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In my Story currently there are magnetic revolvers only usable by those with enhanced strength, but I need to know what the impact of a bullet travelling faster than average because I know that there is an aspect of stopping power with the shot, so I want to know how much damage could this do should it hit a human in the center of the rib cage.

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This question asks for hard science. All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See the tag description for more information.

closed as off-topic by Burki, Mołot, Youstay Igo, MozerShmozer, James Feb 17 '17 at 18:05

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "This question does not appear to be about worldbuilding, within the scope defined in the help center." – Burki, Mołot, Youstay Igo, MozerShmozer, James
If this question can be reworded to fit the rules in the help center, please edit the question.

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    $\begingroup$ I don't see how this is about worldbuilding. But as for your question: the target would be much deader than when a normal .50-calier bullet hit him in the chest, which, by the way, would still be dead enough for all practical purposes. $\endgroup$ – Burki Feb 17 '17 at 16:37
  • $\begingroup$ then what would it be? it doesnt seem to fit anywhere else? $\endgroup$ – Fox-Chan Feb 17 '17 at 16:42
  • $\begingroup$ I just need a description of what would happen $\endgroup$ – Fox-Chan Feb 17 '17 at 16:45
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    $\begingroup$ First: there are some differences in the effect depending on the shape and the composition of the bullet. Then on the exact location where the bullet hits. Does it hit a bone or soft tissue? A torpedo-shaped, hard and not brittle bullet might actually just pas through the target. A fragmenting or deforming bullet will create an exit crater, taking large amounts of victim with you. You may want to google the caliber in question, and different types of bullets, you might find some (nasty) insights. $\endgroup$ – Burki Feb 17 '17 at 16:47
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    $\begingroup$ @Fox-Chan the fact that you can't find a better place to ask something does not mean it is worldbuilding. This site is not a "catch all" for questions you have nowhere to ask. $\endgroup$ – Mołot Feb 17 '17 at 17:26
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Doing some back of the envelope math, 4800 km/hr is equivalent to 1333.333 m/s. This makes it a High Velocity (but not Hypervelocity) round. This means in terms of physics, it is not outside the realm of possibility.

Based on statistics of the Browning Machine Gun Rounds, it's muzzle velocity with some ammunition (647 gr (42 g) Speer) is 928 m/s. Let's assume that everything else constant, your bullet will be about twice as powerful(see note at the end) than this round. The BMG rounds have some pretty serious stopping power (given that the BMG was originally intended as an armored car/tank killer), so what you are going to have with your round is something that can penetrate better.

I like the example of the Barret M82 a 50 cal sniper rifle using these rounds. This gun has been reported to regularly punch through unreinforced walls and kill those on the other side. Basically, your improved round is nothing more than more of a "bunker buster" than the BMG. Probably getting through unreinforced walls (and maybe even creating shrapnel from those it doesn't fully penetrate. I would hate to be in a wooden room hit by these). I will also point out that the Barret M82 is capable of shooting through people. (it also has the distinction of holding the record for the longest sniper kill among US Service men, beaten out by two Canadian records by the McMillan Tac-50, another BMG rifle, and one by the AWM 338, which uses a NATO .338 round).

As to what it would do to a person....someone without body armor would be chunky salsa to a BMG round, so at best your better round would just spread damage a little more (so if hit in the head, a little less of the lower jaw/neck would still be attached, the chunks would be less recognizable as human, etc). Against someone with body armor, more of the damage would be inflicted on the body (most rifle rounds can penetrate basic body armor, and the BMG definitely can as it can go through walls and doors). Your better round is just more capable of penetration and would do more damage to a person.

NOTE ON POWER: Quick kinetic energy calculation, assuming the same mass of round, puts the new round at about 2.064 times the kinetic energy of the original, not 43% as I originally thought.

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  • $\begingroup$ should the (impact) energy not rise with the speed squared? (or however the correct terminology is in english, sorry...) $\endgroup$ – Burki Feb 17 '17 at 16:58
  • $\begingroup$ @Burki yes, that is correct. I was thinking of a different equation. Rewriting that bit. $\endgroup$ – Marshall Tigerus Feb 17 '17 at 17:02
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Rib cage is mostly air

Hitting the rib cage means you hit the victim where the body is the least dense and actually mostly air. Not to say there will not be horrific injuries, but probably less than people assume.

$4800 kph$ is approximately 3 times the velocity of a .50 Action Express fired by a IMI Desert Eagle. Assuming the same dimensions and weight, this means 3 times the inertia, and 9 times the energy (energy squares with the velocity), let us say 10 to make it a nice even number.

By comparison a .50 BMG (heavy machine gun ammunition) also has about 10 times the energy of the .50 Action Express. So your fictional round will be roughly equivalent to taking a heavy machine gun round to the chest.

The main issue here is that since most of the rib cage is air, and air has such a low density, it will not absorb much of the bullet's energy or inertia, and therefore not transfer that to the body.

The entry wound will most likely be small, because at that speed, the bullet will just stamp a hole. What happens at the exit side can probably be tailored to your liking. The exit wound will be larger than the entry. But how much larger depends on what kind of debris the bullet brings — rib, sternum, lung tissue — and what it hits when leaving.

The extreme examples...

Coming and going between ribs, passing a lung.

The air will not soak energy and will also disperse the shock wave. This type of injury can probably be survivable it brought to medical attention. Expect an entry wound the size of the caliber, and an exit wound roughly 2 to 4 times the caliber.

Hitting sternum and spine

This will deform the bullet, hit the aorta, and then rip out a large chunk of the spine. This kind of injury is instantly lethal. The shockwave from when the blood soaks energy will make the aorta splash open like a broken water balloon. A hit to the heart will do something similar. And the rigid obstacle that is the spine will create a cloud of bone debris flying out of the back, at least the size of a fist and upwards.

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  • $\begingroup$ Nice point, hadn't thought that the lungs are, in fact, bags of air. $\endgroup$ – Paul TIKI Feb 17 '17 at 17:20
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If your bullet has a conventional shape, its energy will simply enable it to go through your target's body and maintain a very decent speed after this. So you can probably kill a bunch of people in one shot.

If your bullet has an unconventional shape, it can become funny (except for the target) :

  • a 4800 km/h tennis racket will probably slice you in pieces
  • a bowling bowl will let more of its energy in the rib cage, painting the surrounding in red
  • a phone cabin will transform the target in small parts.

Expect a dead target in all circumstances, anyway...

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This question asks for hard science. All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See the tag description for more information.

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    $\begingroup$ a .50 phone cabin and tennis rack... ? i guess that requires more clarification... $\endgroup$ – Burki Feb 17 '17 at 16:56
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    $\begingroup$ Indeed, I go outside the initial question scope. There was not that much to say regarding a high-speed bullet beside it has more energy... $\endgroup$ – Uriel Feb 17 '17 at 17:06
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As a reference, a Barrett .50 cal sniper rifle has a muzzle velocity of 2800 feet per second (853 meters per second). Your proposed round travels at 4374 feet per second (1300 meters per second). The amount of energy is 1/2mass times velocity squared. That is a hell of a lot of energy. If you are firing a jacketed slug, it's just going to punch a half inch hole through people and anything behind them. If you have a hollow point, it changes things because the slug deforms as it passes through. Cavitation, fragmentation, bone fragments and such might mean you get a red mist where the target's back used to be along with. There are even nastier rounds that remain solid and then fragment on impact to increase the carnage. In addition there are steel core rounds designed to punch through armor, and moving at those speeds you would have a round that would put a hole in nearly anything.

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