Russian Small Arms Against AFVs in 1941

[jacobs_ladder2]

Anyone know where I can get some decent numbers to nail down the effectiveness of infantry weapons against AFVs?

I'm looking mostly at the 7.62mm DT and DP LMGs, the Maxim MMG and the DShK HMG, but I have most likely missed something.

If you're wondering why, I'm trying to nail down the causes of German tank losses in 1941. Hint hint.

Help.

Paul

[jacobs_ladder2]

I do have data for German small arms which I believe to be credible. How do Russian small arms stack up against their counterparts?

Cheers

Paul

[Sergei]

Uhm, you wouldn't call AFV's Armoured if they wouldn't withstand small arms fire...

[jacobs_ladder2]

Originally posted by Sergei:

Uhm, you wouldn't call AFV's Armoured if they wouldn't withstand small arms fire...

From what I can tell they do withstand small arms fire...to a point. My question is, where is that point?

Cheers

Paul

[Bone_Vulture]

Originally posted by jacobs_ladder2:

From what I can tell they do withstand small arms fire...to a point. My question is, where is that point?

From tests the Soviet Maxim MMG penetrates 8@35 at 30m.

From tests the Soviet 12.7mm DShK HMG penetrates 8@35 at 800m and 30@0 at 25m.

That's the info I got from Chris Hare's penetration charts.

[MikeyD]

From what I've read the BTs had great trouble with small arms penetrations (German propaganda?), and most vehicles with the 8mm armor (U.S. halftracks for instance) were a deathtrap when they got a couple hundred meters from the front. About the same line was used for the BT in Spain and the halftrack in Africa. That the larger caliber shells would simply go in one side and out the other, but the small arms bullets would penetrate and rattle around on the inside. I heard of .50 cal Quad halftracks removing the gunner's shield for that reason - so the incoming bullet would just make one hole in the gunner instead of rattling around and chewing him up!

[Wartgamer]

Bullets can destroy the armored glass vision devices, sights, rubber on road wheels, antenna.

Ive fired bullets at steel plates (copper jacketed vs steel) and they seem to be very susceptiple to the angle. Slope would seem to dfeat them much easier than a solid steel penetrator. I would guess this is because the point of the bullet deforms (blunts) and the round is rapidly trying to force a larger portion of steel out of the way. Many of the bullets yaw when faced with multiple plates. That is, they penetrate one plate 'clean' but attack the next plate flying sideways and left a large 'key-shaped' dent. I did this to test spaced armor. A rifle bullet that can penetrate two steel plates back to back had problems with the same two plates seperated by a air gap. The air gap was fixed in one test (spacer with clamps) and in another test, the distance was set by using foam blocks. The foam block spacer method showed the best protection. I theorize that the penetrator lost momentum as it not only lost velocity from penetrating the first plate. It loses momentum because the first plate would have actually 'moved' as the foam gave way.

Any spaced armor that had 'flexible' mounts would show these same tendancies.

[flamingknives]

The foam would absorb energy from the impact, rather than just the plate absorbing momentum. The more massive the plate is, the less likely you are to see that effect. You ought to get the same effect with a large, thin, plate bowing under the impact.

Comparing German and Soviet bullets, I know that the Germans issued 'k' ammunition that was armour piercing and this was used extensively from their machine guns. I may be wrong, but I don't think that the Red Army issued 7.62 AP rounds on any large scale. As such, I would expect a slightly better showing from German SAA.

[jacobs_ladder2]

Originally posted by Bone_Vulture:

</font><blockquote>quote:</font><hr />Originally posted by jacobs_ladder2:

From what I can tell they do withstand small arms fire...to a point. My question is, where is that point?

From tests the Soviet Maxim MMG penetrates 8@35 at 30m.

From tests the Soviet 12.7mm DShK HMG penetrates 8@35 at 800m and 30@0 at 25m.

That's the info I got from Chris Hare's penetration charts. </font>

[jacobs_ladder2]

Originally posted by Wartgamer:

Bullets can destroy the armored glass vision devices, sights, rubber on road wheels, antenna.

Ive fired bullets at steel plates (copper jacketed vs steel) and they seem to be very susceptiple to the angle. Slope would seem to dfeat them much easier than a solid steel penetrator. I would guess this is because the point of the bullet deforms (blunts) and the round is rapidly trying to force a larger portion of steel out of the way. Many of the bullets yaw when faced with multiple plates. That is, they penetrate one plate 'clean' but attack the next plate flying sideways and left a large 'key-shaped' dent. I did this to test spaced armor. A rifle bullet that can penetrate two steel plates back to back had problems with the same two plates seperated by a air gap. The air gap was fixed in one test (spacer with clamps) and in another test, the distance was set by using foam blocks. The foam block spacer method showed the best protection. I theorize that the penetrator lost momentum as it not only lost velocity from penetrating the first plate. It loses momentum because the first plate would have actually 'moved' as the foam gave way.

Any spaced armor that had 'flexible' mounts would show these same tendancies.

Interesting. Would a smaller round be more susceptible to deflection due to it's smaller weight? In other words, a larger shell (say 37mm or 45mm) simply will not bounce off as easily? Am I right in assuming this?

Cheers

Paul

[jacobs_ladder2]

Originally posted by flamingknives:

The foam would absorb energy from the impact, rather than just the plate absorbing momentum. The more massive the plate is, the less likely you are to see that effect. You ought to get the same effect with a large, thin, plate bowing under the impact.

Comparing German and Soviet bullets, I know that the Germans issued 'k' ammunition that was armour piercing and this was used extensively from their machine guns. I may be wrong, but I don't think that the Red Army issued 7.62 AP rounds on any large scale. As such, I would expect a slightly better showing from German SAA.

Actually I'm glad you brought this up in this thread. In a separate thread I posted a link to this. The table mentions several different types of ammo for German small arms (or at least that is my undertanding of it). Unfortunately, I have never seen any of these abbreviations and am hard pressed to find a source of information explaining them to me.

Cheers

Paul

[Bone_Vulture]

Originally posted by jacobs_ladder2:

Interesting. Would a smaller round be more susceptible to deflection due to it's smaller weight? In other words, a larger shell (say 37mm or 45mm) simply will not bounce off as easily? Am I right in assuming this?

Although physics isn't my cup of tea, I'dsay there are two factors: impact energy divided by impact area, and both the armor's and the round's hardness. The impact energy is a combination of the round's velocity and mass. The smaller the impact area, the more focused this energy is, but as the shell's diameter in comparison to its impact energy becomes smaller, there's a higher risk that the round will simply shatter on impact. This is the hardness factor.

Finally there's the question of impact angle, but I'll leave that to the tank grogs.

[Wartgamer]

Originally posted by flamingknives:

The foam would absorb energy from the impact, rather than just the plate absorbing momentum. The more massive the plate is, the less likely you are to see that effect. You ought to get the same effect with a large, thin, plate bowing under the impact.

The plates just had foam blocks at the ends to act as standoffs. The bullet still went through an air gap and no foam. The projectile loses velocity from:

1. Penetrating the plate. The 1/2mv^2 component. The penetrator scrubs velocity as it goes through the plate.

2. From Momentum transfer. MV=mv. I know the plate moved btw. I used a tell tale device.

In a rigidly mounted armor system, like a panther hull, everything is more or less fixed. In some spaced armor applications, the attachments are not nearly as fixed. The Panzer III and Panzer IVs with armor packages are examples.

Bullets are generally much 'softer' than typical AP antitank rounds. Ive fired bullets at glass windshields at sharp angles and they can ricochet.

[flamingknives]

Sorry, didn't make myself clear. I was aware that the foam wasn't an intermediate layer.

I prefer to work in energy as it's easier to convert.

So: the bullet hits the plate, and transfers a proportion of its kinetic energy to the plate, which, as a consequence, starts moving. This energy has to go somewhere, otherwise the front plate will hit the rear one. It is transferred to the foam, which absorbs the energy by means of deformation (force times distance equals energy). A flexible plate fixed at the edges would also absorb energy from the projectile in the same way. The point is that flexibly mounted plates only work so far. Hit it hard enough and you'll crush the supports completely (plastic deformation)

[Wartgamer]

And it would be best if the outer plate was actually not face hardened but rather 'gave' with the penetrator. The plate has a much larger mass than the round. Having the round actually 'move' the whole assembly forces it to lose energy. It is not just deforming the bracket, it is fighting momentum.

I also theorize that the penetrator upun passing through the first plate rapidly loses its angular momentum. This 'spin-scrub' yaws the projectile after it passes through. I used a piece of paper to confirm that it was indeed yawing. That is, before striking the next plate.

I am surprised no one came up with the idea of a 'shopping-cart' type of armor. Basically it would be nothing more than a 'trailer' that would attach to the front of the tank. It could have steel wheels like a shopping cart (not steered just conform to direction of travel). The cart would have armor that is sloped sort of like an arrow shape (like the front of a JSIII).

When not used as armor, it could be trailed behind the tank for road marches (wheels get locked) and could be used to carry fuel. When used as armor, water is substituted into the tanks instead of fuel. This would further destabilize penetrators.

It might also act as a mine-detonator.

[jacobs_ladder2]

Originally posted by Bone_Vulture:

That's the info I got from Chris Hare's penetration charts.

What charts are you referring to here and where can I get them? They sound like a great source.

Cheers

Paul

[Andreas]

Originally posted by flamingknives:

I know that the Germans issued 'k' ammunition that was armour piercing and this was used extensively from their machine guns.

S.m.K. Spitzgeschoss mit Kern armor piercing (AP)

S.m.K.H. Spitzgeschoss mit Kern Hart AP w/tungsten carbide core

Pointed round with core

[flamingknives]

Originally posted by Wartgamer:

And it would be best if the outer plate was actually not face hardened but rather 'gave' with the penetrator. The plate has a much larger mass than the round. Having the round actually 'move' the whole assembly forces it to lose energy. It is not just deforming the bracket, it is fighting momentum.

I also theorize that the penetrator upun passing through the first plate rapidly loses its angular momentum. This 'spin-scrub' yaws the projectile after it passes through. I used a piece of paper to confirm that it was indeed yawing. That is, before striking the next plate.

I am surprised no one came up with the idea of a 'shopping-cart' type of armor. Basically it would be nothing more than a 'trailer' that would attach to the front of the tank. It could have steel wheels like a shopping cart (not steered just conform to direction of travel). The cart would have armor that is sloped sort of like an arrow shape (like the front of a JSIII).

When not used as armor, it could be trailed behind the tank for road marches (wheels get locked) and could be used to carry fuel. When used as armor, water is substituted into the tanks instead of fuel. This would further destabilize penetrators.

It might also act as a mine-detonator.

Depending on the thickness, of course, but face hardend ought to be uniformly better against soft bullets. Rather than letting the round through and taking some of its energy, you can force the projectile to use up all its energy in deforming/destroying itself.

As for the movement of the plate, if it (the plate) is moving as a rigid body, then all the energy is absorbed by the mounts. There's nowhere else for it to go. If the plate deforms, then that will absorb energy too. As far as the projectile/armour event is concerned, the interaction with the plate is just KE being transferred from the projectile to the plate. I'm just going one step further along the line.

As for the 'shopping cart', have you ever tried to push a shopping cart across a field? Now fill it full of water (1/8th of a ton, conservative estimate) and push across the field. Then try pushing across a ploughed field in the rain. It's just not going to work. Spaced armour, including some specifically designed to induce yawing in a projectile, were deployed in WWII and are still in use today.

[yuvuphys]

Don't forget, you're going to lose lots of energy to heat in the projectile and the armor plates. Most of the energy of the bullet is dissipated into heat, and the related deformation of both the bullet and the plate (i.e. the hole/crater from the bullet).

If the bullet hits at an angle to the plate, less momentum is impinging upon the plate, and the bullet's penetrating power will be relatively less, possibly to the point of not being able to force the metal plate past the elastic limit and allowing penetration.

[jacobs_ladder2]

Originally posted by Andreas:

</font><blockquote>quote:</font><hr />Originally posted by flamingknives:

I know that the Germans issued 'k' ammunition that was armour piercing and this was used extensively from their machine guns.

S.m.K. Spitzgeschoss mit Kern armor piercing (AP)

S.m.K.H. Spitzgeschoss mit Kern Hart AP w/tungsten carbide core

Pointed round with core </font>

[Bone_Vulture]

Originally posted by jacobs_ladder2:

What charts are you referring to here and where can I get them? They sound like a great source.

Doesn't anyone use Google anymore?

Here.

[flamingknives]

Originally posted by yuvuphys:

Don't forget, you're going to lose lots of energy to heat in the projectile and the armor plates. Most of the energy of the bullet is dissipated into heat, and the related deformation of both the bullet and the plate (i.e. the hole/crater from the bullet).

If the bullet hits at an angle to the plate, less momentum is impinging upon the plate, and the bullet's penetrating power will be relatively less, possibly to the point of not being able to force the metal plate past the elastic limit and allowing penetration.

Actually, if a bullet is hitting at an angle, it's facing a geometrically thicker target and the path of least resistance tends more to bouncing off the greater the angle is.

More energy will be lost to material deformation than to heat. Scaling up somewhat, a 17lb shell carries about 3MJ of energy. Only a small amount will be converted to heat. A 50g bullet will carry 20kJ. If a significant proportion converts to heat, you won't be needing incendiary bullets.

[Andreas]

Originally posted by jacobs_ladder2:

</font><blockquote>quote:</font><hr />Originally posted by Andreas:

</font><blockquote>quote:</font><hr />Originally posted by flamingknives:

I know that the Germans issued 'k' ammunition that was armour piercing and this was used extensively from their machine guns.

S.m.K. Spitzgeschoss mit Kern armor piercing (AP)

S.m.K.H. Spitzgeschoss mit Kern Hart AP w/tungsten carbide core

Pointed round with core </font>

[jacobs_ladder2]

Originally posted by Andreas:

</font><blockquote>quote:</font><hr />Originally posted by jacobs_ladder2:

</font><blockquote>quote:</font><hr />Originally posted by Andreas:

</font><blockquote>quote:</font><hr />Originally posted by flamingknives:

I know that the Germans issued 'k' ammunition that was armour piercing and this was used extensively from their machine guns.

S.m.K. Spitzgeschoss mit Kern armor piercing (AP)

S.m.K.H. Spitzgeschoss mit Kern Hart AP w/tungsten carbide core

Pointed round with core </font>

[jacobs_ladder2]

Originally posted by Bone_Vulture:

</font><blockquote>quote:</font><hr />Originally posted by jacobs_ladder2:

What charts are you referring to here and where can I get them? They sound like a great source.

Doesn't anyone use Google anymore?

Here. </font>