With this, my first 'proper' post, I intend to document why the so-called "One Shot Stop" idea is nonsense as well as to explore why so many shooters are sold on the idea and simply argue about which calibre does in fact do it best.
Let's start with that last part, just why do so many gun owners or potential gun owners buy into this idea and then spend time trying to find the "Holy Grail" of calibres and bullet types?
Well, in truth this is not hard to understand at all. Everyone wants to make the best decision they can when purchasing anything, so naturally a potential gun owner wants to buy the best gun in the best calibre and shoot the best brand and type of bullets. Unfortunately, if you were mentally putting quotation marks around "best" in every use of it above, you were quite right. There is no "best handgun" only "the best for John Doe, for use in this particular role and at this particular price". If you think price has nothing to do with it, by the way, consider whether you would be prepared to pay $5,000 for a handgun because there are some out there (and I am not talking relics or stolen military prototypes here, either!) at that price which are largely similar to other guns at less than a tenth of that. Clearly the same ideas apply to choice of calibre and bullet brand / construction too. Now consider that for many people, the major reason for purchasing a handgun is self-defence (typically envisioned as being defence from armed and/or multiple human attackers) and for most of the rest it is the closely related 'dispatch wild animal quickly' task. These are situations where the owner's life would be on the line (we'll ignore that it's very unlikely they would ever have to defend themself, in practice - that's just statistics and I'll cover it another time) and only an idiot would fail to do some research about the 'best' purchase for such a task. Now there are idiots and there are idiots who own or purchase guns but the vast majority of owners or would-be owners are responsible and essentially rational human beings and so they do their research on the laws and the suitability of different types of guns and so on.
"Okay", you say "I undertsand why people want to believe there is such a thing as a best handgun, calibre and cartridge combination but where does this 'One Shot Stop' stuff come in and what is it?"
Good question. It largely came in with Ed Sanow and Evan Marshall who published an article where they claimed to have gathered data on fatal shootings where the assailant was hit by a single shot to their 'centre of mass' (in essence, the [upper] torso) and either stopped or not. They very narrowly defined their criteria as requiring only a single shot, that hit the 'c.o.m' and the attacker stopping whatever it was that prompted the shooting within, I believe, two seconds. Specifically, attacks that were stopped within a very short time but where multiple hits were scored on that area were excluded, also attacks that stopped simply by the assailant surrendering quickly enough, essentially unharmed, where a shot had struck him in the required area were counted. Furthermore, attacks that stopped after the assailant was hit anywhere else, with a single shot, were excluded. Now, it should be obvious to many why this makes no sense at all, literally 'nonsense' but a couple of colourful (verbal) illustrations may assist.
Case 1: Bad Sarge is ex-army and life has not treated him well, he decides he is going into the armed robbery business with a service rifle he has converted to fully automatic. In the course of his attempted getaway from his latest crime scene, he is confronted by armed police and ordered to surrender; laughing, he sprays the area with bullets and once his magazine has emptied the police return fire with their department issue .45 ACP handguns, scoring seven solid hits to BS's torso but failing to drop him. BS escapes in a stolen pickup and decides it's time to get some painkillers as his wounds begin to pain him. BS makes his way in the stolen car to an out-of-the-way 24 hour pharmacy and tries to hold it up for the painkillers, the clerk rather unwisely refuses and pulls a .22 LR target pistol, then shoots Bad Sarge square in his already sore chest. The round barely penetrates BS's denim jacket but he's starting to feel decidedly unwell from the blood loss of his earlier wounds so he surrenders and sits down to await the cops and hopefully an ambulance.
Okay, it's a bit silly but by no means impossible, what would Marshall and Sanow make of it? Well, the first encounter with the cops would be ignored - multiple shots hit his torso, so it doesn't get counted into their 'data'. The second incident however, does count because the clerk fired only one round and hit the assailant in the correct area. In fact, they count it as a 'OSS' because the attack ceased immediately afterwards. I am not kidding, by their stated criteria this would be a "One Shot Stop" with a .22 LR (which is not impossible but seems unlikely given basic knowledge of the calibre's ballistic performance) and tellingly the .22 LR did rather well in their 'survey' (.22 LR is a very common, very inexpensive round so can easily be what happened to be on hand when an attack occurs) and the .45 ACP would be considered to have no data point to gather.
Case 2: Johnny Unhappy is severely depressed; school is not going well, his girlfriend just told him she is lesbian and he spent his last buck on takeout that wasn't even very good. Toying with the idea of pawning the .38 Special revolver he found under the bed when he moved into his apartment, he tucks it into his waistband and heads out. However, the pawn shops have all closed for the night and he's now utterly without interest in life, Johnny decides it's time for "suicide by cop" so he pulls his revolver and starts brandishing it in the middle of the street. Pretty quickly the police are made aware and units speed to the scene, they plead with Johnny to put the firearm down but he points it directly at an officer and pulls the trigger. Panicked, the officers fire on him with their issued 9 mm Parabellum pistols, most go wide but two hit Johnny in the right arm and one severs the brachial artery, causing him to slump and drop the revolver. However, before anything can take place, the sherriff has arrived on the scene just in time to see and hear Johnny discharge the gun, without waiting for further developments that could lead to a dead police officer, Sheriff Kilumall puts a single round from his customized 10 mm Auto semi-automatic, all but destroying Johnny's heart and passing clean through into the car he has slumped against, Johnny is now most certainly dead.
So, back to Marshall and Sanow then. Neither caliber would get a data point from this because multiple shots were fired, however, had the sheriff arrived only slightly early and fired before any other officers, 10 mm Auto would have gained a "OSS" data point for sure. Had the sheriff not fired at all, Johnny would still have been stopped, indeed he had already been stopped, really (and would die without immediate medical attention, indeed emergency surgery). So what does their data actually tell us? Well, basically nothing worthwhile although the frequency of data points for a given calibre is a nice snapshot of the rounds in common use for that time period (9 mm Parabellum came up a lot, IIRC and .357 S&W Magnum too).
"Fair enough, I believe you when you tell me that Marshall and Sanow did a very bad job when setting out to look at this," you say "however, that doesn't mean there could not be a mechanism which makes one of those calibres a 'One Shot Stop' calibre." And you're right, of course, so let's look at why even the idea of 'OSS' as a likely outcome from shooting a particular calibre or bullet type is nonsense too.
Why do people stop doing whatever they are doing that you don't like, when you shoot them? At first this might seem really obvious but actually, it's not. First of all, we must debunk some 'Hollywoodisms' (I will probably do a separate blog on all of those related to firearms but for now this is enough) - [handgun] bullets don't have very much force behind them, they are not actually that energetic and they do not make things explode. Many, if not most, people who are shot in a violent encounter don't even really notice at the moment it happens. As a little food for thought, if you take out a full standard-sized bag of sugar and drop it from your kitchen counter, that is at least as much energy as a .45 ACP bullet has when it leaves the muzzle of a handgun. Martial artists, boxers and sportsmen regularly deal with many times greater impacts, boxers and martial artists punch much, much harder. Clearly the 'stopping power' of a handgun bullet has nothing to do with some sort of mystical energy transfer then (another myth I will more thoroughly tackle later), so what else does the bullet do? It penetrates through its target disrupting its structure and if it has sufficient momentum and the right shape, it passes through to the other side having wrought considerable damage to that object, in all likelihood. When this happens to people, then, they drop dead, right? Well, no, not really. Consider just how badly beaten up someone can be and still survive, even without medical attention. Of course, having a few holes in you is bad for anyone's health but even five minutes would be a relatively long time for a determined attacker to do whatever it is that made you choose to shoot them; if they die five minutes after they have killed you that will be no use to you and cold comfort to your surviving family and friends.
"Hang on a minute!" You say, "That sounds an awful lot like you want a 'one shot stop' yourself, what gives?" Well, no. I want a STOP and I am prepared to keep shooting until I get one, reloading if necessary. I advocate others doing likewise. I will shoot repeatedly at the attacker's 'centre of mass' AKA torso until he stops charging me, shooting at me or whatever else it is that gave me reasonable cause to open fire on him, then I will call the emergency services and wait for them to arrive and keep my mouth mostly shut until I have calmed down and given my full story to a lawyer. Why I would do this is the next part, though.
What will stop a human being quickly, absolutely without fail, then? Destruction of the heart, although a person can be active for as much as thirty seconds afterwards (really), in spite of the loss of blood pressure. Destruction of part the central nervous system, which means in practical terms significant damage to the brain or spine (this is 'Game Over' - I know of no instances of anyone managing to do anything at all immediately afterwards, where this was recorded as happening). Significant damage to major blood vessels, such as carotid artery, brachial artery, pulmonary artery will at the least lead to loss of consciousness unless medical attention is received very quickly but once again determined assailants have been known to carry on for surprising lengths of time, even several minutes; such injuries would rapidly 'stack up' though so inflicting them is worthwhile. You will notice that shooting for the torso (centre of mass, if you prefer that term) makes all of these possible with the proper aim and some luck and everyone knows you make your own luck with practice and stacking the deck in your favour.
"Okay, great, so I shoot for the chest and keep shooting till I hit something important enough to incapacitate and possibly kill my attacker? Great!"
Well, yes and no. There is no point shooting with a firearm and calibre combination that simply cannot do that and for some easily encountered scenarios it can be shown that some combinations cannot do that and others cannot reliably do it. This is the kernel of truth at the heart of the mess that is 'OSS'. Trying to find a combination of factors that make it likely for you to survive an encounter where you are forced to shoot 'the other guy' is perfectly valid and is the basis of the hunt for that Magic Bullet and Magic Gun that will "One Shot Stop" a bad guy™.
The primary thing you need from cartridge/gun combo is penetration. That is because even with a slightly built person (I myself am very slim, albeit quite tall) you will have to go through at least 8 inches of flesh and bone if you're forced to shoot me from the side, having already penetrated any clothing I am wearing. Clothing is by no means irrelevant either; a denim jacket will stop a surprising number of small calibre bullets and render others ineffective due to too shallow a wound. Clearly I am not suggesting you rely on a denim jacket as a 'bullet-proof vest' but I am saying that shooting someone with .22 LR in a clothed area is almost certain to do nothing but piss them off (even if it penetrates the clothing). Conversely, should someone be unfortunate enough to be shot with a .44 Remington Magnum cartridge fired from a long-barrelled revolver, their odds are very poor unless it was a peripheral wound or a glancing shot ('flesh wound') because these bullets are relatively massive ('heavy') and have very good momentum (they're quite fast when fired from a sufficiently long barrel and speed combined with mass is momentum, which is what really matters - more in another blog) leading to excellent penetration and a lot of damage on the way through (and it very likely will go through) thanks to also being relatively large diameter. In short, a very bad day for the victim.
I'm not going to rehash much more detailed examinations of terminal ballistics by people like Martin Fackler and others, so here is the short and dirty. The wider the hole, the more tissue damage was done and the greater the blood loss will be, also there is a better chance of damaging a nearby blood vessel or doing more damage to the one you hit. A longer hole is better because 'see above', also you need to be able to go in quite far to have a hope of hitting the really important stuff and/or passing through bone to go on and hit anything behind it. That's it in very simple terms. Bullet construction is a much more complex topic and different factors apply in different applications (such as a rifle bullet compared to a handgun bullet) however I will tackle 'hollowpoints', 'ball' ammunition and 'semi-wadcutters'. With other factors being equal, 'ball' ammunition will penetrate further typically - it literally pushes tissue aside (doing less damage) and keeps going until the pressure of tissue ahead of it is great enough to bring the bullet to a stop, make it flip or make it break up (or else it exits because the pressure never reached that threshold, such as with a bullet that still has a lot of momentum when it approaches the skin from the inside of a body). Hollowpoints have a sort of semi-mythical status in some quarters but they definitely have valid application - hollowpoints and more generally 'expanding ammunition' make wider holes at the cost of penetration; some of their momentum ends up being used to do work (technical term, look it up) on the bullet, deforming it in a predictable, designed way so as to make it larger, also as its area has been increased it faces more resistance and slows more rapidly in the tissue. 'Semi-wadcutters' and similar bullet designs with flattened meplats (a technical term that you can think of as "front face of bullet") efficiently crush tissue causing more damage than 'ball' ammuntion but slowing less quickly than expanding bullet designs, so achieving better penetration.
Okay, so what happens if you have shoot through stuff other than flesh to get to the bad guys fleshy bits? Well, ball does the best of all, basically, since it will tend to deform the least, semi-wadcutters with a good charge behind them score pretty decently too but are going to be slowed quite a lot more than ball would be and hollowpoints or other expanding ammunition designs can be unpredictable - they might expand and 'waste' their momentum on the barrier or they pass through because it doesn't quite have the right properties to make the bullet expand (basically behaving quite similarly to semi-wadcutters or even ball, depending on their shape) but often if that happens they have been 'plugged' by barrier material or slowed sufficiently by it that they will not expand in the target, either.
So, which do you use? Well, it's hotly debated and it really should vary according to the precise loading, calibre and barrel length but some people swear by expanding bullets others swear at them and flat meplats are mostly used in calibres where they are the accepted default bullet design (e.g. most 10 mm Auto loadings seem to be). Myself, I tend to think that the risk of insufficient penetration when you need it most outweighs the advantages of possible expansion (and thus a possibly more effective wound) so as it stands I am disinclined to rely on them but I stop short of saying they are "bad" because they're not they just don't fit with the way I want my bullets to perform. Others will tell you that the danger of overpenetration is a good reason to use them, after all in the 'worst case' scenario, they assure me, it behaves a lot like any other useful bullet design but in a 'best case' there is adequate penetration and good expansion; wide and long, just like we want. Interestingly, tests suggest that expanding ammunition quite often isn't and quite often overpenetrates more than comparable ball but that's in cases where it passed through a barrier. Make up your own mind for your own reasons and be at ease with them but don't get dogmatic on it. For the curious, my preferred calibre is 10 mm Auto, in at least 180 grains with a flat meplat bullet design. I like this because the bullet is pretty massive, reasonably wide, has a very flat trajectory for handgun rounds and has a lot of moment even quite far downrange, with which to crush tissue and still penetrate well. Ideally, I like 200 grain bullets at similar or slightly reduced speed and the same bullet design - even more momentum conserved through the path.
"Okay, fair enough, what about the police and lawyer and keeping quiet?"
If you are forced to exercize your right to lawful self-defence you will still have to explain your actions. You will need to show, in essence, that three things were present - that the attacker had the ability to do you serious or life-ending harm, that the attacker had the opportunity to do that same degree of harm and that you had grounds to believe he was about to or in the process of doing so when you shot him, with such grounds being enough for a 'reasonable person' who knew no more and no less than what you knew at the time to have reached the same conclusion. In layman's terms, he needed to have the ability to kill or maim you, the opportunity to do so and be doing so or about to do so, in the opinion of yourself with enough evidence of that for anyone else who saw what you saw, heard what you heard and knew what you knew to have the same opinion.
So, why call the emergency services? To get an ambulance; your attacker may well be dead but you're not qualified to make that assumption so you are expected to treat them as if they were some seriously wounded person that you have come across; even murderous idiot criminals get to be treated for their injuries, if they live, it's the state's job to execute them later. Furthermore, the police will have questions, will want to document the scene and take statements from witnesses and will want to take your firearm as evidence (as well as possible suspending licences for firearms until after their investigation and possibly until after a court hearing or even a court case). They may very well arrest you and charge you until they have ascertained the full facts - remember, at that moment all they have is a dead or dying person on the ground and someone else who was armed and has apparently shot that person.
Why keep your mouth mostly shut? Put simply, you can never jeopardize your defence with something you didn't say. If you were justified in shooting, you will have no problem giving an accurate (as far as you can recall) and full account of the incident, in broad daylight, in a calm setting, having been able to think it all through and settle your nerves. Your lawyer will by then have been able to codify that acount of events into a checklist of things that back up your story and show that you satisfied the requirements for a defence of 'armed self-defence'. The police will be keen to press for details as they know that the sooner they can get a statement the more likely it is to contain details that will make their job easier, from the point of view of a prosecution and you are essentially a suspect in a slaying when they arrive on the scene, even if they are sympathetic.
Let's start with that last part, just why do so many gun owners or potential gun owners buy into this idea and then spend time trying to find the "Holy Grail" of calibres and bullet types?
Well, in truth this is not hard to understand at all. Everyone wants to make the best decision they can when purchasing anything, so naturally a potential gun owner wants to buy the best gun in the best calibre and shoot the best brand and type of bullets. Unfortunately, if you were mentally putting quotation marks around "best" in every use of it above, you were quite right. There is no "best handgun" only "the best for John Doe, for use in this particular role and at this particular price". If you think price has nothing to do with it, by the way, consider whether you would be prepared to pay $5,000 for a handgun because there are some out there (and I am not talking relics or stolen military prototypes here, either!) at that price which are largely similar to other guns at less than a tenth of that. Clearly the same ideas apply to choice of calibre and bullet brand / construction too. Now consider that for many people, the major reason for purchasing a handgun is self-defence (typically envisioned as being defence from armed and/or multiple human attackers) and for most of the rest it is the closely related 'dispatch wild animal quickly' task. These are situations where the owner's life would be on the line (we'll ignore that it's very unlikely they would ever have to defend themself, in practice - that's just statistics and I'll cover it another time) and only an idiot would fail to do some research about the 'best' purchase for such a task. Now there are idiots and there are idiots who own or purchase guns but the vast majority of owners or would-be owners are responsible and essentially rational human beings and so they do their research on the laws and the suitability of different types of guns and so on.
"Okay", you say "I undertsand why people want to believe there is such a thing as a best handgun, calibre and cartridge combination but where does this 'One Shot Stop' stuff come in and what is it?"
Good question. It largely came in with Ed Sanow and Evan Marshall who published an article where they claimed to have gathered data on fatal shootings where the assailant was hit by a single shot to their 'centre of mass' (in essence, the [upper] torso) and either stopped or not. They very narrowly defined their criteria as requiring only a single shot, that hit the 'c.o.m' and the attacker stopping whatever it was that prompted the shooting within, I believe, two seconds. Specifically, attacks that were stopped within a very short time but where multiple hits were scored on that area were excluded, also attacks that stopped simply by the assailant surrendering quickly enough, essentially unharmed, where a shot had struck him in the required area were counted. Furthermore, attacks that stopped after the assailant was hit anywhere else, with a single shot, were excluded. Now, it should be obvious to many why this makes no sense at all, literally 'nonsense' but a couple of colourful (verbal) illustrations may assist.
Case 1: Bad Sarge is ex-army and life has not treated him well, he decides he is going into the armed robbery business with a service rifle he has converted to fully automatic. In the course of his attempted getaway from his latest crime scene, he is confronted by armed police and ordered to surrender; laughing, he sprays the area with bullets and once his magazine has emptied the police return fire with their department issue .45 ACP handguns, scoring seven solid hits to BS's torso but failing to drop him. BS escapes in a stolen pickup and decides it's time to get some painkillers as his wounds begin to pain him. BS makes his way in the stolen car to an out-of-the-way 24 hour pharmacy and tries to hold it up for the painkillers, the clerk rather unwisely refuses and pulls a .22 LR target pistol, then shoots Bad Sarge square in his already sore chest. The round barely penetrates BS's denim jacket but he's starting to feel decidedly unwell from the blood loss of his earlier wounds so he surrenders and sits down to await the cops and hopefully an ambulance.
Okay, it's a bit silly but by no means impossible, what would Marshall and Sanow make of it? Well, the first encounter with the cops would be ignored - multiple shots hit his torso, so it doesn't get counted into their 'data'. The second incident however, does count because the clerk fired only one round and hit the assailant in the correct area. In fact, they count it as a 'OSS' because the attack ceased immediately afterwards. I am not kidding, by their stated criteria this would be a "One Shot Stop" with a .22 LR (which is not impossible but seems unlikely given basic knowledge of the calibre's ballistic performance) and tellingly the .22 LR did rather well in their 'survey' (.22 LR is a very common, very inexpensive round so can easily be what happened to be on hand when an attack occurs) and the .45 ACP would be considered to have no data point to gather.
Case 2: Johnny Unhappy is severely depressed; school is not going well, his girlfriend just told him she is lesbian and he spent his last buck on takeout that wasn't even very good. Toying with the idea of pawning the .38 Special revolver he found under the bed when he moved into his apartment, he tucks it into his waistband and heads out. However, the pawn shops have all closed for the night and he's now utterly without interest in life, Johnny decides it's time for "suicide by cop" so he pulls his revolver and starts brandishing it in the middle of the street. Pretty quickly the police are made aware and units speed to the scene, they plead with Johnny to put the firearm down but he points it directly at an officer and pulls the trigger. Panicked, the officers fire on him with their issued 9 mm Parabellum pistols, most go wide but two hit Johnny in the right arm and one severs the brachial artery, causing him to slump and drop the revolver. However, before anything can take place, the sherriff has arrived on the scene just in time to see and hear Johnny discharge the gun, without waiting for further developments that could lead to a dead police officer, Sheriff Kilumall puts a single round from his customized 10 mm Auto semi-automatic, all but destroying Johnny's heart and passing clean through into the car he has slumped against, Johnny is now most certainly dead.
So, back to Marshall and Sanow then. Neither caliber would get a data point from this because multiple shots were fired, however, had the sheriff arrived only slightly early and fired before any other officers, 10 mm Auto would have gained a "OSS" data point for sure. Had the sheriff not fired at all, Johnny would still have been stopped, indeed he had already been stopped, really (and would die without immediate medical attention, indeed emergency surgery). So what does their data actually tell us? Well, basically nothing worthwhile although the frequency of data points for a given calibre is a nice snapshot of the rounds in common use for that time period (9 mm Parabellum came up a lot, IIRC and .357 S&W Magnum too).
"Fair enough, I believe you when you tell me that Marshall and Sanow did a very bad job when setting out to look at this," you say "however, that doesn't mean there could not be a mechanism which makes one of those calibres a 'One Shot Stop' calibre." And you're right, of course, so let's look at why even the idea of 'OSS' as a likely outcome from shooting a particular calibre or bullet type is nonsense too.
Why do people stop doing whatever they are doing that you don't like, when you shoot them? At first this might seem really obvious but actually, it's not. First of all, we must debunk some 'Hollywoodisms' (I will probably do a separate blog on all of those related to firearms but for now this is enough) - [handgun] bullets don't have very much force behind them, they are not actually that energetic and they do not make things explode. Many, if not most, people who are shot in a violent encounter don't even really notice at the moment it happens. As a little food for thought, if you take out a full standard-sized bag of sugar and drop it from your kitchen counter, that is at least as much energy as a .45 ACP bullet has when it leaves the muzzle of a handgun. Martial artists, boxers and sportsmen regularly deal with many times greater impacts, boxers and martial artists punch much, much harder. Clearly the 'stopping power' of a handgun bullet has nothing to do with some sort of mystical energy transfer then (another myth I will more thoroughly tackle later), so what else does the bullet do? It penetrates through its target disrupting its structure and if it has sufficient momentum and the right shape, it passes through to the other side having wrought considerable damage to that object, in all likelihood. When this happens to people, then, they drop dead, right? Well, no, not really. Consider just how badly beaten up someone can be and still survive, even without medical attention. Of course, having a few holes in you is bad for anyone's health but even five minutes would be a relatively long time for a determined attacker to do whatever it is that made you choose to shoot them; if they die five minutes after they have killed you that will be no use to you and cold comfort to your surviving family and friends.
"Hang on a minute!" You say, "That sounds an awful lot like you want a 'one shot stop' yourself, what gives?" Well, no. I want a STOP and I am prepared to keep shooting until I get one, reloading if necessary. I advocate others doing likewise. I will shoot repeatedly at the attacker's 'centre of mass' AKA torso until he stops charging me, shooting at me or whatever else it is that gave me reasonable cause to open fire on him, then I will call the emergency services and wait for them to arrive and keep my mouth mostly shut until I have calmed down and given my full story to a lawyer. Why I would do this is the next part, though.
What will stop a human being quickly, absolutely without fail, then? Destruction of the heart, although a person can be active for as much as thirty seconds afterwards (really), in spite of the loss of blood pressure. Destruction of part the central nervous system, which means in practical terms significant damage to the brain or spine (this is 'Game Over' - I know of no instances of anyone managing to do anything at all immediately afterwards, where this was recorded as happening). Significant damage to major blood vessels, such as carotid artery, brachial artery, pulmonary artery will at the least lead to loss of consciousness unless medical attention is received very quickly but once again determined assailants have been known to carry on for surprising lengths of time, even several minutes; such injuries would rapidly 'stack up' though so inflicting them is worthwhile. You will notice that shooting for the torso (centre of mass, if you prefer that term) makes all of these possible with the proper aim and some luck and everyone knows you make your own luck with practice and stacking the deck in your favour.
"Okay, great, so I shoot for the chest and keep shooting till I hit something important enough to incapacitate and possibly kill my attacker? Great!"
Well, yes and no. There is no point shooting with a firearm and calibre combination that simply cannot do that and for some easily encountered scenarios it can be shown that some combinations cannot do that and others cannot reliably do it. This is the kernel of truth at the heart of the mess that is 'OSS'. Trying to find a combination of factors that make it likely for you to survive an encounter where you are forced to shoot 'the other guy' is perfectly valid and is the basis of the hunt for that Magic Bullet and Magic Gun that will "One Shot Stop" a bad guy™.
The primary thing you need from cartridge/gun combo is penetration. That is because even with a slightly built person (I myself am very slim, albeit quite tall) you will have to go through at least 8 inches of flesh and bone if you're forced to shoot me from the side, having already penetrated any clothing I am wearing. Clothing is by no means irrelevant either; a denim jacket will stop a surprising number of small calibre bullets and render others ineffective due to too shallow a wound. Clearly I am not suggesting you rely on a denim jacket as a 'bullet-proof vest' but I am saying that shooting someone with .22 LR in a clothed area is almost certain to do nothing but piss them off (even if it penetrates the clothing). Conversely, should someone be unfortunate enough to be shot with a .44 Remington Magnum cartridge fired from a long-barrelled revolver, their odds are very poor unless it was a peripheral wound or a glancing shot ('flesh wound') because these bullets are relatively massive ('heavy') and have very good momentum (they're quite fast when fired from a sufficiently long barrel and speed combined with mass is momentum, which is what really matters - more in another blog) leading to excellent penetration and a lot of damage on the way through (and it very likely will go through) thanks to also being relatively large diameter. In short, a very bad day for the victim.
I'm not going to rehash much more detailed examinations of terminal ballistics by people like Martin Fackler and others, so here is the short and dirty. The wider the hole, the more tissue damage was done and the greater the blood loss will be, also there is a better chance of damaging a nearby blood vessel or doing more damage to the one you hit. A longer hole is better because 'see above', also you need to be able to go in quite far to have a hope of hitting the really important stuff and/or passing through bone to go on and hit anything behind it. That's it in very simple terms. Bullet construction is a much more complex topic and different factors apply in different applications (such as a rifle bullet compared to a handgun bullet) however I will tackle 'hollowpoints', 'ball' ammunition and 'semi-wadcutters'. With other factors being equal, 'ball' ammunition will penetrate further typically - it literally pushes tissue aside (doing less damage) and keeps going until the pressure of tissue ahead of it is great enough to bring the bullet to a stop, make it flip or make it break up (or else it exits because the pressure never reached that threshold, such as with a bullet that still has a lot of momentum when it approaches the skin from the inside of a body). Hollowpoints have a sort of semi-mythical status in some quarters but they definitely have valid application - hollowpoints and more generally 'expanding ammunition' make wider holes at the cost of penetration; some of their momentum ends up being used to do work (technical term, look it up) on the bullet, deforming it in a predictable, designed way so as to make it larger, also as its area has been increased it faces more resistance and slows more rapidly in the tissue. 'Semi-wadcutters' and similar bullet designs with flattened meplats (a technical term that you can think of as "front face of bullet") efficiently crush tissue causing more damage than 'ball' ammuntion but slowing less quickly than expanding bullet designs, so achieving better penetration.
Okay, so what happens if you have shoot through stuff other than flesh to get to the bad guys fleshy bits? Well, ball does the best of all, basically, since it will tend to deform the least, semi-wadcutters with a good charge behind them score pretty decently too but are going to be slowed quite a lot more than ball would be and hollowpoints or other expanding ammunition designs can be unpredictable - they might expand and 'waste' their momentum on the barrier or they pass through because it doesn't quite have the right properties to make the bullet expand (basically behaving quite similarly to semi-wadcutters or even ball, depending on their shape) but often if that happens they have been 'plugged' by barrier material or slowed sufficiently by it that they will not expand in the target, either.
So, which do you use? Well, it's hotly debated and it really should vary according to the precise loading, calibre and barrel length but some people swear by expanding bullets others swear at them and flat meplats are mostly used in calibres where they are the accepted default bullet design (e.g. most 10 mm Auto loadings seem to be). Myself, I tend to think that the risk of insufficient penetration when you need it most outweighs the advantages of possible expansion (and thus a possibly more effective wound) so as it stands I am disinclined to rely on them but I stop short of saying they are "bad" because they're not they just don't fit with the way I want my bullets to perform. Others will tell you that the danger of overpenetration is a good reason to use them, after all in the 'worst case' scenario, they assure me, it behaves a lot like any other useful bullet design but in a 'best case' there is adequate penetration and good expansion; wide and long, just like we want. Interestingly, tests suggest that expanding ammunition quite often isn't and quite often overpenetrates more than comparable ball but that's in cases where it passed through a barrier. Make up your own mind for your own reasons and be at ease with them but don't get dogmatic on it. For the curious, my preferred calibre is 10 mm Auto, in at least 180 grains with a flat meplat bullet design. I like this because the bullet is pretty massive, reasonably wide, has a very flat trajectory for handgun rounds and has a lot of moment even quite far downrange, with which to crush tissue and still penetrate well. Ideally, I like 200 grain bullets at similar or slightly reduced speed and the same bullet design - even more momentum conserved through the path.
"Okay, fair enough, what about the police and lawyer and keeping quiet?"
If you are forced to exercize your right to lawful self-defence you will still have to explain your actions. You will need to show, in essence, that three things were present - that the attacker had the ability to do you serious or life-ending harm, that the attacker had the opportunity to do that same degree of harm and that you had grounds to believe he was about to or in the process of doing so when you shot him, with such grounds being enough for a 'reasonable person' who knew no more and no less than what you knew at the time to have reached the same conclusion. In layman's terms, he needed to have the ability to kill or maim you, the opportunity to do so and be doing so or about to do so, in the opinion of yourself with enough evidence of that for anyone else who saw what you saw, heard what you heard and knew what you knew to have the same opinion.
So, why call the emergency services? To get an ambulance; your attacker may well be dead but you're not qualified to make that assumption so you are expected to treat them as if they were some seriously wounded person that you have come across; even murderous idiot criminals get to be treated for their injuries, if they live, it's the state's job to execute them later. Furthermore, the police will have questions, will want to document the scene and take statements from witnesses and will want to take your firearm as evidence (as well as possible suspending licences for firearms until after their investigation and possibly until after a court hearing or even a court case). They may very well arrest you and charge you until they have ascertained the full facts - remember, at that moment all they have is a dead or dying person on the ground and someone else who was armed and has apparently shot that person.
Why keep your mouth mostly shut? Put simply, you can never jeopardize your defence with something you didn't say. If you were justified in shooting, you will have no problem giving an accurate (as far as you can recall) and full account of the incident, in broad daylight, in a calm setting, having been able to think it all through and settle your nerves. Your lawyer will by then have been able to codify that acount of events into a checklist of things that back up your story and show that you satisfied the requirements for a defence of 'armed self-defence'. The police will be keen to press for details as they know that the sooner they can get a statement the more likely it is to contain details that will make their job easier, from the point of view of a prosecution and you are essentially a suspect in a slaying when they arrive on the scene, even if they are sympathetic.
