The Surprisingly Solid Mathematical Case of the Tin Foil Hat Gun Prepper | Hacker News Reader

The Surprisingly Solid Mathematical Case of the Tin Foil Hat Gun Prepper

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36 pointskorethr20 comments

The problem I have is when people say that they need an ar15 (or any automatic rifle) to defend themselves, family, or to protect their property. I’ll put the last out of the way first: theft is not a capital offense, so someone stealing your car is not a reason to shoot them.

For the other options a automatic rifle is an poor choice. No rifle has any difficulty going through dry wall or cladding, so if you’re in any urban or suburban location your odds of hitting someone else (like your family members or neighbors) is reasonably high.

For rifles like ar15s you’re firing bullets that will go through whoever you hit, if you do hit them. Given they’re automatic, you’re presumably planning on firing many rounds, which further increases the risk to others.

Presumably part of the reason to want an automatic weapon is to manage missing the target - that’s why soldiers have them. Of course a soldier has another thing a preppier doesn’t have: all the people in one direction are valid targets.

This isn’t the case if you’re not on a battlefield.

Then there’s the practicality of the “protect my family” argument. For that to be useful your gun (of any kind) has to be loaded and easily accessible - which is a good way to add to the statistics of children accidentally killing themselves or others with their parents guns.

Finally - if you /really/ want to have a gun to “protect your family/self” use a shotgun. There’s less harm to people who aren’t directly in the line of fire, the effective distance is vastly shorter so less risk to people in other rooms, and you don’t have to be as good at aiming.

High powered automatic rifles don’t belong off a battlefield.

An AR15 is a semi-automatic rifle. An M-16 is an automatic rifle and can't be owned by a civilian. A semi-automatic firearm means to fire two rounds you must pull the trigger twice, to fire three you pull three times etc. An automatic rifle will fire as long as you hold the trigger back.

An M-16 will expend it's 30 round magazine in about 3 seconds in full auto. Full auto is rarely used and when it is it's mainly for suppressive fire, which generally means to keep the enemy's head down while your squad moves to better cover or firing position.

Oh, one more thing, at house distances shotguns most certainly have to be aimed.

I used to live in east texas and we have wild hogs that show up in packs of 30+ that will absolutely destroy your property. An AR15 with high capacity magazines is very needed in that situation.

Minor detail about theft and the law: in most states you can't shoot a thief. Favoring thieves over their victims is not universal law in the United States.

I have a great example for your "For rifles like ar15s you’re firing bullets that will go through whoever you hit" comment. A young man used his father's AR-15 to kill 3 intruders (2 of them armed) with just 2 bullets. One of the shots did in fact go through the person hit, which turned out to be beneficial. Here you go:

https://www.nbcnews.com/news/us-news/oklahoma-man-uses-ar-15... https://www.washingtonpost.com/news/morning-mix/wp/2017/03/2...

And yes, "all the people in one direction are valid targets" did apply, as it normally would.

>Finally - if you /really/ want to have a gun to “protect your family/self” use a shotgun. There’s less harm to people who aren’t directly in the line of fire, the effective distance is vastly shorter so less risk to people in other rooms, and you don’t have to be as good at aiming.

This! And I think there's another aspect of shotguns that makes them far better suited for self-defense: the sound of just pumping a shotgun is LOUD. It's absolutely a "warning shot" in and of itself. If you're looking for a self-defense gun, get a pump-action shotgun. If that sound alone isn't enough to make any intruders scatter like cockroaches, only then do I feel like deadly force would ever really warranted, because no bumbling hapless robber just out to steal your TV is going to stick around after hearing it.

This entire comment betrays an ignorance of the AR-15 and the ballistics of the common loads of its most common chambering, and as well as actual military combat doctrine.

> I’ll put the last out of the way first: theft is not a capital offense, so someone stealing your car is not a reason to shoot them.

You are absolutely correct about that. But it is absolutely reasonable to think somebody breaking into your house or car while you are in it may well have lethal intentions toward you. The courts have ruled on this more than once.

> ar15 (or any automatic rifle)

Back when revolvers were the most common handgun type, "automatic" referred to those fancy new auto-loading kind. Some hundred years later, "automatic" used in reference with a firearm means a firearm that not only self-loads after firing, but will then self-fire so long as the trigger remains depressed. The AR-15 and other rifles in the family are semi-automatic. One trigger pull, one shot. That might seem like a niggling distinction, but it's not. "(fully-)automatic" and "semi-automatic" are terms of art with regard to firearms, and have specific meanings. An automatic M-16 can fire about 600 rounds a minute and empty its magazine in about 3 seconds. A semi-automatic AR-15 can do about 60 rpm at max, and can empty its magazine in about 30 seconds, assuming the shooter can keep up that trigger speed for that long (most can't).

> No rifle has any difficulty going through dry wall or cladding, so if you’re in any urban or suburban location your odds of hitting someone else (like your family members or neighbors) is reasonably high.

This is true of any firearm, especially at indoor urban distances, But counter-intuitively, it's worse of handguns and shotguns than it is of a light rifle like the AR-15.

The AR-15 is most commonly chambered in the medium-powered .223/5.56mm round, which can be loaded in different configurations with varying trade-offs between fast & light loads (shorter bullet, more powder) and slower & heavy ones (longer bullet, less powder). A faster, lighter projectile is going to lose more of its energy upon penetrating a wall than a slower & heavier one will. The projectiles from a handgun or shotgun are much slower & heavier than the common loads of .223/5.56mm. I've read a few articles about this, which involved tests setting up simulated walls, and seeing how many walls the projectiles go through or how less far they go into a block of ballistic testing gelatin after a wall. Of all the various firearms one might chose for home defense, an AR-15 loaded with a 45 or 40 grain load is the least dangerous to those in adjacent rooms or structures.

> For rifles like ar15s you’re firing bullets that will go through whoever you hit, if you do hit them.

Just like with handgun rounds, one can buy rifle rounds loaded with bullets that expand or fragment upon impact, increasing the amount of energy they transfer to the target, and reducing the retained energy of anything that continues through the target or wall, thereby reducing the danger to others nearby.

> Given they’re automatic, you’re presumably planning on firing many rounds, which further increases the risk to others.

Anything worth shooting is worth shooting twice so it stops doing whatever it was that made it worth shooting as immediately as possible. And since an AR-15 isn't automatic, one is far less likely to do an adrenalized magazine dump that sprays bullets everywhere, and more likely to place one's follow-up shot as accurately as the first.

> Presumably part of the reason to want an automatic weapon is to manage missing the target - that’s why soldiers have them. Of course a soldier has another thing a preppier doesn’t have: all the people in one direction are valid targets.

> This isn’t the case if you’re not on a battlefield.

Automatic fire is used less on a battlefield to make up for misses and more as suppressive fire, to keep enemy heads down so your fire team or another fire team can move with less risk. When it's time to take actual shots at actual targets, semi-automatic fire is used. And soldiers on a battlefield absolutely do have to worry about potential friendlies or innocents lying in the same direction as enemies.

>Then there’s the practicality of the “protect my family” argument. For that to be useful your gun (of any kind) has to be loaded and easily accessible - which is a good way to add to the statistics of children accidentally killing themselves or others with their parents guns.

A rifle (or any gun) can be loaded and easily accessible to the one wishing to protect his family without making it readily available to any child to grab. And in all the rifle-owning households I've personally observed, the children are taught from an early age not to try get at the gun, and then quickly taught to be responsible with them as soon as they're old enough. Oh, I'm well aware of the resourcefulness and disobedience of children; I was quite that way myself. But even at single-digit ages, a child can understand the responsibility that comes with handling a firearm. In rural areas it's not uncommon to see kids with their own rifles. It's largely the kids who grow up in ignorance of firearms that can't seem to be responsible with them. And for the kids who aren't old enough to grasp that yet, it's the duty of the adult to supervise the child. An adult who can't do that isn't mature enough to have a child or a firearm.

> Finally - if you /really/ want to have a gun to “protect your family/self” use a shotgun. There’s less harm to people who aren’t directly in the line of fire, the effective distance is vastly shorter so less risk to people in other rooms, and you don’t have to be as good at aiming.

I've taken on the myth of less danger to those not in the line of fire above, but I'd like to additionally point out that at the distances one is likely going to be dealing with in a protect-your-family scenario, you still have to aim that shotgun and aiming is going to be a wash between the two. If you can't hit a target at 5 or 10 feet with a rifle, you're probably going to have an even harder time controlling the shotgun's even greater kick, and be even more dangerous to those not immediately in the line of fire than implied in your paragraphs above.

> High powered automatic rifles

An AR-15 is not a high-powered rifle. The most common .223/5.56 chambering is considered an "intermediate" power round, and is not legal for shooting even smaller deer (most common North American species have roughly the same mass range as humans). If you spend some time listening to soldiers who've been deployed, you might hear them bitching that the 5.56 round is underpowered, and it would have been better for the the US to have stuck to a rifle that used a full-size round, like the M-14. If we were talking about people keeping M-14s, or big-game rifles for home defense, I might agree with some of your points above. But the AR-15 is anything but a high-powered rifle.

Why do I harp on this? It's not because I'm a gun nut and someone was wrong on the Internet. As hackers, we (quite rightly) get pissed when we see people spouting incomplete, wrong or misleading things about technology, and then using said bogus points to advocate bad or harmful policies or ideas. It is natural and right to speak up against such false or misleading things and advocate against harmful policies. But there's a flipside to this, if we do not want others to abuse and conflate our terms of art to prevaricate or dissemble, if we do not want policy based upon irrational emotion and and half-truths to hobble our ability to work, then we should not do the same regarding other fields, and have a duty to call out our own when we see it being done.

@olliej. I think you are reaching some interesting conclusions. However your foundational facts, are a bit off - -and that's, perhaps, why your conclusions end up off.

I invite you to review some materials with regards to

a) Difference between automatic and Semi-automatic rifle

https://www.dailyshooting.com/full-auto-vs-semi-auto-gun/

b) What considered to be more lethal effective fire patterns (it is not pray and spray afforded by fully automatic, it is burst -- but burst firing weapons are not available to US public (as they are considered automatic weapons) )

https://www.reddit.com/r/guns/comments/2yvii6/what_happened_...

c) Various approached to avoid overpenetration

(this is something widely taught to US law enforcement)

In short, AR-15 is an example of a 'modular platform' Just like in some programming languages you can replace Garbage collector or memory allocators. In Ar-15 you can replace barrel and bolt to leverage different caliber ammunition , and often keep same magazine.

The calibers that do not shoot as far, and over penetrate less are .300 blackout and .458 SOCOM (or wildcats like .338 Spectre). Usually they have fatter cartridge case (so one will have fewer of them in the standard capacity AR magazine). They will have heavier, often softer bullet, and will fly less distance than the standard .223 round.

Prepers, often do not just save ammunition, but also ammunition components that lets them reload a spent case with new powder + primer + bullet.

Bullet designs are a bit of a 'science' on it is own - -there are the ones that penetrate, the ones that do not , the ones that designed to mashroom, and so on. As an example, a so called hollow point bullet will often mushroom before it over penetrates.

Ability to use multiple calibers, depending on the situation is one big reason why ARs valued more than that semi-auto AKs for example. Different calibers allow a prepper to hunt different types of game at different distances, defense, reuse neighbor's ammo, etc.

d) Prepping in concert with your neighbors (not against them).

https://www.backdoorsurvival.com/importance-of-community-and...

many in prepping communities dismiss 'single person or family compound strategy' and instead advocate an synchronous community prepping, as that's considered much more sustainable long term.

e) Theft is not a forcible felony, so lethal force cannot be used to defend against theft and 'Stand your ground laws do not apply at all.

A person who would shoot at a running thief who is stealing a car in a driveway, or a axe from your store, will end up in jail.

Forcible felonies usually include (example Florida) :

https://www.jacksonvillecriminalattorneyblog.com/what_is_a_f...

– Kidnapping

– Murder

– Manslaughter

– Sexual Battery (Rape)

– Arson

– Treason

– Robbery

– Burglary

– Carjacking

– Home Invasion

– Aggravated Battery

– Aggravated Assault

– Aggravated Stalking

-Any other felony that involves the use or threat of violence against any person

Also important that the person claiming self defense was NOT an initial aggressor.

For example, if you are at a restaurant with your spouse, and somebody is insulting her/him. You stand up and start arguing with that person, may be push him. Then he runs at you with a chair or knife, you shoot him. You will likely be convicted and go to jail because you were aggressor as well. If on another hand you stood up, called police and started walking away from the situation, and then you were attacked and defense your self -- the legal claim for self-defence could stand (I am not a lawyer).

This is why some often say that 'Armed society is a polite society'. Legally armed civilians will rarely advance into a confrontation can be simply avoided.

In terms of rifles, the relevant calculation would be more along the lines of the probability of a calamity happening and the rifle coming in handy, versus the probability that the rifle is abused in some way (stolen, harmful accident or suicide). I generally believe that those with prepper mentality downplay the latter probabilities because those are more under their control. Preppers tend to be control freaks, and worry much more about exogenous risks than risks they feel they can personally manage. However, this is likely fallacious reasoning. Everyone runs a risk of a mental/emotional break, or an act of carelessness leading to an accident.

Building a house doesn't cause a flood plain to flood (hopefully!), but adding lots of guns to a country sounds like it should have an effect on the number of revolutions, be it up or down.

It's also not clear whether prepping will have been a good thing or a bad thing in the event of a revolution. You're arguably more likely to shoot yourself with a gun than to shoot someone else, even during a period of civil unrest; you're painting a target on yourself in the eyes the government; some measures you could take, like owning a gun, fortifying your house, firing your rifle at 7AM, owning an aggressive dog, or kicking people off your property, will socially isolate you from the same neighbours you'll need to cooperate with in the event of a disaster; and in general it's not clear why a prepper is more likely to survive than a small-scale farmer, given that the latter owns and regularly uses guns, produces food, is used to intermittent hardship and long days, lives in a rural area, and gets along with the government and their neighbours better.

> Building a house doesn't cause a flood plain to flood (hopefully!), but adding lots of guns to a country sounds like it should have an effect on the number of revolutions, be it up or down.

Intuition would imply that, but I'd say there's not enough data to really say. There's countries with less civilian firearm ownership than the US, older and younger both, with more frequent violent revolution, and less frequent violent revolution. There's too many differences in culture, demographics, economics, and probably other factors I'm not thinking of, that even if increased rates of firearm ownership had an effect on the number of revolutions, that effect is utterly swamped by other factors.

Your latter paragraph seems to imply you have a different idea of what preppers do than I do. When I hear the word "prepper", I think of a person who stockpiles non-perishable foods, stockpiles ammo, owns multiple firearms and practices with them regularly, and drills both evacuation and hunkering-down scenarios with their family. I'm not sure where alienation of the neighbors enters in here, as nothing in preparing for a disaster requires or recommends having pre-established enemies living <100 feet in any direction from where you do.

> Building a house doesn't cause a flood plain to flood (hopefully!), but adding lots of guns to a country sounds like it should have an effect on the number of revolutions, be it up or down.

As someone who lived in Houston during Harvey, you're dead wrong. Near where I lived used to be fields which soaked up water. Now it's concrete, which doesn't. You can tell the difference during heavy rains.

No.. surprisingly naieve stats. There is no causal linkage between violent events beyond the business cycle, so his math on averages is observational not deterministic.

The watts riots are not linked to no blood for oil. You can't throw a line between them and plot median interval before violence breaks out like that.

Seriously: prepping makes sense if you are risk averse but you don't go from hydrology flood risk to vampires in one throw.

He shouldn’t ignore the minor events and only calculate the grand events. For instance the Brits attacked us in 1812, Mormons slaughtered settlers 59 years later, Mexican revolutionaries raided borders, Johnstown was flooded, Pinkerton shot strikers, we had draft riots, Martin Luther King’s assassination set off urban riots as did the Rodney King trial, if you were black in the South your life was in peril, Hurricane Katrina placed folks in desperate straits with an already corrupt police force refusing to help and actually hindering self protection to the point of openly shooting people for no god damn reason, almost forgot Kent State, the armed forces killing citizens. The whole fucking enterprise is corrupt. The unibomber may have been on to something ala John Brown whose body lies moldering in the grave.

What really scares me is, the same argument applies to war- and because the world is loaded with nuclear weapons, when it finally happens it’s likely to go nuclear. Nukes are one class of weapon where in the aggregate their existence is an existential threat to mankind.

For this reason, a long term goal of mine is to move to New Zealand. In retrospect, we probably had a more likely chance than not of the Cold War turning nuclear. There were several extremely close calls averted by dumb luck.

In the next Cold War, especially in light of instability from climate change, we might not be so lucky.

Yeah, New Zealand is probably the right place- isolated, Southern Hemisphere so there’s less fallout, English speaking, temperate. Still, in the worst case scenario there will be about a billion starving people flooding down from various places in Asia so even there you’re not really safe. I’m putting my efforts into political organizing as my strategy, I think that there really isn’t any good course of action in the event of nuclear war and prevention is the only good option.

Prepping might give you an advantage during a small interruption in services. Any prolonged disruption and it does you little good, unless you’re far removed from everyone and no one knows you have some dedirable goods. Maybe if you live in decommed silo. Otherwise, unless you have a militia with you, who will needs lots of food and other things, no matter how well you’re armed and stocked, you’ll be overwhelmed by others you’re not sharing with. So it may help in minor cases, but definitely not in catastrophic cases, except it may help delay the inevitable a little bit.

Financial calamity prevented on every down turn year turns a normally unstable situation into a financial bomb. Markets are always unstable and they always correct. Thwarting the ultimate course of corrections ensure that eventually a correction comes that cannot be stopped or softened and the magnitude isn’t a calamity. It is a cataclysm.

I think of the example of holding a beachball under water. The farther under the water you hold it, the more explosively it will leap out of control when you do let it go.

The example is broken.

Air is much more compressible than water. Pressure will be almost a linear function of depth because water isn't very compressible.

From the depth at which pressure is equalized inside and outside the beachball, until reaching the depth at which the ideal gas law becomes inaccurate, the volume of the beach ball will be simple function of depth. Doubling the depth will halve the volume. Beyond that, the volume will collapse faster, until the air becomes a supercritical fluid with density similar to that of the water.

In any case, the ball shrinks as you go deeper.

Buoyancy is roughly the density of the water times the volume of the ball. (the air inside is of trivial mass) The water density doesn't change much because water is not very compressible, but the volume of the ball decreases. This reduces the buoyancy force.

Suppose the ball is made of PVC, which sinks in water. Once the air has been pretty well compressed, the average density of the ball (air and PVC) will exceed that of water. The ball thus sinks.

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