Jump to content
Sturgeon's House

50 bmg protection at 4 pounds?


Recommended Posts

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?

Link to comment
Share on other sites

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.)

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

DT9NsRz.jpg

O4qq2p6.jpg

^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 

d3bqkFM.jpg

 

300 meters^

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

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

  • Similar Content

    • By Beer
      I haven't found an appropriate thread where to put some interesting rare stuff related to WW2 development, be it industrial one or makeshift field modifications. 
       
      Let's start with two things. The first one is a relatively recently found rarity from Swedish archives - a drawing of ČKD/BMM V8H-Sv tank. The drawing and a letter was found by WoT enthusiasts in Swedish archives in 2014 (the original announcement and the drawing source is here). The drawing is from a message dated 8th September 1941. One of the reasons why this drawing was not known before may be that the Czech archives were partially destroyed by floods in 2002. Anyway it is an export modification of the V-8-H tank accepted into Czechoslovak service as ST vz.39 but never produced due to the cancelation of all orders after Münich 1938 (for the same reason negotiations about licence production in Britain failed). Also later attempt to sell the tank to Romania failed due to BMM being fully busy with Wehrmacht priority orders. The negotiations with Sweden about licence production of V8H-Sv lasted till 1942, at least in May 1942 Swedish commission was present in Prague for negotiations. The tank differed compared to the base ST vz.39 in thicker armor with different front hull shape (armor 60 mm @ 30° on the hull front and also 60 mm on the turret; all sides were 40 mm thick). The tank was heavier (20 tons) and had the LT vz.38 style suspension with probably even larger wheels. The engine was still the same Praga NR V8 (240-250 Hp per source). The armament was unchanged with 47 mm Škoda A11 gun and two vz.37 HMG. The commander's cupola was of the simple small rotating type similar to those used on AH-IV-Sv tankettes. It is known that the Swedes officially asked to arm the tank with 75 mm gun, replace the engine with Volvo V12 and adding third HMG to the back of the turret. In the end the Swedes decided to prefer their own Strv/m42. 

      Source of the drawing
       
      The second is makeshift field modification found on Balkans. It appears Ustasha forces (and possibly some SS anti-partizan units) used several Italian M15/42 medium tanks with turrets from Pz.38(t). There are several photos of such hybrids but little more is known. On one photo it is possible to see Ustasha registration number U.O. 139.

      Few more photos of such hybrid.
       
      It appears that the source of all those photos to be found on the internet is this book, Armoured units of the Axis forces in southeastern Europe in WW2 by Dinko Predoevic. 
       
    • By pizza654
      Hi as most of you know who are in the gun community a bunch of AR 70/90 kits came into the country and theirs still no barrels or receivers in production. Since I cant find anything I decided that I'm just going to make my own barrel and I've found the measurements from a guy on reddit who lives in Italy. 
       
      https://imgur.com/gallery/WUtxuAP
       
      https://imgur.com/gallery/1ydhDUS
       
      As I was getting the measurements a curiosity ran through my head, how do you mathematically figure out the proper diameter of the gas port hole for the gas block in the barrel?
       
      Much help will be appreciated! 
       
       
    • By Curly_
      This came up in a recent discussion I had with a friend over Discord, concerning a hypothetical near-peer conflict (particularly in an urban environment). My friend is of the belief that in such a conflict there isn't no reason to field any small arms (not just service rifles or light machine guns) in anything larger than something like 5.56 NATO, the rationale being that a.) you can carry more of it compared something like 6.5 Creedmoor or 7.62 NATO, b.) you're mostly going to be using it suppressing the enemy so that you can drop high explosives on their heads, and c.) since most combat takes place under 300 meters the extra range would be unnecessary. Is there any merit to this line of thinking? What cases can be made for using more powerful, longer ranged cartridges in SDMRs and (tripod or vehicle mounted) machine guns?
    • By Wiedzmin
      have question about 12.7x99 AP M2 cartridge  WWII time books gives muzzle velocity for AP M2 - 895 m/s for 45in barrel, modern days firing tables and manuals gives 856 m/s for 45in barrel, which is correct, or both correct but 1st for WWII and 2nd for modern dayes cartridges ?
×
×
  • Create New...