"Armor piercing point"

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fishbulb

Joined
Sep 18, 2001
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I have seen a surprising number of knives advertised as having an "Armor Piercing" design.

Why?

If you want the knife for personal protection why would you be concerned with body armor. For a variety of reasons, very few crack heads and muggers wear body armor. About the only groups that wear armor on a regular basis are police and military, and stabbing them is generally a very bad thing.

It makes even less sense for a utility knife.

In any case, these knives usually have fairly a standard tanto or drop point design that doesn't look any different than the competition. This would indicate that the "Armor piercing" designation is meaningless.

Seems this is just a advertising gimmick. Is there any good reason for an armor piercing knife?
 
I think you're right about the designation being mainly an advertising gimmick. Very few people use knives for piercing stuff like oil drums, body armor, etc. There was a time when specially designed knives were made for penetrating chain mail, usually a triangular or rectangular profile blade which gradually widened so as to spread the links as you inserted the blade (you'd probably have to have the victim pinned though so he wouldn't wriggle around). Japanese katanas were purportedly designed to have a tip that was effective at piercing the armor of the day (a curved tip, not today's contemporary 'tanto' triangular tip).
 
is a term people use for a strong tip... I know it literally is supposed to mean to pierce armor, but in reality, what kind of armor and what kind of object being used varies the effect. A penny nail can be hammered through a kevlar vest, while the strongest and sharpest of knives may not be forced through a "rifle plate".

In the combat sense of the word, if one would come up against someone wearing armor, Kevlar or otherwise, the knife wielder should be aiming for a "soft target", or a spot not covered by armor, ie throat, eyes, nape ect. But then, if one were to choose to enter mortal combat against an enemy wearing armor with a knife, I would question his/her right to survive that fight and be allowed to pass on their genes.
 
a thin strong, but not too hard object is the best thing to penetrate armor...

Legend is that the Sykes-Fairbairn Commando knife was designed to be long enough to penetrate a winter "great coat" and uniform clothing of enemy (WW2 German) soldiers with enough blade left over to have lethal effect. Although the length was handy, it turned out that there are stories where these "greatcoats", after getting wet and freezing, broke, snapped and otherwise prevented blade penetration.
 
Crackheads and muggers do have armor! The forces generated in a thrust are nough to break the tip of of a poorly designed knife if it impacts bones just so. Similarly, hit a watch, or brick wall, or chain dangling from, the guy's wallet, or...

There are lots of bad things out there than can mess up a knife, so, am armor piercing tip would be a good thing on a defensive blade.

Exactly what is that? As was said before, it does depend on what people are wearing. But, the more steel you can get at the tip, the tougher it will be. However, it may not pierce liek a stilletto. I think that many armor piercing tips out there are probably o.k., but not stellar in their performance. Get a custom maker who knows what they are doing, and you'll get a serious performance-oriented tip.

As a side note, I find that it is the little things that make all the difference in the performance of a knife. Look at all of the thigns Ed Fowler demands that his "little" knives be able to do. It is amazing! I don't care for sheep horn and such materials really, but when I look at a Pronghorn, I see a knife that can do things knives twice its size can't. Why? The maker knows how to tweak the materials and the geometry. Find a maker who knows his tips and I bet you can get a super piercing and tough tip!

Edited to remove a word that really didn't belong!
 
It is all hype, Kevlar= 5 times stronger than steel.

New material is even stonger like 15 times stronger.
When we show vests we let people stab them and all it does is dull the edge real fast. like in 1 swipe.
 
????
I've always thought that ballistic vests are not necessarily blade-resistant too...
I remember on either TLC or Discovery that they were showing how they're trying to develope blade-resistant vest for prison guards because they're more than likely have to face shanks instead of bullets, and they mentioned that bullet-resistant vest does not always resist blades too.
I guess I haven't keep up with the bullet-proof vest stuff.
 
Aztacman,

when you show vests, do you slash with the knives or stab with them? What knives do you use?
 
I have always heard and been under the impression that while kevlar and other bulletproof materials are resistant to slashes they do little for stabs.
 
well... I have to say that the idea of the blade style being used as a 'marketing gimmick' may be true in some cases, but the only knife I have seen that uses that monicker is a MAYO TNT. I do not think in that case that it is at all 'gimmicky'. Tom Mayo has absolutely no need to have a 'gimmick' to sell his knives. I personally do not really like the aesthetics of that particular blade style, but keep in mind that LEO's and other servicemen purchase his knives as well as all of the rest of us. It looks to be a very functional blade for piercing purposes.

I have a friend who has some kevlar body armor, and when he got a new vest, we tested the used vest by putting it on a burlap bag stuffed with straw. We began buy shooting it at 10' with a .22, then .38, 9mm, .40 S&W, 10mm, .357 mag, .45 Long Colt, .44 mag, .40 AE, and finally .454 Casull. Then, we stabbed the upper portion to see what it would take to do any damage, and how much force was involved to pierce it. I wish I could have tested an 'armor piercing' blade, but I dont own one.

That vest was pretty tough. We decided to 'finish it off' when we were done 'testing' it by emptying a 40 round Ar-15 mag each simultaneously into it. :) That was fun.

Anyway, I do think that that blade style would serve a purpose... a cop or customs agent... etc... may be confronted with a person in some strange incident where the opponent is wearing body armor.... remember all the tv shows about the two bank robbers in L.A. who had fully autos and full on body armor? Well, if it depended on my life, I'd sure want the most effective stabbing/piercing tool available to me at my side at all times. Plus, Tom's could slash really well, too, I mean he is a sharpening specialist!

Like I said, I have not seen personally any other blades touted as 'armor piercing' but I am sure that some larger, cheaper companies use the term for marketing purposes as well.

-Dave
 
one has to understand how the "armor" works.


Armor is comprised of two types... Hard Armor and Soft armor.

Soft Armor consists of strong fibers knit into a fabric and then layered. The greater the number of layers, the more resistant to puncture the armor is.
Kevlar is abrasion resistant. The fibers are very strong. The weakness is in the weave which seperates, and in seperating, allows more abrasion in one spot... thus, slash resistant, but not very stab resistant...

Enter Spectra shield.... much more slash resistant, but it is also weaved differently. I believe that spectra shield is weaved in an alternating criss/cross pattern which resists slashes by it's superior material, and stabs by the weave which alternates the angles at which a stab would react to each layer of armor.

The force of the stab or slash as well as the number of layers have a direct effect on the chance of breaching the armor. Slashes will always have lesser chance due to a lesser amount of force applied directly against the armored target, and due to the natural behavior of the armor material. Also, the material of the knife as well as construction will contribute to whether or not the knife itself will fail before the breach is accomplished, as well as the amount of force needed to cause the breach, or point of failure. In a slashimg movement, the blade is constantly presented with new undamaged fibers to resist the blade... once a stab breaches a layer, that layer no longer presents any resistance against the blade.

Hard Armor...
Well, if you really have to ask why a knife won't penetrate 1/2 inch or thicker hardened steel or ceramic, I don't think you should be playing with knives... or forks....

Now, you would also have to have a hell of a lot of force to penetrate 18 or more layers of Kevlar (level 2a) and even more so for spectra shield...

Bottom line from a street knife-fighter I once knew... Body armor or not, aim for throat, eyes, nape or even armpit... even a hamstring...
 
Armor piercing tip means that it has a strong tip. I don't know that it would pierce armor. If it did how would you get it out?
 
Perturbed..

Very good points.. I am not sure which generation the vest we shot/stabbed/slashed was, It prevented penetration of the .22, the .38, the 9mm, and, surpisingly to me at least.. the .40 S&W. All the others just mangled it. We were using split point 'varmint rounds' in our AR's, that ripped it apart fully. It was difficult to stab through.. I guess that's why I would like to test an "armor piercing" blade.

I honestly do not think I'll ever have to pierce armor with bullets or blade... but I still enjoy keeping the tools that I need if it ever becomes necessary.

-Dave
 
Also,
Keep in mind that bullets and Blades, although they seem to to similar things to armor, they are in fact, very different.

In soft body armor, it is velocity, momentum and resistance to deformation of the projectile that bears upon it's effectiveness... A 9mm fmj travelling at 1190 (approximately standard velocity) will not defeat a 2a or greater, but pushed up to 1500 fps and it will cut clean through. A hollowpoint at that same speed will deform and spread it's energy over a greater area and may therefore not penetrate. Every impact will degrade the penetration resistance of the fibers around the impact area. One 9mm round will not penetrate, but the second one will have a greater chance. The chances will compound and eventually, a bullet of the same velocity and characteristic of the very first one (or even of a lesser potency) will penetrate the armor. Also, body armor is "worn" against a relatively hard object... a human torso or mannequin, clay, tree, ect. A free hanging piece of soft armor offers much less resistance to bullets so that projectiles rated to be stopped by the armor stand a greater chance of pass through them.

One more thing... almost any rifle round will pass through soft body armor like a hot knife through butter, any generation, any material. Rifle rounds (barring 22lr, and such rounds)travel anywhere from 2500 fps to 4500 fps. You need a 12 lb. strike plate to stop those.

You know, as a shooter and a knife collecter, it's a lot harder to hit a specific spot with a gun, than it is with a knife. I'd actually prefer to get into a knife fight with someone wearing heavy body armor. The opponent is thus encumbered and his range of motion is degraded.

I think what really applies is the Murphyish law...
If you're thinking about sticking someone who's wearing body armor, it isn't going to penetrate...

If you're wearing body armor and someone is looking to stick you, it's sure as hell gonna pentrate...
 
Hey, Melancholy..

GREAT points... I know a little bit of the physics involved here, but was a mere English Lit major... :)

I never intent to ever shoot or stab anyone... This was just a fun little 'test' we were both interested in seeing what kind of protection a Kevlar vest would provide... My friend Jake is ex-military, now in law enforcement... he an old issued vest... and we figured "hey, why not try to kill it?" OH< and kill it we did!

-Dave
 
Well, no one intends to do anyone harm... but it's a point to discuss as it does happen in the real world...

If the vest we're talking about is the standard PASGT flak vest, the camo one with two pockets and seperate shoulder pads, then they're approximately 16 laters of raw kevlar. Minimally 2a type protection.

I used mine as a bullet stop for shooting in my basement... each panel stopped about a 50 .22 rounds before it got to the point where they started punching through.
 
john greco makes a tanto 'penetrator' i think he calls it, saw it on blade art, i have a tanto 5.5" that is pictured right below it, the 2 look pretty similar, dont know why 1 would be a penetrator over the other......
 
Originally posted by AZTACMAN
It is all hype, Kevlar= 5 times stronger than steel.

New material is even stonger like 15 times stronger.
When we show vests we let people stab them and all it does is dull the edge real fast. like in 1 swipe.
Click to expand...

Strength does not always equal resistance. Just because kevlar is stronger than steel doesn't mean it will stop a blade.

A nylon rope can be stronger than a chain, but which one can you cut through with your blade?
 
MelancholyMutt: you took the word right out of my mouth... Spectra is the stuff that I saw on a table in a recent gun show (rather crappy IMO) that said would offer blade-resistance.
There were combo vest where there are kevlar and spectra together.
When any object's speed doubles, the energy is 4x as much as before. A rifle bullet is bound to go through 16-18 layers of Kevlar because of its raw speed, not to mention the FN Five-seveN and the P90, which is a smaller arms for militaries to do short work with body armor ;)
 
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