbelieve the poster why don't you just believe the guy that got hit was extremely lucky due to whatever circumstances? Those things happen all the time in real life. I agree that information provided is very sketchy, too sketchy to draw any conclusions. That's why I said what I said.

A hit on a shallow enough tangent to not snap the guy's neck, but still be notable as any kind of "took a hit" is such a tiny area that it's effectively not going to happen. It's about as likely as your "maybe the round fizzled". The line between "hit" and "miss" with .50 cal works out to be under an eighth of an inch. So no, they don't happen "all the time" or even close. Lighter rounds yes, but once you start throwing around that much weigh, the likelihood shrinks to nigh impossibility. The information provided showed quite a lot(an approximate range, that the person claimed he saw it firsthand, the poster's ignorance). So I'm not inclined to give the benefit of the doubt to somebody who doesn't even know what their issued helmet is made of(Echo, care to chime in on if that is taught formally?).

This guy's story is about as likely as a man getting bitten by a great white, while being struck by lightning, twice, in the middle of a tornado. In Idaho. And I've heard way too many similar stories(always from people who can't prove that they even have a military background at all) from others in my line of work.

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There's a matter of practicality and sense, plus a large chunk of reason, StellarRat. The amount of force that a fifty caliber has is just much much more than a helmeted guy is going to survive, unless you want to start assuming truly insane things about the situation. Ballistics are ballistics are ballistics.

Also, you'll note that all versions of the M1 tank carry a M2 .50 in the commanders cupola, in addition to the main gun (which is actually a 105 rifled in the M1, only being upgraded to the 120 smooth-bore for the M1A1 and M1A2). You will kill the absolute hell out of anyone dismounted that you hit with that machine gun, it's designated purpose is to engage light armor, after all.

Generally speaking, the main gun of an Abrams isn't to be used at long range against infantry (I'm full-time Army tanker, note), however, the difference in distance where you can hit someone with a .50 compared to a 5.56 compared to a 7.62 compared to a full size tank round should be obvious. Hint: the bigger rounds go further.

Apologies that I don't have the technical background that EchoFourDelta or Firebeard do, but long-story short, they're completely accurate.

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Helmet plates:

http://www.scribd.com/doc/94629791/Ops-Core-SLAAP-Plate-by-Velocity-Systems

I'm not saying happens all the time in the scope of one persons military career. I mean taking into account entire wars, etc... there are all kinds of stories about survival that are just amazing. I already posted one where the guy survived an RPG to the stomach. Isn't that proof enough? I did say, "extremely lucky"...no? My best friend works in the ER, you wouldn't believe some of things people survive that should by alrights have killed them outright. None of you believe that people get grazed by bullets all the time? I've read plenty of accounts of people actually having holes in their clothes, but the bullet missed the their body.

Here's a guy getting hit by a .50 cal ricochet in the earmuff:

I am by no means saying that I would expect anyone to survive a normal direct hit to the head from a .50 cal. I'm saying an "abnormal" set of circumstances might lead to someone surviving possibly with very little injury, therefore, I'm giving the guy the benefit of the doubt.

Edited by StellarRat
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Those are made for 7.62 x 39 caliber, 123 gr., and they're not military issue for any infantry forces, also, earmuffs aren't secure to your head by a snug set of foam inserts and nylon webbing and straps. Helmets are. Also, one of these aftermarket plates would only be useful for the direct impact we talked about (again, by a much smaller round), not the sidelong or grazing impact that would produce the aforementioned rotational torque. Those plates are also only compatible with helmets made by that manufacturer; these are obviously not MICH, ACH, LWH, or PASGT systems.

Edited by EchoFourDelta
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You can give the guy the benefit of the doubt, but that would make you a fool. People get grazed by bullets all the time and live. People get grazed in the helmet by bullets on occasion, and live. But those are small caliber bullets. The amount of energy imparted on the helmet at a 1deg angle of incidence, from 2000 yds, by a .50 cal is just shy of the same energy putting the muzzle of M16 up against the side of the helmet(at 90deg incidence) and pulling the trigger. It's not that the round was a "near miss" that's the problem. It's that the round supposedly hit with enough energy to result in "a stiff neck", but didn't kill him. The window between the two, as I've explained above, is less likely than me seeing Echo in a dress. If it hits the head, it's going to have enough energy to kill. If it misses, that's not a hit. Period.

Ricochets straight backward that strike shooters are surprisingly common(typically the result of a range that's way too leaded up to be safe, and poor berm design, I've been hit by several in indoor ranges and refuse to shoot in them anymore because of it, that shit stings like a motherfucker), and lose energy rapidly. Ricochets that hit anything else are extremely uncommon. Unless he was shooting a fifty, on a square range, the likelihood of said hit remains pretty much nil(and if the poster had any measure of honesty, would have mentioned that it was a ricochet). So he's either outright lying, or (on an extreme longshot) he's stretching the truth intentionally(still lying in most people's books).

The odds are so far against it that no sane person ought to consider him anything less than a liar.

EDIT TO ADD:

Which is more likely, that he saw somebody survive something this unlikely, or that he is, in fact, full of shit.?

Edited by Firebeard
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Well, I guess we'll never know for sure unless 4Aces gets back on here with more details. Of course, since you've all called him a liar he may not be so inclined. Or it could have been a tall tale and we'll not see him back. Until then, I'll give him the benefit of the doubt. I just don't think there is enough detail to draw any conclusions. It could very well have been a ricochet. Obviously, since the guy had an armored helmet of some kind and it was .50 round, it sounds like it's possible it was an accidental hit of some kind. As far as I know none of the current enemies of NATO troops are fielding .50 cal weapons as a matter of course. The closet thing I can of would be the Russian 12.7 mm and 14.5 mm MGs.

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Well, I guess we'll never know for sure unless 4Aces gets back on here with more details. Of course, since you've all called him a liar he may not be so inclined. Or it could have been a tall tale and we'll not see him back. Until then, I'll give him the benefit of the doubt. I just don't think there is enough detail to draw any conclusions. It could very well have been a ricochet. Obviously, since the guy had an armored helmet of some kind and it was .50 round, it sounds like it's possible it was an accidental hit of some kind. As far as I know none of the current enemies of NATO troops are fielding .50 cal weapons as a matter of course. The closet thing I can of would be the Russian 12.7 mm and 14.5 mm MGs.

Helmets are spall protection, (the best ones do meet level III-A, but hits by anything meatier than shrapnel or very light handgun rounds at shallow angles of incidence will generally result in traumatic neck injuries or worse).

The 12.7x108 round fired by the DShK and similar deliver comparable energy to the .50 BMG, and for all intents and purposes somebody taking fire from them won't be able to tell them apart without being familiar with the sounds of both weapons firing. Somebody over there would be able to distinguish the difference, but for our purposes the difference is academic(they throw comparable velocities and energy).

In addition, captured/loaned M2s are surprisingly available in that part of the world(a friend sent me back some pics from a-stan I'd be happy to link of about a dozen older model M2s rusting away in a scrap pile). It's obviously not as common as leftover Warsaw Pact hardware, but they are floating around.

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