50 bmg protection at 4 pounds?

[SirFlamenco]

Hi everyone, first post here 

 

I stumbled across this video : 

 

 

 

It’s super dense polyethylene with a neutral buoyancy core for impact resistance. It weights only 4 pounds, so for weight effiency it’s around 3 times better than ar550 and 4 times better than other ceramics ballistic plates, AND that’s while including the water, which I doubt add any bulletproof capabilities. 

 

Is it just me or does it sound a bit fishy?

[A_Mysterious_Stranger]

Well  it's UHMWPE so I don't think it's subject to plugging the way a steel plate would be.  It's also a lead core rather than something harder which I think affects penetration..   Also there's ballistic limit - stopping a single round of a single type/weight at a given velocity is great, but how repeatable is that fact?  Can it stop such a round 50% of the time  (v50) or almost every time (V0)?    There's also the backface deformation (hard to judge but at least 25-30mm?).  And a 4lb plate hit by a 750 grain round moving at 2400 fps is going to impart considerable energy and momentum to the body which isn't likely to be any kinder (ESPECIALLY with the aforementioned backface deformation.) 

 

Reminds me of some of the claims you used to hear about Dragon Skin.  There was a similar 'test' done for something called Kryon Terminator some years back which also claimed to stop .50 cal (though it was unclear whether that had any relevance to body armor.)  It's entirely possible, but with body armor there's always more to it than 'can it stop X round' (again Dragon Skin.)

[Collimatrix]

The water might do something.  In tanks there are armor arrays that double as fuel tanks (or are they fuel tanks that double as armor arrays?) where the diesel fuel is arranged in a container such that it will create pressure waves that are disruptive to threats that penetrate the fuel tank.

It is my understanding that this trick has to be tuned to a specific threat, with array performance falling off the less similar the threat is to what it's designed for.

[Wiedzmin]

^10 meters

 

there was a tests with  polyethylene, for buletproof vests, it was able to stop AKM 7,62x39 point blank(10 meters), but when bullet velocity drops to distance of 300 meters , bullet went through 

 

300 meters^

don't know if it was problem with certain polyethylene or it correct for any sort of polyethylene

[Bronezhilet]

Pictures don't work for me.

[Toxn]

Nor me.

[Krieger22]

Doesn't work for me either.

 

I'd like to see how the energy is dissipated. The bulge on the reverse side suggests that it's still pretty concentrated, which would be pretty bad news for one's internal organs anyway...

[Wiedzmin]

updated 

[Toxn]

18 hours ago, Wiedzmin said:

updated 

Thanks.

 

Having seen the images now, all I can say is that that's a very thick sheet of UHMPWE - in the order of 25-30mm which gives it an areal density of 23.6-28.3kg/m^2.  It's still a huge saving over an equivalently-protective steel plate (47.1kg/m^2 for a 6mm plate) though.

 

I suspect that this sort of thing works best as a backing for a hardened strike face, as it seems to need a certain level of bullet deformation to work properly. Which probably argues for something more along the lines of a 1.5mm hardened steel/4mm ceramic plate up front, backed with a 15-20mm sheet of UHMPWE, as your optimum. 

 

Edit: after thinking for a bit, I remembered that you'd probably want to put any ceramic elements about 1/5 to 1/3 of the way in to maximise their efficiency.

[Toxn]

On ‎7‎/‎25‎/‎2018 at 12:36 AM, SirFlamenco said:

Hi everyone, first post here 

 

I stumbled across this video : 

 

 

 

It’s super dense polyethylene with a neutral buoyancy core for impact resistance. It weights only 4 pounds, so for weight effiency it’s around 3 times better than ar550 and 4 times better than other ceramics ballistic plates, AND that’s while including the water, which I doubt add any bulletproof capabilities. 

 

Is it just me or does it sound a bit fishy?

 

Having watched the video, I will note that the guy doing the shooting is using a Hornandy A-Max bullet. This means that the tip is plastic and the round is designed to expand when it hits something. Which, from the other tests, seems to be the perfect thing to shoot at this particular configuration of armour. I'd expect ball and AP cartridges to pass right through.

 

I'm also not sure why you mention water, as the armour has none. Rather, UHMWPE is a little bit less dense than water, so this thing would float.

[Wiedzmin]

one more

[Sturgeon]

14 hours ago, Toxn said:

 

Having watched the video, I will note that the guy doing the shooting is using a Hornandy A-Max bullet. This means that the tip is plastic and the round is designed to expand when it hits something. Which, from the other tests, seems to be the perfect thing to shoot at this particular configuration of armour. I'd expect ball and AP cartridges to pass right through.

 

I'm also not sure why you mention water, as the armour has none. Rather, UHMWPE is a little bit less dense than water, so this thing would float.

 Fitty cal AMAXes have aluminum tips.

[Ramlaen]

that's a big nope

 

[Toxn]

1 hour ago, Ramlaen said:

that's a big nope

 

Better than the alternative, I guess.

 

I agree that I'd want something more rigid though. Having your liver explode could seriously ruin your day.