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Firing through the driver viewing slot

PETERPANs

FNG / Fresh Meat
Jul 10, 2009
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Anyone got any research besides guessing and assumptions?
Bulletproofing is the process of making something capable of stopping a bullet or similar high velocity projectiles e.g. shrapnel. The term bullet resistance is often preferred because few, if any, practical materials provide complete protection against all types of bullets, or multiple hits in the same location.
Bullet designs vary widely, not only according to the particular firearm used (e.g. a 9x19mm Parabellum caliber hollowpoint handgun cartridge will have inferior penetration power compared to a 7.62x39mm assault rifle cartridge), but also within individual cartridge designs. As a result, whilst so-called "bullet-proof" panels may successfully prevent penetration by standard 7.62x39mm bullets containing lead cores, the same panels may easily be defeated by 7.62 x 39 mm armor piercing bullets containing hardened steel penetrators.




For me its clear, it is not designed to stop anti - tank weapon like ammo. The PTRS projectile weighed 65.5 grams and was 51 millimeters long with a 38.7 gram core of tungsten carbide with 1.8 grams of incendiary material in the tip. The overall round weighed approximately 200 grams and was 155 millimeters long. The projectile has a muzzle velocity of approximately 1,000 meters per second and could penetrate 30 millimeters of steel at an incidence of 60 degrees at a range of 100 meters, or 25 millimeters at a range of 500 meters.
 

LemoN

FNG / Fresh Meat
Feb 26, 2006
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Bulletproofing is the process of making something capable of stopping a bullet or similar high velocity projectiles e.g. shrapnel. The term bullet resistance is often preferred because few, if any, practical materials provide complete protection against all types of bullets, or multiple hits in the same location.
Bullet designs vary widely, not only according to the particular firearm used (e.g. a 9x19mm Parabellum caliber hollowpoint handgun cartridge will have inferior penetration power compared to a 7.62x39mm assault rifle cartridge), but also within individual cartridge designs. As a result, whilst so-called "bullet-proof" panels may successfully prevent penetration by standard 7.62x39mm bullets containing lead cores, the same panels may easily be defeated by 7.62 x 39 mm armor piercing bullets containing hardened steel penetrators.




For me its clear, it is not designed to stop anti - tank weapon like ammo. The PTRS projectile weighed 65.5 grams and was 51 millimeters long with a 38.7 gram core of tungsten carbide with 1.8 grams of incendiary material in the tip. The overall round weighed approximately 200 grams and was 155 millimeters long. The projectile has a muzzle velocity of approximately 1,000 meters per second and could penetrate 30 millimeters of steel at an incidence of 60 degrees at a range of 100 meters, or 25 millimeters at a range of 500 meters.
Oh christ.

Do you have anything other than assumptions and wikipedia copy&paste? :rolleyes:

Thing is that the "bullet proof glass" was a 65mm glass block. Now we all know that glass is incredibly hard but also very brittle. But brittleness only is a problem against overmatching rounds, not against rounds that are vastly smaller than the armour itself. I'll play the devils advocate here and say that I don't believe the PTRD would penetrate/destroy a 65mm block of glass.

Shatter it's outside? Probably. Make it crack? Probably.
 
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PETERPANs

FNG / Fresh Meat
Jul 10, 2009
505
106
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Thing is that the "bullet proof glass" was a 65mm glass block. Now we all know that glass is incredibly hard but also very brittle. But brittleness only is a problem against overmatching rounds, not against rounds that are vastly smaller than the armour itself. I'll play the devils advocate here and say that I don't believe the PTRD would penetrate/destroy a 65mm block of glass.

Shatter it's outside? Probably. Make it crack? Probably.
things like sloped glass doesnt exist, in general its block of glass, and you hit it by 70-90 degrees (in general), it stop small bullets but not AT core ammo.

Again 14.5x114mm cartridge.
Ballistic performance Bullet weight/type Velocity Energy
59.6 g (920 gr) BZT API-T 1,000 m/s (3,300 ft/s) 29,800 J (22,000 ft
 
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LemoN

FNG / Fresh Meat
Feb 26, 2006
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Seriously, could you please stop assuming and guessing? Also, you don't have to post this load of copy&paste wikipedia data, I'm well aware of the potential energy of the PTRD and what it can actually do, see the PTRD thread in the general discussions section.

Oh well, since I probably can't stop you from wildly guessing and throwing around useless data I'll just post my thoughts on this matter here. :rolleyes:

The simple maths is this, any armour can "overmatch" incoming rounds, the more it overmatches the incoming projectile the less effect brittleness of the armour has and the more effective hardness becomes. Chances are high that a 300mmx70mmx65mm block of glass has higher resistance to an incoming PTRD round than an equal block of RHA armour. I'm pretty sure it would still crack, but not in any catastrophic way that would "blow out" the glass. It would probably take multiple hits to destroy it, giving the crew enough time to replace it easily. Of course the reverse applies to any round that's only marginally overmatched by the extremely brittle glass, like a 37mm round for instance.

Modern bullet proof glass simply utilises a method to make large areas of glass more resistant to large area deformations by, with a roughly 300mmx70mmx65mm block this isn't the case, since the block of glass we're talking about doesn't have the surface area to "bulge in" like a normal windscreen would. This and heat resistance are the only reasons modern bullet proof glasses have layers of plastic and polymer glue in it.

Another interesting thing are Soviet manuals on how to use the PTRD, it calls specifically for shooting the vision slit to scratch/shatter the outside of the glass and reduce the vision of the tank, nowhere have I ever read that they should aim there to kill the driver.

Doesn't anybody have actual studies on this subject?
 
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Capt.Cool

FNG / Fresh Meat
Jan 5, 2010
777
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Sky high
I don't believe the PTRD would penetrate/destroy a 65mm block of glass.

Shatter it's outside? Probably. Make it crack? Probably.
leaving all assumptions and theoretical math beside its clear bulletproof glass will be shattered by Ptrd and Mg hits.



the person behind the glass will be still save, but his vision will be reduced.


Another interesting thing are Soviet manuals on how to use the PTRD, it calls specifically for shooting the vision slit to scratch/shatter the outside of the glass and reduce the vision of the tank, nowhere have I ever read that they should aim there to kill the driver.

Doesn't anybody have actual studies on this subject?
No studies, but on youtube you can find the german WW2 instruction movie (thanx to Crni-Wuk for finding this) YouTube - WW2 PANTHER TANK VS SOVIET INFANTRY

At 2:30 there is the case of a soviet Mg shooting at the commanders cuppola glasses just to reduce his vision.
So you can assume that this happened many times and was a standard procedure of the soviets.
 
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LemoN

FNG / Fresh Meat
Feb 26, 2006
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I never doubted that. :)

It's pretty clear that nearly all hits with rifle/mg rounds (most likely even pistol rounds) would shatter/crack the glass and reduce the vision. The question at hand is if the PTRD and similar weapons could actually penetrate and destroy the armoured glass of a Pz. IV G.
 
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NoxNoctum

FNG / Fresh Meat
Jun 15, 2007
2,971
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Yes, that one.
And did really all tanks have those?
I remember my grandfather telling me how they had those disk-like grenades that they would put through the vision slot on the T34.

That was on the T34, mind you.
Or maybe even KV's, I don't remember.
What was your grandfather's "MOS" and what division was he in?
 

Crni-Wuk

FNG / Fresh Meat
Oct 16, 2010
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there is the case of a soviet Mg shooting at the commanders cuppola glasses just to reduce his vision.
So you can assume that this happened many times and was a standard procedure of the soviets.
No clue how accurate it is though but they mention infantry regularily using machineguns trying to destroy or damage the optical equipment of tanks.

YouTube - WW2 PANTHER TANK VS SOVIET INFANTRY
 

PETERPANs

FNG / Fresh Meat
Jul 10, 2009
505
106
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BOYS YOU MIGHT WANT TO CHECK THIS OUT.

Glass (5-10mm) provides "Bullet proof" protection against SVD Druganov sniper rifle.


Sturm
2008 - 1942 = 66 years

Do not tell me that glass from 2008 is same, have same technology inside, have same quality, have same structure and used materials :rolleyes:

Also SVD is 7,62 calibre, its not 14,5 or 12,7 calibre. SVD is antisoldier weapon, its not designed to fight armored things as main target, yes there is anti-armor ammo but thats all its still 7,62 mm. While PTRD is designed only for penetration, have longer barrel, so your example is obsolete.
 
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LemoN

FNG / Fresh Meat
Feb 26, 2006
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This isn't bullet proof glass, it's simply normal safety glass (the same stuff you have on your car's windshield) stacked together. The problem with that is that once the first layer of glass is destroyed the shockwave will simply blow out the following ones.

You don't have that problem with one single block of glass, that can't bulge in.

I asked Alan (Wilsonam) on this matter and he told me that the glass in a pz. IV has the resistance of roughly 150BHN RHA armour, ie it's like shooting a 65mm block of 150BHN (soft) steel in terms of overall resistance it puts up before failing. I can't confirm it so please don't take this as granted, as Alan also wasn't 100% sure about it.
 
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PETERPANs

FNG / Fresh Meat
Jul 10, 2009
505
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This isn't bullet proof glass, it's simply normal safety glass (the same stuff you have on your car's windshield) stacked together. The problem with that is that once the first layer of glass is destroyed the shockwave will simply blow out the following ones.

You don't have that problem with one single block of glass, that can't bulge in.

I asked Alan (Wilsonam) on this matter and he told me that the glass in a pz. IV has the resistance of roughly 150BHN RHA armour, ie it's like shooting a 65mm block of 150BHN (soft) steel in terms of overall resistance it puts up before failing. I can't confirm it so please don't take this as granted, as Alan also wasn't 100% sure about it.
If it is 150BHN its not enough, in general WWII era armor steel have 250 BH, plus minus. PTRD (tungsten ammo) is able to penetrate 40 mm (250 BHN material) from 100 metres at 90 degrees. 150 BHN is 40-45 percent less stronger than WWII armor steel. Tungsten carbide have 1200-1500 BHN, so imagine results vs 60 mm 150 BHN material.

The bulletproof glass of World War II was much heavier that made today. The bulletproof laminate was made by gluing sheets of glass together with liquid rubber. ITS NOT SOLID GLASS BECAUSE ---------> In the bullet proof glass, the Laminate-layers of tough plastic called polycarbonate sandwiched in between the pieces of thoughened glass make the glass ten times thicker than the ordinary glass and it is very heavy. If someone fires a bullet at an ordinary piece of glass, the glass can^t bend and absorb the energy. So the glass shatters and the bullet carries on through with hardly any loss of momentum. That^s why ordinary glass offers no protection against bullets.


NOTE, LONG BEFORE WWII ...
Laminated glass was discovered on accident by a French chemist in 1903. Edouard Benedictus came across the invention through carelessness in the laboratory when he dropped a glass beaker, which had been coated with a plastic cellulose nitrate, on the floor. The beaker broke into pieces but did not come apart. He realized that this was due to the viscous collodion that lined the inside of the beaker. This gave way to the development of a glass-plastic composite for use in automobiles. Although it was not immediately adopted by the automobile industry it found widespread use in the military as eyepieces for gas masks during World War I.
 
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Colt .45 killer

FNG / Fresh Meat
May 19, 2006
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Why are people downvoting lemon? If you have counter arguments be a man and post them instead of hiding behind a damned minus button.

I'm going to have to agree with lemon on this. The russians regularly performed tests on captured tanks and made good of those tests. If they had discovered that their AT rifles could penetrate the armoured glass in the drivers view slot they would have instructed their AT Riflemen to try and shoot their to kill the driver, not scratch/damage his viewing glass.
 
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Mormegil

FNG / Fresh Meat
Nov 21, 2005
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Nargothrond
I have a question. Was the glass prism type, like an SLR camera's penta prism? this would mean if a round could penetrate the glass, it would hit steel on the other end, and not get into the cabin.

It's the whole periscope like thing mentioned earlier, but without being as complicated.
 

LemoN

FNG / Fresh Meat
Feb 26, 2006
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I have a question. Was the glass prism type, like an SLR camera's penta prism? this would mean if a round could penetrate the glass, it would hit steel on the other end, and not get into the cabin.

It's the whole periscope like thing mentioned earlier, but without being as complicated.
AFAIK only on later tanks, the Pz4 and similar German tanks had normal glass.