Stopping Power, Overpenetration and Killiness...

[Shroom Man 777]

I think this belongs to SLAM, since killing people is widely considered to be a scientific process.

Anyway, hollowpoint bullets and the like are preferred because of the trauma they give the human body upon entry, they also expand and impart all their force there, and that's fatal.

But if a bullet overpenetrates, that makes the resulting injury more survivable, right?

And...err...is it possible for a person to survive and maintain combat effectiveness after being hit by a .338 Lapua Magnum sniper round?

[drachefly]

I would imagine that depends where they were hit.

I don't think people are going to do much fighting when they've got nice smooth holes poked through their torsos. Not usually, anyway.

But I'm not a ballistics expert, nor a getting shot in the torso expert.

[Azazal]

The big thing with a exit wound form a hollow point it it will be quite large. The person will be bleeding profusely to say the least. So while they may survive the initial wound, the blood loss will get them if they do not receive immediate medial attention.

[Stuart]

I think this belongs to SLAM, since killing people is widely considered to be a scientific process. Anyway, hollowpoint bullets and the like are preferred because of the trauma they give the human body upon entry, they also expand and impart all their force there, and that's fatal. But if a bullet overpenetrates, that makes the resulting injury more survivable, right? And...err...is it possible for a person to survive and maintain combat effectiveness after being hit by a .338 Lapua Magnum sniper round?

Bullet wounds are an art form, not a science. I don't think there's ever been a convincing general theory of bullet wound dynamics, they keep getting invented, get promoted for a while and tehn fade away as teh anomalies get too large.

According to one friend of mine who has a disturbing amount of experience in such things, "Placement is everything. .22 long rifle 5cm to right of left ear is much more effective than .44 magnum 5cm to left of left ear"

[General Zod]

But if a bullet overpenetrates, that makes the resulting injury more survivable, right?

Overpenetration means that the bullets have gone too deep, possibly exiting the body entirely and striking something you don't want them to. This usually isn't a good thing since it's no longer going to be flying stably and will be much more unpredictable.

[Surlethe]

Hollowpoints work because they transfer all their kinetic energy to the body. It has to go somewhere, and so it tears tissue up. Placement is important because some types of tissue, like bones, tear up less easily than other types of tissue, like muscle and organ meat. And if the bullet penetrates through the body, it still has kinetic energy upon exiting. That means it didn't transfer all of its energy to the body, which in turn means it didn't do the maximum possible amount of damage given its placement.

[Majin Gojira]

Aren't they testing Smartbullets now? I remember seeing something about them, they expand in a soft target and flatten against a hard target.

Or something.

[GrandMasterTerwynn]

I think this belongs to SLAM, since killing people is widely considered to be a scientific process.

Anyway, hollowpoint bullets and the like are preferred because of the trauma they give the human body upon entry, they also expand and impart all their force there, and that's fatal.

Yes. And no. JHP rounds meant for use on people are designed to expand, deposit all their energy on-target, and penetrate deep enough to produce a stop, without overpenetrating. It's not necessarily about making the round more deadly. Take a .45 ACP 230 grain JHP at around 900 ft/sec, and a .45 Colt 255 grain Keith SWC (most decidedly not a hollowpoint, or even an expanding round) at around 900 ft/sec. Same caliber, roughly the same ballpark in terms of energy. But one is an effective man-stopper, and the other will penetrate clean through, and kill deer and horse-sized animals.

But if a bullet overpenetrates, that makes the resulting injury more survivable, right?

Depends on the bullet design. A round-nosed bullet will tend to shoulder tissue out of the way, creating a smaller wound-channel. A big, heavy semi wad-cutter with a wide tissue-crushing front end will plow a huge channel straight through tissue. But the answer is usually no, if for the simple reason that you now have twice as many holes to bleed out of than you would've if you'd been shot with a bullet that didn't achieve complete penetration.

[GrandMasterTerwynn]

Hollowpoints work because they transfer all their kinetic energy to the body. It has to go somewhere, and so it tears tissue up.

A punch delivers roughly the same kinetic energy as being shot, and has the advantage of transferring 100% of its kinetic energy to the target. However, punches usually aren't as injurious as gunshots. A hollowpoint, especially a pistol caliber hollowpoint, gets its effectiveness from its ability to create a bigger hole than its FMJ equivalent. For that matter that popular Saturday Night Special cartridge, the .25 Auto will generally stop inside a person and completely deposit all its kinetic energy, and be less injurious to a person than being shot with .45 Auto FMJ rounds which can penetrate through-and-through, but leave much bigger holes.

Placement is important because some types of tissue, like bones, tear up less easily than other types of tissue, like muscle and organ meat. And if the bullet penetrates through the body, it still has kinetic energy upon exiting. That means it didn't transfer all of its energy to the body, which in turn means it didn't do the maximum possible amount of damage given its placement.

A bullet does damage and kills by one of two mechanisms. The first mechanism is by poking or tearing large enough holes in enough of the target's circulatory system that they bleed out and cannot sustain metabolic activity in their brains, resulting in death. The second mechanism is if the bullet disrupts enough of the CNS that a life-sustaining level of neural function cannot be maintained, resulting in death. You can't kill someone any deader than dead. It doesn't really matter to the person being shot if the bullet stays inside, or if it penetrates through-and-through if they bleed out and die as a result of their wound, even though one bullet didn't deliver 100% of its kinetic energy to that person.

[Darwin]

I think this belongs to SLAM, since killing people is widely considered to be a scientific process.

Anyway, hollowpoint bullets and the like are preferred because of the trauma they give the human body upon entry, they also expand and impart all their force there, and that's fatal.

But if a bullet overpenetrates, that makes the resulting injury more survivable, right?

And...err...is it possible for a person to survive and maintain combat effectiveness after being hit by a .338 Lapua Magnum sniper round?

Overpenetration isn't always undesirable. It's frowned upon for police and self-defense work for obvious reasons, but a bullet does its damage through multiple kinds of work:

crushing tissue in the main wound cavity
blood loss
hydraulic trauma
neurological trauma

Focusing on the full energy transfer of nonpenetrating vs penetrating wounds ignores all the other factors that an overpenetrating round excels at.

[The_Saint]

I think this belongs to SLAM, since killing people is widely considered to be a scientific process.

Anyway, hollowpoint bullets and the like are preferred because of the trauma they give the human body upon entry, they also expand and impart all their force there, and that's fatal.

But if a bullet overpenetrates, that makes the resulting injury more survivable, right?

Yes and no.

Modern military ammunition according to the Geneva convention is required to be 'jacketed' so that when shot the injured party won't suffer from lead poisoning (at least this is the basics of the reasoning). Jacketed projectiles will hold together on impact with fleshy objects and, with enough momentum, pass straight through them. This ties in with the surprising fact that modern smaller calibres, 5.56 x 45/5.45 x 39 are not specifically "designed" to kill but to give grievous injury. (This is based on the simple concept that if a soldier is killed it only takes one more soldier to collect his dog tags and bury him, whereas a wounded soldier requires many others to care and transport him.)

Really it's a case of frying pan and fire. A projectile that is designed to fragment will mean you have lots of little bits of metal bouncing around inside your body tearing it apart.
On the other hand a jacketed round will stay in one piece but on it's way through the body will act as a buzz saw (due to spin) cutting everything it touches, it won't get every organ but any organ it meets will need replacement.
A 7mm round will flatten out to about an inch in diameter with jagged edges!!

And...err...is it possible for a person to survive and maintain combat effectiveness after being hit by a .338 Lapua Magnum sniper round?

Survive.. quite possible depending on hit location. It could pass through your side and if it missed any organs then all you'll need is a few wound dressing to plug the holes. Same could be said for almost any calibre though.
Though the people who would be using such a calibre (snipers) are likely to be aiming closer to your face than your guts.

Combat effectiveness is an odd thing. The physical shock of a bullet impact will obviously do damage (that's what we've been discussing) but the psychological impact will vary.. some people go to pieces with a splinter... a soldier in the middle of a battle, high on a adrenaline who's had a bullet go through a fleshy body part (and miss anything vital) might still be ready to keep fighting after the application of some bandages.

[Baal]

Most of the time when there are complaints about overpenetration of rounds and not taking down foes it is for reasons OTHER than the round itself.

Two examples that come to mind are the BlackHawk Down episode in Somalia and the Muslim based insurgency in South East Asia.

In both places troops ran up against opponents who were or are heavily doped up on drugs. This means the target does not feel the pain of the round. So sure they were shot but if the shot doesnt physically disable them (ie destroy important organs or break important bones) the target will continue to fight in the short term or escape long enough to die somewhere else later on.

Another example was the creation of the standard US Army .45 which was created to fight jungle insurgents in the Phillipines. It was found that standard army revolvers didnt have the stopping power when a drugged up rebel with a machette was charging at you. Sure he may die of blood loss 10 minutes later but that doesnt help you when he buries that big ass knife in your chest.

[Adrian Laguna]

Another example was the creation of the standard US Army .45 which was created to fight jungle insurgents in the Phillipines. It was found that standard army revolvers didnt have the stopping power when a drugged up rebel with a machette was charging at you. Sure he may die of blood loss 10 minutes later but that doesnt help you when he buries that big ass knife in your chest.

Machete? The Kris is not a fucking machete.

[Adrian Laguna]

Stupid broken link...

[Napoleon the Clown]

Hollow points are nasty because they increase permenant cavitation, not because they transfer more of their energy to a target. Going off that kind of logic, kevlar should make a round more lethal, not less.


When a FMJ round hits you, there's little deformation of the round. As mentioned, the hole will be smaller than the round itself. How much is based off of the shape of the round. A rounded or pointed round will cause the smallest wound, relative to the size of the round, whereas a flat nose or concave nose will cause a wound that is much closer to the diameter of the round. Flesh is surprisingly elastic.

A hollow point has multiple advantages against flesh over most other rounds. One is that you can have a smaller diameter round, giving you more shots for the same size magazine while still making a big ass hole in the poor bastard you shoot. When a good hollow point hits flesh, it expands. Like so (9mm hollow point, expanded) This will increase the diameter of the round inside the body, causing more permenant cavitation (which is the flesh that goes bye-bye, whereas temporary is where it merely stretches away). The benefits are that you cause more bleeding and disrupt more functions. The shape also causes it to more effectively cause permenant cavitation, as it is by no means aerodynamic at this point.

Of course, shitty ass hollow points don't mushroom too well. This makes them little more, if at all, effective than a FMJ round of the same size.

In any event, shot placement is very important. A 9mm to the spine is a hell of a lot more incapacitating than a .45 shot that fails to perforate any vital organs.


In regards to overpenetration, the issue isn't how much it hurts the "bad guy" as it is what kind of danger it presents to anything behind the target. Depending on how much of the target decides to accompany the round, a full penetration can be more deadly. A 12 gauge deer slug will have little difficulty going through someone completely. And the exit wound will be far larger than the round itself. Compare that to a breaching round, which is unlikely to reach any vital organs based off this test. (Note: linked directly to relevant page) While both rip the hell out of the target, it's much more likely for you to survive if your spleen remains inside you.

Also in regards to penetration level, keep in mind that the most effective swords when it came to killing the person dead were the ones you ran the person through with. The deeper the wound goes, the more likely it is to damage something vital. And failing that, it causes a lot of bleeding.


As far as not only surviving, but being able to keep fighting after getting shot: It really depends on shot placement and how vicious the bastard is. People on PCP have been known to keep trying to fight after getting tasered, maced, shot... The only guarenteed way to stop someone is to make it so they are physically incapable of continuing. If the shot misses the CNS there's an outside possibility of the person remaining concious long enough to make life hell for you. Even if you poke a hole in their heart they have a few seconds (rarely though) before they black out to do something in retaliation. So yeah, it's possible, though highly unlikely.

[Baal]

Another example was the creation of the standard US Army .45 which was created to fight jungle insurgents in the Phillipines. It was found that standard army revolvers didnt have the stopping power when a drugged up rebel with a machette was charging at you. Sure he may die of blood loss 10 minutes later but that doesnt help you when he buries that big ass knife in your chest.

Machete? The Kris is not a fucking machete.

Because when you are a bunch of hillbilly guerilla fighters hopped up on drugs in the jungles around Manila you are going to be running around with a kris.

[Adrian Laguna]

Because when you are a bunch of hillbilly guerilla fighters hopped up on drugs in the jungles around Manila you are going to be running around with a kris.

It wasn't the hillbillies in the jungles around Manila that inspired the US Army to ask for a gun capable of taking down a charging native. It was the Moros, the crazy mother fuckers from southern Mindanao and the Sulu archipelago. And yes, they did run around with krises, which makes them quite a bit more dangerous than if they had a mere machete.

[Connor MacLeod]

Its worth noting that the body, which is composed mostly of water, tends to deal very well with shockwaves (IIRC the speed of sound in human flesh is about that of water.) While it can tear very easily when punctured by high pressure impacts (bullets, knives, etc.) it handles shockwaves rather well (the "temporary cavity" created by the passage of a bullet.) It's only on really really high end bullets that the shockwave might be damaging at all to tissue (stretching or tearing, ,basically.) the permanant caivt,y of course, is the path the bullet takes in the body (whether it tumbles, expands, fragments, or whatever.).

In most rifle bullets, you'll get either fragmenting (the bullet basically explodes into pieces and each one creates a bigger wound chanenl) or the bullet is designed to "tumble" in the wound, basically creating a bigger hole than its diameter might suggest. Few pistol bullets do that, so the next best thing is a hollowpoint (or something like a glazer round.) Though I think you can get tumbling bullet wounds too (but their length to diameter ratio is smaller than with rifle bullets, so the channel won't be much bigger either.)

Even with a hollowpoint, the wound diamater isn't that big (an inch or so would be good.)

I've always liked looking at ]this page because it has useful data on these things and the drawings based on ballistics gel can be kinda useful.

[Sea Skimmer]

Most of the time when there are complaints about overpenetration of rounds and not taking down foes it is for reasons OTHER than the round itself.

The M855 heavy ball ammo was part of the problem. It’s a lead free semi AP round with a steel core. When it hits body armor it works pretty well, the steel tip breaks away from the aluminum core and you get a wide wound channel. However when you hit someone with hardly a shirt on; it may pass clear through. Ironically it was especially prone to doing this at point blank range when its velocity is incredibly high.

At long range, you don’t notice the small wound on the target, because the person who got hit will still bleed out and die, they just aren’t instantly incapacitated. Instant incapacitation hover is critical for close quarters urban or jungle fighting. The older M193 ball used in Vietnam was more reliable at fragmenting and you never did hear of many people complaining about it in that war.

It’s telling that all branches of the US military have finally begun buying a new 77 grain round called Mk262 (because it was first adapted by the USN for SEALs), in response to many complaints of low stopping power and poor ballistic performance in general of M855 fired from the M4. It won’t replace M855, but the orders keep going up.

[Darwin]

It’s telling that all branches of the US military have finally begun buying a new 77 grain round called Mk262 (because it was first adapted by the USN for SEALs), in response to many complaints of low stopping power and poor ballistic performance in general of M855 fired from the M4. It won’t replace M855, but the orders keep going up.

Yeah, since the 5.56 round by design uses its high velocity as a component in how it causes damage, the short barrel and lower velocities of the M4 carbine really hurt it, especially in urban combat where the M4's size makes it handy. This is part of the reason for the push towards rounds like the 6.5x39 Grendel and 6.8x43 SPC. Of course changing standard rifle calibers is a huge project, as any look into the initial adoption of the M-16 and 5.56 can show.