# Ponder the Unthinkable (pt39) Armor



## Winston (Oct 22, 2018)

If you ever catch yourself using the phrase “bullet-proof vest”, slap yourself.  
There is no such thing.

Body Armor falls into two distinct classes of protection, hard and soft armor.  Neither is bullet-proof.  Each has it’s advantages and disadvantages.  So, if you’re talking or writing about armor, and you tell a story about a Kevlar vest stopping a rifle round, congrats.  You made yourself look like an idiot.

If you don’t want to sound stupid, or more importantly, are considering purchasing body armor for yourself, read on.  

“Know your enemy, as you know yourself”, Sun Tzu.
First, just like buying a car, or a pair of shoes, what do you need body armor for?  
A full size truck makes for a lousy commuter car, and high heels are crummy track shoes.  
The task at hand is protection.  And the threat is overwhelmingly likely to be a pistol.  Of all US firearm owners, two-thirds only own a pistol.  Rifles make up a very small percentage of all firearm assaults.  So, there is your likely enemy.  The handgun.  

Both hard and soft armor will defeat a pistol round.  But hard armor is heavier, rigid and bulky.  Soft armor weighs less and is flexible.  Most Law Enforcement patrol officers use Kevlar vests for daily on-the-job use.  SWAT units put on the heavier hard armor for special circumstances.

Conversely, US soldiers serving in Iraq and Afghanistan quickly learned that (in the early 2000s), soft Kevlar vests did nothing to stop soldiers armed with rifles.  Within a few years, most front-line troops were issued hard “plate” armor (usually ceramic).  It saved lives, but contributed to numerous orthopedic injuries due to the increased daily combat load.  

As you can see, there is no free lunch.  There is a trade-off for weight and protection.  
Unless you’re going to war, soft armor makes sense for most people.  

But if you’re trusting your life to these vests, don’t you want to know how they work?  Sure you do!

Soft armor usually consists of layers of an aramid fiber such as Kevlar, Spectra or Dyneema.  The fibers are woven together in a dense mesh, each fiber supporting the surrounding fibers.  This is what gives the material it’s strength.  When a projectile hits this mesh, the energy is transferred simultaneously to all the adjacent fibers, slowing the projectile.  Numerous layers are used because it is common for the first few layers of Kevlar to break and rip as they slow the projectile.  Depending on the bullet, anywhere from 5 to 10 layers of Kevlar will be penetrated prior to the vest stopping the round. 

Here’s that trade-off again.  A thinner, concealable vest such as a IIA or II may only have 13 to 15 layers of Kevlar.  A bulkier Level IIIA usually has 20 layers, or double the average penetration resistance.  It comes down to literally what you’re most comfortable with.  

But before you settle for a vest with only 13 layers, remember this.  After the panels have been compromised, they lose resilience exponentially.  When the fibers are torn, they no longer mutually support each other as efficiently.  So, even if you get shot in a different part of the vest, each successive hit weakens the panel overall.  If you’re “planning” on only getting shot once or twice, the lighter vest should work.  Should.  

Here are two additional factors:  Blunt force trauma an knife attacks.  If you are hit while wearing a vest, you will feel it.  Bruising is common, and often a rib may be broken.  Remember, the Kevlar works by absorbing the bullet energy, but it does flex inward… toward you.  Also, most vests ironically do not protect against stabbing.  Corrections officers do have specialty vests for that, but it’s not the standard Kevlar ballistic type.  

So, why not just “bite the bullet” and wear hard armor?  It stops all pistol rounds, most rifle with full stab protection and limited trauma from impact.  Sounds like a winner!  Again, aside from the weight.  

Typical hard armor is a special metal called AR500 steel, or ceramic plates.  Steel has one huge advantage:  Multiple hit capability.  You can basically shoot at a steel armor plate all day long, and it will not fail.  Ceramic plate is lighter than steel, but it’s a “one and done” deal.  The ceramic cracks, and it’s finished.  Ceramic plates can also be damaged by rough handling.  This means you better be careful with them, and / or inspect the ceramic plate prior to use.  Sounds like a real hassle just to save some weight.   

Steel plate has one big down side:  Spalling.  When a bullet traveling 2800 feet per second comes to an instant stop, that’s a lot of energy.  Often, the bullet shatters and fragments travel in all directions.  Including into your legs, arms and neck.  All reputable AR500 plate distributors offer a “base coat” of Line-X type absorbent material. I wrap mine in a couple layers of Kevlar as well.  Even a nick in your femoral or jugular will ruin your day.  

I specifically discussed armor you can buy, and that works.  YouTube warriors and Junior Doctor Protons are probably screaming “Non-Newtonian Fluids!” and “Carbon Fiber Nanotubes!”.  I actually own a non-Newtonian riot gear set.  It’s made by a company called D3o, French cops used them.  Here’s the lowdown:  The material doesn’t harden-up quick enough to provide ballistic protection. Blunt force?  Hell, you could smack my arm with a 2X4, I wouldn’t feel it.  I just won’t be deflecting bullets like Diana Prince.  

As far as carbon fiber nanotubes, they look very promising.  Kinda like 3D aramid fibers.  But at this moment, they are God-awful expensive.  And there are some developmental hurdles to jump.  May as well save your money and wait for the personal force field.  

There’s one new tech I’m on the fence embracing: Ultra-high-molecular-weight polyethylene, or UHMWPE.  Basically, the idea is to build-up enough Dyneema fibers into a ridiculously thick plate.  It’s light weight, and provides protection from rifle class threats.  I just don’t see how you can shoulder your own rifle while wearing one.  And, like all aramid fibers, it is not multi-hit rated.    

In a pinch, you could always shove some aluminum 6061 T6 in your pockets and hope for the best.  Seriously, .188 thickness will stop a .22 caliber dead in it’s tracks.  
But I digress…

For most of you, just buy what the cops use.  And why should you, a private citizen, do that?
Think of how many homeowners arm themselves to challenge a burglar. They grab a gun because they expect the bad guy to have a gun.  If HE has a gun, why wouldn’t you armor-up before challenging him?  Kind of a no-brainer.  

I own a couple of each (just not ceramic, because cracks kill).  Does that make me a nut?  Yep.  But not a bullet proof nut.  Just a well protected one.


----------



## Plasticweld (Oct 23, 2018)

I saw only one nit._ Blunt force trauma an knife attacks. _Missing d. 

I had a Second Chance vest I wore for a few years.  Great in cold weather, uncomfortable in the heat or humid times of year. 

Great point about them not being much good against a blade attack, something most don't consider or realize.


----------



## Winston (Oct 23, 2018)

Plasticweld said:


> I saw only one nit._ Blunt force trauma an knife attacks. _Missing d...



Well, there is also a missing "h" in my title (I can't edit that).
But it works OK the way it is.  A round impacting metal does make a "tink" sound.


----------



## Plasticweld (Oct 24, 2018)

I fixed that for ya :}


----------



## Olly Buckle (Oct 24, 2018)

Interesting, kind of glad I live in a society where firearms are a comparative rarity still. I had a winter coat once from Japan that had a middle layer made from an unwoven mix of cotton and silk, the long silk threads stop the cotton from 'bunching', I was told the combination will also stop a knife blade, never had the need to try it though


----------



## Winston (Oct 24, 2018)

Olly Buckle said:


> ...the long silk threads stop the cotton from 'bunching', I was told the combination will also stop a knife blade, never had the need to try it though



The first lightweight body armour (circa 1900) was in fact made with silk.  But large quantities of silk are expensive, and it is difficult to work with.  I know it can be effective against projectiles, but I would not bet my life on it working in a knife attack.  
If you don't mind adding a few pounds to your coat, just add a few layers of very tightly constructed Kevlar sheets.  Then, treat your coat with shear thickening fluid (STF), a non-Newtonian fluid that hardens as the blade penetrates.
Or, stay away from places you might be stabbed.


----------



## sigmadog (Oct 25, 2018)

Winston said:


> Or, stay away from places you might be stabbed.



That's my philosophy. Also try to avoid areas I might get shot. Even though I have a concealed carry permit and am usually armed, getting in a shoot out is not exactly "Plan A". Hopefully situational awareness will allow me to avoid those situations. But who am I kidding? I rarely leave my secluded mountaintop compound anyways.

Interesting article. It reinforces some information I had heard before in a clear way.


----------



## Olly Buckle (Oct 25, 2018)

Winston said:


> Or, stay away from places you might be stabbed.



That is pretty easy in rural East Sussex  I didn't get the impression that it was simply the silk, but the mixture of unspun silk and raw cotton that would stop a blade, but I wouldn't want to bet my life on it either, as you say best to avoid the possibility of finding out.


----------

