Is a single stack enough?

Here are links link to John's posts from five years ago.

It is worth a very careful and thoughtful read. Before you start, recognize that hitting an attacker will not effect a true physical stop unless something critical inside the body is struck.

You can vary the assumptions regarding hit rate and the number of hits required to suit yourself, and run your own numbers.

I happen to think that, based in John's assumptions, these are "best case" calculations, for one simple reason: they assume that the defender will stop shooting immediately after firing the shot that stops. I do not think that realistic.

The gist:

I was surprised at how tough it was to neutralize 2 assailants given a 30% hit rate and 5 shots. Basically one can expect to succeed 3 times in 100 attempts.

To improve those odds to EVEN odds (roughly a 50/50 chance of success) when using a 5 shot handgun, one would need to shoot well enough to achieve a 69% hit rate during a gunfight. A 69% hit rate would give a person with a 5 shot handgun a 50.1% chance of succeeding against two opponents who each require 2 hits to be neutralized.

From a practical standpoint, the probabilities involved suggest that someone armed with a typical small carry pistol (11 rounds or less) and achieving a hit rate of about 30% per shot has better than even odds of failing to neutralize 2 opponents before their gun is emptied. Under the same conditions, someone armed with a true pocket pistol (7 rounds or less) is likely to fail to neutralize 2 assailants about 90% of the time or more.

Even with only a single assailant, a pocket pistol will run dry somewhere between 1/3 and 1/2 of the time before a 30% hit rate achieves 2 hits.​

That is why I said that I prefer a ten or twelve shot capacity.

As it happens, I carry eight for a number of reasons, and I am not altogether happy with that.




Again, if you do not like the assumptions run the numbers with your own, and while you're at it, consider how any shots you will likely fire, based on your training, at that first attacker before you can readably stop shooting to assess the results.
 
@Brit, Is that the average conversation you have with someone you meet that carries?

Well yes, when I arrived in Orlando, in 2003. Left my training Company with my partner, that did not go well.

The idea was I would check out the feasibility to start a Company like I had in Toronto. As I am a chatty kind of Guy, I did a lot of that. Talking about where people were with their thoughts on pistols, carrying them, shooting them, etc.

But you can not instantly start, no Green card, no License to carry, no training guns, no range.

So is a single stack enough? No, and why? Because more is better, always.

G19 with 16 rounds, ready to go, no reload required. G17 magazine, 17 rounds of NATO Hard Ball. In case I had to poke holes in a car, or thin wall.

How do I justify all those rounds? I don't have too.
 
Thanks for the link to that other thread, OM. It was a good read. I saw that a lot of the posters in it did not understand what was being presented to them, but perhaps they are not familiar with using probabilities other than at an intuitive level, which can sometimes be completely wrong. Hence the value of the math.
 
JohnKSa said:
The problem, of course is that people tend to miss a lot when they're getting shot at. Police hit rates tend to average under 50%.

Some years ago, when I first ran the numbers for typical subcompact capacity and reasonable hit rate percentages, I was dismayed at how unlikely it was that one could prevail against two determined attackers with 5-7 rounds...
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Last year a local deputy fired 28 shots at a suspect that pointed his gun at him and may have fired a shot or two. He hit the suspect once in the hand.

http://www.wenatcheeworld.com/news/2016/aug/05/jury-acquits-man-who-provoked-deputys-gunfire/
 
I've only had my CC for a couple years, but carry every day. I started with my LC9s because it's what I had and it's been 100% reliable and I shoot it accurately. Then I felt I needed more capacity, so next was a Taurus Millenium G2, easy to carry, felt great in my hand, good reviews,and the price was irresistible. But, I don't shoot it as accurately and it hasn't been as reliable as the reviews would lead you to believe. Next I tried a FNS 9C, which at first I liked a lot, but not very comfortable to carry, and for me once again a little picky on ammo and I don't shoot it as accurately as I'd like. So now I'm just back to the LC9s with two extra 10 round mags and good to go. Now, as far as my accuracy issues, both the Taurus and FN are more than combat accurate but I require more than that. As far as them being finicky on ammo, once I got it nailed on reliable ammo they were fine, but the Ruger would just eat anything I fed it and shoot more accurately.
 
While I used to carry 12-to-15rd double stacks in the past, I now EDC a Shield 9mm w/a MagGuts +2 conversion on the primary mag (so 10+1 plus 2x8rd reloads in a Recluse leather hip pocket mag carrier).

Why? I shoot it well, it's easy/comfortable to conceal/carry (which means I'll carry it more often) and the Shield's tapered mags make reloads faster/easier.

If I frequented bad parts of town, lived in a high-crime city or worked in a high-risk environment I would carry something w/more capacity (and will do so again in the future should circumstances warrant it). But until then I feel the Shield + reloads is adequate for my needs (YMMV).

Tomac
 
Sorry, OM, I respectfully disagree.
IMHO it comes down to perceived risk and the personal evaluation as to the proper response to that perceived risk.
One cannot predict the level of threat when/if it appears but one can estimate the difference in potential risk between, say, sitting at home w/locked doors and walking through urban Detroit w/$100 bills hanging out of your pockets.

While all handguns are relatively poor 'stoppers' regardless of caliber or bullet used (shot placement and sufficient penetration are paramount, all else is secondary), as previously mentioned one plays the odds against ever having to draw a concealed handgun, much less shooting one or more attackers (I've been carrying for over 40yrs and have yet to encounter a situation where I *might* have to draw my handgun, much less fire it).

Unless you actually have to shoot enough in a self-defense situation to run your gun dry (and what are the perceived odds of that?), capacity doesn't matter (and IIRC, John Lott's research indicates the mere presence of a firearm ends many attacks w/o having to fire).

Like how much car insurance, do you choose full coverage (including tows, replacement rental, etc) for 'just in case' or liability-only w/your fingers crossed hoping you never have to use it?

What it comes down to is being good w/what you're comfortable carrying whether it's a 5-shot .38 or 17-shot full-size 9mm while hoping A) You never have to use it, and B) It's sufficient to stop the threat if you do have to use it.

JMHO...

Tomac
 
One cannot predict the level of threat when/if it appears but one can estimate the difference in potential risk between, say, sitting at home w/locked doors and walking through urban Detroit w/$100 bills hanging out of your pockets.
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One can certainly try to assess the differences in likelihood that a risk will materialize in different kinds of situations.

But I think it would be very naive to assume that one can characterize differences in what would be required to handle the risk, once the risk materializes.

Forget a gang attack, or a situation involving riots.

Consider car jackings, home burglaries, armed robberies, etc. While the risk of occurrence all vary, here is no reason to believe that there would be much difference in the nature of defensive use of force incidents that occur within your home, at an ATM in a bad part of Philadelphia, in a lot outside a big box store in a good suburban area, or at a gas station in town or along the interstate,once theviolent event occurs.

Thus, there is no real difference in how one should generally equip oneself to handle the situation, should it occur..

...as previously mentioned one plays the odds against ever having to draw a concealed handgun, much less shooting one or more attackers (I've been carrying for over 40yrs and have yet to encounter a situation where I *might* have to draw my handgun, much less fire it).
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That takes us back to the evaluation of likelihood, and it does not help us decide how to prepare, if we do decide to mitigate the risk in the first place.

Unless you actually have to shoot enough in a self-defense situation to run your gun dry (and what are the perceived odds of that?), capacity doesn't matter....
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That was the subject of the discussion in the links in Post #122.

...John Lott's research indicates the mere presence of a firearm ends many attacks w/o having to fire).
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Yes indeed.

But the discussion of capacity is only meaningful when one does have to fire.

This is a very basic tenet of risk management.

Try to look at it this way:

Suppose one is considering buying a fire extinguisher for the kichen. Some people do, some do not. I have one.

The fire department may come out and tell us that for our kitchen, we should choose, say a ten pound extinguisher of a certain type.

The extremely low likelihood of occurrence of a kitchen fire should not affect the product selection, once the decision to purchase has been made. On an expected value basis (which would take into account the likelihood of occurrence), each household would need to have about two tenths of an ounce of extinguishing material in the kitchen.

But buying a tiny little vial because the risk of occurrence is very low wouldn't make any sense at all, would it?

No. One starts with the assumption that, however unlikely the occurrence may have been, the balloon has gone up, so to speak.

The misconception is understandable. For one to feel stupid, though, one would have to work for several yards in the design and implementation and testing of various kinds of risk management processes, and then go out and buy a five shot pocket revolver to carry in areas where the likelihood of needing a firearm is thought to be low.

I am, of course, describing myself. Some kind person on another board challenged my thinking.

As Tom Givens advises, "carry a real gun."
 
What it comes down to is being good w/what you're comfortable carrying whether it's a 5-shot .38 or 17-shot full-size 9mm while hoping A) You never have to use it, and B) It's sufficient to stop the threat if you do have to use it.
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Well, if it's just about "feeling comfortable" then maybe that's true. But if we decide we actually want to plan for a specific scenario then it's not really just about what a person is comfortable carrying. B) can be a problem with some carry choices if you look at the probabilities even for reasonable scenarios.

Let's start with some assumptions.

1. We want to make sure we carry something that gives us a better than 50/50 chance of "winning" against a single determined attacker.
2. It takes 2-3 hits to stop a determined attacker.
3. A reasonable hit rate probability per shot in a gunfight is 30%.

Pretty basic stuff; we could restate those assumptions by saying that we want our gun to serve as more than a talisman we hold up to make evil magically disappear, and that we acknowledge that people miss when under extreme pressure and that determined humans don't stop at the first sign of resistance.

Is preparing for a single determined attacker reasonable? Well, that's pretty much the minimum scenario where you would actually need to have a loaded gun. If the attacker isn't determined (and admittedly many--maybe even most--aren't), then when you start to draw, the encounter is already over--it's only when the attacker is determined that actually shooting will be necessary.

So let's look at the best case probabilities for that scenario.

A 5 shot pocket gun won't meet the success threshold. If we need to make 2-3 hits, the probability of making those hits before the gun runs dry is 16% (3 hits required) to 47% (2 hits required). A person who wants to prepare for the scenario above (single determined attacker where 50/50 is the minimum acceptable probability of success, 2-3 hits are required to neutralize and a hit rate probability of 30%) shouldn't pick a 5 shot pocket gun. It doesn't matter how comfortable it is to carry or how comfortable they feel about carrying a 5 shot gun. It just doesn't meet the success criterion that they set as being reasonable.

Let's look at a 6 shot gun. The odds of making 2-3 hits is 26% (3 hits required) to 58% (2 hits required). It only meets our established success criteria on the low end (2 hits required to stop) but won't give us an acceptable probability of success if it takes 3 hits to end the encounter.

Cutting to the chase, one needs to have 9 shots on tap before the defender has better than 50/50 odds of making 2-3 hits. The probabilities are 54% (3 hits required) to 80% (2 hits required) of success.

It's important to understand that a 9 shot gun doesn't guarantee success. What it does is provide an acceptable probability of success in the best case scenario--it gives you better than a 50/50 chance of success if all that's required is 2-3 hits and you get a chance to use all your ammo. Obviously there are still many things that could go wrong. Things like getting shot before you get your 2-3 hits, the gun jamming before you get off all your hits, never even getting the chance to draw, 2-3 hits not being enough to stop, etc.

On the other hand, a gun with less than 9 shots, no matter how comfortable it is to carry or how comfortable the defender is with carrying it, just won't give the probability of success we set as being the minimum acceptable. A person who wants to prepare for the scenario above (single determined attacker where better than 50/50 is the minimum acceptable probability of success, 2-3 hits are required to neutralize and a hit rate probability of 30% is assumed) but is carrying a 5, 6, 7 or 8 shot gun is actually preparing for failure, not success.

The point isn't that carrying more rounds will guarantee success, the point is that we need to be realistic about what we're preparing for. Or, said another way, given a particular carry gun, we need to be realistic about what we are actually prepared for.

This helps us keep a proper perspective. I see people talking about going up against multiple determined attackers with a pocket pistol--maybe to end an active shooters scenario. Should you do that? Well, you'll have to make the decision on the fly based on how you see the circumstances of the scenario. What this analysis provides is a reasonable perspective on what your chances of success are.

Once we understand what reality is, it helps us make better risk assessments.

It can also help us understand the value of training and skill.

Let's play a "What if?" game. What if we could increase our effective hit rate per shot from 30% to 35%? Even with that relatively small increase in hit rate, now an 8 shot gun provides a higher probability of success (57% if 3 hits required to 83% if 2 hits are required) than we saw earlier with a 9 shot gun and a 30% hit rate.

So with just that incremental increase in skill, now we could carry a slightly smaller, lighter gun and actually be slightly better prepared. Or, said another way, if we carry the same 9 shot gun, now we have one "spare" round that might bail us out in a particularly sticky situation.
 
Species on the numbers being used for calculation?
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Yes, of course. They were of the species Real. :D

Ok, assuming you mean "Specifics", the answer is:

1. The assumptions for setting up the scenario are carefully defined in the post to avoid confusion. I'm not saying that those assumptions will govern every gunfight. I'm just saying that if you want to do analysis then you have to make some assumptions about what kind of scenario you're going to analyze. I think that the assumptions made are reasonable, but a different set of assumptions could be made based on a defender with a different skill level or based on the idea that a determined attacker might require more (or fewer) hits to be neutralized. And, one could also decide that they want to set a different threshold than "better than 50/50" for the overall probability of success.

2. The calculations were performed using the standard rules of probability. Using those rules you should be able to duplicate them just as JC57 did in post #80 of this thread.
 
Species on the numbers being used for calculation?
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John says, "let's start with some assumptions".

He said "a reasonable hit rate...is 30%" per shot.

He assumed that it would take two or three shots to stop an attacker.

On the first number, that's about what we seen in law enforcement encounters. Remember, the defender is not shooing at a stationary target; he is not shooing at something at which he had been planning to shoot; he is going to have to shoot much more rapidly than most people do when they practice at the square range, and with far less time to get the gip and sight piste; he will certainly have been unpleasantly surprised and badly startled; he may well be frightened; and he may have to be moving.

On the second, keep in mind that bullets will be most unlikely to effect a rapid physical stop unless they strike at least one, and very probably more, of the various small critical anatomical elements hidden within a moving, turning, and opaque three dimensional envelope called the attacker's body. Not only are they hard to hit, the defender cannot even see them. The results will be a function of chance, and a number of hits may be required. Perhaps a rather high number, at the outside.

When I posted the links in Post 122, which contained the very same calculations, I suggested that if one does not happen to like those assumptions, one can run the numbers with different assumptions. That would probably be a very good idea, anyway--it would be eye-opening.

Of course, not every knows how to do that. but surely someone whom someone knows who does have that capability could be persuaded to help. That wouldn't require any knowledge of firearms--just statistics
 
I can not see any sense in doing calculations on how many rounds you might need! In a gunfight.

Carry a reliable 9mm pistol, double stack, with night sights, And an extra magazine, with NATO hardball, car doors, glass.

So Glock 19 4th gen, 15+1 and a Glock 17 spare, 17 rounds.

Some one taller than you, one round, top lip, 3 to 5 yds away. Eating supper? As the robber leans over you, in a Restaurant. : Retrieving your wallet!: Top lip.

More distance than that, a burst, upper chest. 2-3-4-5 rounds, 147g Ranger T. Seek cover.
 
The truth is the way some of you talk I am surprised you leave your house without an EBR of some sort with 200 rounds of ammo in mags on your hips.

Seriously, why do you care so much about what someone else chooses to carry for their own protection? I don't care if you choose to carry a 2 round .22 derringer or a Desert Eagle .50 AE semi auto. That has absolutely no bearing on what I will choose to carry and learn to shoot with confidence.
 
I can not see any sense in doing calculations on how many rounds you might need! In a gunfight.
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The only purpose, frankly, is to evaluate how well, using reasonable assumptions, our favorite or formerly favorite five or six shot pistol might be expected to serve us.
 
The only period, frankly, is to evaluate how well, using reasonable assumptions, our favorite or formerly favorite five or six shot pistol might be expected to serve us.
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Perhaps more time should be spent on situational awareness and trying avoid having to pull your pistol in the first place rather than imagining scenarios where you will play OK Corral and need 39 rounds to win.
 
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