Balistic: rifle vs armoured car

[bonzillou]

Hello

Bonjour
I'd like to know if the standard WW1 rifle (Lebel, lee-Enfield, Gewehr 98, Mosin Nagant, etc...) using its standard bullet could do any harm to armoured cars (with armoured plate being usually between 3 and 6mm except for the Rolls-Royce Armoured Car which had a 12mm armoured plates!)
Thanks
Pascal

[JMB1943]

Pascal,

 

The maximum penetration of the SMLE 303 round at 30 yds at right angles to a plate is

7/16 inch = 11 mm for steel plate (best hard),

and 0.75 inch = 19 mm for ordinary mild or wrought iron.

 

3/16 inch = 4.8 mm is proof at 600 yds.

If the plate is set at a slope of 3/2, then 4.8 mm is proof at 250 yds.

 

Data from (British Army) Field Service Pocket Book, 1914, General Staff, War Office, p. 90.

 

I imagine that other service rifles would give similar results, depending on the muzzle velocity and hardness of the round.

 

Regards,

JMB

[bonzillou]

Thanks a lot JMB.

This means that a lucky rifle shot could penetrate an armoured car armoured plate.

Interestingly, if we talk about tanks, as the Mark I has some of its armour no more than 6mm thick, it could also have been a rifle target.

 

Thanks too for reminding me about  the British Army Field Service Pocket Book, 1914, General Staff, War Office

which can be found at:

https://archive.org/details/b28998558/page/108/mode/2up

 

Cheers

Pascal

[JMB1943]

Pascal,

 

I have an old printed copy and was not aware of the on-line link.

 

Amicalement,

JMB

[bonzillou]

Lucky you!

[Gareth Davies]

13 hours ago, JMB1943 said:

 

3/16 inch = 4.8 mm is proof at 600 yds.

If the plate is set at a slope of 3/2, then 4.8 mm is proof at 250 yds.

 

 

 

And that, dear chums, is why we slope the armour on the front of our tanks.

[MKC]

Not only does the slope help to deflect the projectile, but it also increases the depth of armour to be penetrated. A 4.8 mm plate sloped a 3H:2V results in a depth of armour to be penetrated of 7.2 mm if my elementary grasp of maths is correct. The Russians in WW2 had it right with the design of the T34. 

 

Mike

[The Scorer]

Wasn't there a problem with the early tanks with bullets penetrating the sides and richohsheting (sorry about the spelling!) around the inside of the body?

[Keith Woodland]

I'm sure I have seen in Bovington Tank Museum a large rifle of German origin especially designed for use against tanks in WW1.

By the WW2 there was the Boyes anti tank rifle and I also recall being told an SLR 7.62 MM would penetrate the rear doors of a Saracen APC.

[Gunner Hall]

On 09/03/2020 at 20:51, The Scorer said:

Wasn't there a problem with the early tanks with bullets penetrating the sides and richohsheting (sorry about the spelling!) around the inside of the body?

I seem to remember that the  main problem was "spalling" a bullet wouldn't necessarily have to penetrate the plate, as the reverse of the plate would break off in tiny fast moving fragments This from wikipedia " creating a shock wave that travels through the armor as a compression wave and is reflected at the free surface as a tensile wave breaking (tensile stress/strain fracture) the metal on the inside."  The crews were often supplied with chainmail masks  to protect against this,  The same effect, though much later - and larger was the modus operendi of the HESH round.  

On 10/03/2020 at 12:50, Keith Woodland said:

I'm sure I have seen in Bovington Tank Museum a large rifle of German origin especially designed for use against tanks in WW1.

By the WW2 there was the Boyes anti tank rifle and I also recall being told an SLR 7.62 MM would penetrate the rear doors of a Saracen APC.

This is out of scope of the GW, and I apologise in advance.  Thankfully, we didn't often have to face the prospect of a 7.62 NATO  FMJ coming through the doors.  Much worse was the effect of a ND from a SMG, or Federal Riot Gun, when the bus was closed up.  How we laughed....

Edited 11 March , 2020 by Gunner Hall

[Open Bolt]

1 hour ago, Gunner Hall said:

Much worse was the effect of a ND from a SMG, or Federal Riot Gun, when the bus was closed up

Gods! How many bounces would they make before they found something?

[Gunner Hall]

Too many.  If you were lucky the baton round would snag under a seat early in it's progress around the compartment.  The early marks of "Fed" were notorious for going off if you as much as looked at them. To be fair, it didn't often happen as the correct procedure was to keep the thing broken and unloaded.  

[Open Bolt]

Frightening / interesting...

[QUEX]

On 10/03/2020 at 12:50, Keith Woodland said:

I'm sure I have seen in Bovington Tank Museum a large rifle of German origin especially designed for use against tanks in WW1.

 

This?  https://www.youtube.com/watch?v=ko9A3ZbN8ZU

 

I think there used to one hanging on a wall at Bisley

[Keith Woodland]

2 hours ago, QUEX said:

This?  https://www.youtube.com/watch?v=ko9A3ZbN8ZU

 

I think there used to one hanging on a wall at Bisley

That's looks like the one I remember in Bovington Museum.

[bonzillou]

Hello

i'm aware of the Tankgewehr.

My question was about the standard WW1 rifle (Lebel, lee-Enfield, Gewehr 98, Mosin Nagant, etc...) using its standard bullet.

 

JMB gave me an answer with a pretty good source.

The funny thing is that I reported these elements on the french forums and some people said that "

The maximum penetration of the SMLE 303 round at 30 yds at right angles to a plate is

7/16 inch = 11 mm for steel plate (best hard)" is impossible.

 

[The Scorer]

On 11/03/2020 at 13:10, Gunner Hall said:

I seem to remember that the  main problem was "spalling" a bullet wouldn't necessarily have to penetrate the plate, as the reverse of the plate would break off in tiny fast moving fragments This from wikipedia " creating a shock wave that travels through the armor as a compression wave and is reflected at the free surface as a tensile wave breaking (tensile stress/strain fracture) the metal on the inside."  The crews were often supplied with chainmail masks  to protect against this,  The same effect, though much later - and larger was the modus operendi of the HESH round.  

 

Thanks - I remember that now!

[david murdoch]

Interesting reading. I've seen quite a bit relating to this in the War Diaries of 8th and 9th L.A.B s who were still operating in France in 1917 (with Rolls Royce). There is a lot of detail - basically a step by step over the months as they tried out additional armour due to danger from armoured piercing bullets and regular fire. This highlights them adding additional armour (gun jackets, gun shields and fuel tanks in particular) the units themselves coming up with designs and ideas. Then also mentioned the addition of Uralite sheet cladding. There is an entry discussing proof trials made (at Calais) where the test car was holed by regular bullets as well as armoured piercing and then satisfactory tests against regular and armour piercing rounds with one layer of cladding, but it seems they fitted two layers to be on the safe side! In addition you can see there was a preoccupation with the additional weight of these additions and some ideas were rejected due to this (interestingly add on weights noted in kgs). At the same time they were having more issues with wheels, springs, broken axles ect and were at  the limits of what the chassis could support. They were proposing to fit a truck rear axle to stand the greater weight. By this time there were only 16 Rolls operating in France and most of them ended up shipping out to Mesopotamia at the end of 1917 and early 1918.

Those cars shown in photos at Arras also appear later in Mesopotamia and it's clear pretty all these armour modifications (apart from turret extensions) were removed presumably due to requirement to be lighter and more mobile and facing less heavy fire. It is noted in one of the War Diaries from there them coming under fire and damage being done by Turkish armoured piercing rounds.

 

The note below is from the L.A.M.B training manual from Mesopotamia in 1918.

 

Protection against Rifle Fire.

 

4. The plating of light armoured cars is proof against bullets (excluding armour piercing bullets), shrapnel, and splinters from shell, but is not proof against a direct hit from any calibre of gun, or against armour piercing bullets. Under rifle fire, their only vulnerable points are the tyres;

Page 16.

 

the fly-wheel and under parts of the engine are also liable to be damaged by bullets which ricochet off the ground. It is therefore possible for armoured cars to approach enemy trenches held by rifle-men or machine guns, with comparative impunity, provided that the ground is hard and sound, and allows the cars to move quickly.

 

Edited 21 March , 2020 by david murdoch

[david murdoch]

On 11/03/2020 at 10:10, Gunner Hall said:

I seem to remember that the  main problem was "spalling" a bullet wouldn't necessarily have to penetrate the plate, as the reverse of the plate would break off in tiny fast moving fragments This from wikipedia " creating a shock wave that travels through the armor as a compression wave and is reflected at the free surface as a tensile wave breaking (tensile stress/strain fracture) the metal on the inside."  The crews were often supplied with chainmail masks  to protect against this,  The same effect, though much later - and larger was the modus operendi of the HESH round.  

This is out of scope of the GW, and I apologise in advance.  Thankfully, we didn't often have to face the prospect of a 7.62 NATO  FMJ coming through the doors.  Much worse was the effect of a ND from a SMG, or Federal Riot Gun, when the bus was closed up.  How we laughed....

Interesting test to prove the reversed round story.

https://owlcation.com/humanities/About-World-War-1-German-Bullets-vs-Allied-Tanks

[bonzillou]

Excellent sources David, thanks a lot, this is exactly what I was looking for.

[MikB]

I can remember reading that one type of armoured car (maybe Crossley?) was protected by "Beardmore's Special Bulletproof Plate 3/16 thick". Even as a teenager I'd already seen 303s embedded in steel plates a good deal thicker than that, though the stuff looked too ductile to be anything more than mild steel.

 

To be effective protection at close battle ranges it would indeed have to be pretty 'Special'.

[david murdoch]

William Beardmore and Co. in Glasgow were one of the main suppliers of armour plate due to them already being set up as a major supplier of armour plate for Clyde built warships. From 1895 they had a 12,000 ton press to make American Harveyized armour plate and a lot of experience in the development of case hardened plate. Also due to the original Rolls Royce armoured cars  being produced for the RNAS. Admiralty pattern turrets for the armoured cars were produced there. 

[JMB1943]

On 11/03/2020 at 17:04, bonzillou said:

JMB gave me an answer with a pretty good source.

The funny thing is that I reported these elements on the french forums and some people said that "

The maximum penetration of the SMLE 303 round at 30 yds at right angles to a plate is

7/16 inch = 11 mm for steel plate (best hard)" is impossible.

 

Pascal,

 

You should challenge the "impossible" claim.

Have your French colleagues run the test with a (modern) steel plate and failed to achieve penetration?

I tend to believe the official War Office information in this case.

 

Regards,

JMB

[JMB1943]

On 19/03/2020 at 15:05, david murdoch said:

Protection against Rifle Fire.

 

4. The plating of light armoured cars is proof against bullets (excluding armour piercing bullets), shrapnel, and splinters from shell, but is not proof against a direct hit from any calibre of gun, or against armour piercing bullets. Under rifle fire, their only vulnerable points are the tyres;

Page 16.

 

 

 

 

David,

 

Is the thickness of this light plating known, as a comparison with what is claimed for the SMLE 0.303?

 

Regards,

JMB

[david murdoch]

Rolls Royce armour was 12mm /0.47". I took another look at the war diaries, showing they were constantly working on armour modifications  from early 1916 - almost as soon as the cars went to France with the MGC(M). The constant balancing of additional armour against weight and practicality is evident. Going by the diary (8th L.A.B) the uralite was only fitted a week or so before Arras - after being approved from the ballistic tests  -  the cars then being rotated into depot for modifications. They had also been camouflage painted prior to this but the photos from Arras are fresh painted over the new cladding. The photo attached clearly shows the thickness of this on and at the sides of the  open drivers panel comparing to an unmodified one.The top of the bonnets do not have cladding and the gun shield looks like it would be standard plate - those were also fitted in France an may have been cut from regular steel plate rather than actual armoured plate.