H.E. Shells striking armour and their effect

[ClintHardware]

Hi All

Post-war we know that High Explosive Squash Head (HESH) was designed to produce fragmentation and scabbing from the interior surface of armour.

Are there known examples of H.E. Shells achieving the same to a lesser degree? I know of one instance where a H.E. shell from a 25-Pdr appeared to cause an internal explosion within a Panzer III or IV in 1941/2 having been fired "Cap On" to protect the fuse to delay detonation by a nano-second or so at the point of impact.

[Michael Kenny]

There is a document out there on a test where Churchill tanks were driven through a live 25 pdr barrage to find out how effective HE fire was on buttoned up tanks. My memory says they did it twice as the first run was so innefective they doubled the rate of fire and did it again. Same result.

[amcl]

There is a document out there on a test where Churchill tanks were driven through a live 25 pdr barrage to find out how effective HE fire was on buttoned up tanks. My memory says they did it twice as the first run was so ineffective they doubled the rate of fire and did it again. Same result.

Wasn't it a Cold War-era NATO truism that 155mm fire was needed to have much effect on tanks? With forty-ton tanks & 25-pdr fire, the results appear to have been in line with later expectations. I think we are entitled to doubt whether driving through a medium artillery barrage would have been quite so uneventful. Here, for example, is what seems to be a case of a mission kill of a Tiger II hit by direct rather than plunging fire using a 25kg HE-fragmentation round.

Shot #1. Target: upper front plate. Shell: 122 mm HE-fragmentation.
Result: spalling across an area 300 mm by 300 mm. The welding seam between the upper front plate and the machine gun port burst on 3/4 of its circumference. Internal bolts holding the machine gun ball were torn off. The welding seam between the upper front plate and the right side burst, and the right side was displaced by 5 mm. The tank caught fire internally.

(Found at http://tankarchives.blogspot.co.uk/2013 ... -cats.html)

Cheers,

Angus

[StefanSiverud]

There is a document out there on a test where Churchill tanks were driven through a live 25 pdr barrage to find out how effective HE fire was on buttoned up tanks. My memory says they did it twice as the first run was so innefective they doubled the rate of fire and did it again. Same result.

If you can find said document, please share. It sounds strange that there was neither spalling nor damage to tracks and wheels if the barrage was laid on the tanks. Maybe if it was laid close to them and the test was intended to show the effect of shell fragments on tanks.

EDIT: No need to find the document, it was quite easy.

WO 291/399 Casualties to Churchill tanks in 25-pdr concentrations.
A trial conducted in 1943 tested proposed new tactics, whereby Churchills would advance though
concentrations of friendly 25-pdr fire, by twice driving a squadron of Churchills through live artillery
fire. It is concluded that the worst that can happen to a Churchill in these circumstances is
immobilisation. The effect of a 25-pdr round exploding on a Churchill is described thus:
"There is no adverse effect on the crew from a 25 pdr direct hit. Fragments cannot penetrate the tank,
and the blast is not at all uncomfortable."

Source: http://mr-home.staff.shef.ac.uk/hobbies/ww2eff2.pdf
Also referenced here: http://forum.axishistory.com/viewtopic. ... 30#p949053

So immobilisation was an issue at least. I still find it surprising spalling was not. But then again, I seem to recall the same thing was true at Dieppe, where none of the tank crews were wounded inside their tanks and the tanks were not penetrated until after the crews had left them towards the end of the battle, when the German AT-guns were moved closer.

[Michael Kenny]

Hit 86 is a HE splash.

[phylo_roadking]

Wasn't it a Cold War-era NATO truism that 155mm fire was needed to have much effect on tanks? With forty-ton tanks & 25-pdr fire, the results appear to have been in line with later expectations. I think we are entitled to doubt whether driving through a medium artillery barrage would have been quite so uneventful.

...or, of course, much lighter tanks - lighter in terms both of weight and thickness of upper hull and engine deck armour - in the early war period

So immobilisation was an issue at least. I still find it surprising spalling was not. But then again, I seem to recall the same thing was true at Dieppe, where none of the tank crews were wounded inside their tanks and the tanks were not penetrated until after the crews had left them towards the end of the battle, when the German AT-guns were moved closer.

The Churchill was opriginally spec'd (see the long british tank design thread) as a heavy assault tank, for crossing rough country - in other words, for breaking the expected trenches' stalemate and ultimately attacking the Siegfried Line in the general offensive of 1942...ahem! Which would naturally have been an artillery-rich environment...!

[Urmel]

There's an interesting discussion on this in the Neville Quilliam report of January 1942, looking at the experience in the desert. They surmised that the energy of the hit was still transferred into the tank, leading to e.g. items catching fire, and causing casualties, even if there was no penetration. My guess is the guns that dished out the punishment were of Gruppe Boettcher, and either 155mm GPF, 17cm K18, or 21cm Moerser 18.

[phylo_roadking]

WO 291/399 Casualties to Churchill tanks in 25-pdr concentrations.
A trial conducted in 1943 tested proposed new tactics, whereby Churchills would advance though
concentrations of friendly 25-pdr fire, by twice driving a squadron of Churchills through live artillery
fire.

I wonder which actually came first - the new tactics, pertaining to which somebody thankfully decided it might be a good idea to test if the tanks could take it....or the test?

I still find it surprising spalling was not.

IIRC spalling had a lot to do with both the thickness of the armour absorbing the force of impact and the (much more limited than an A/T round's) kinetic energy...and the quality of armourplate itself.

[Graeme Sydney]

If I was an inf comdr and I had Field arty In Range or In Support I would certainly be asking for it if attacked by tanks.

Field Arty would force them to fight 'closed up' reducing their efficiency and separate them from supporting infantry giving any inf a/tk weapons a better chance of a kill. Mix in some WP and you'll further confuse and break up the org, smoke up their lens and set alight loose equipment and aux fuel tanks on the outside of the tank. Near misses and air-bursting arty might also sever radio aerials and puncture aux fuel tanks - all good things for the defense but I wouldn't expect field arty 25pnd/105's to defeat a tank attack - but it would be in the mix.

Medium arty would be even more effective with the chance of very near misses overturning a tank.

But the problem with both is getting concentration of fire onto a fast moving target, and the slow rate of medium arty fire makes it even less effective. The only way arty fire could be expected to have a telling impact on a tank attack is by firing on per-registed targets such as assembly areas and FUP's or on identified likely approaches, choke points, defiles or obstacles, at just the right moment in high concentrations.

I wouldn't expect a direct hit plunging fire from field arty to immobilise a MBT of 1940 onwards. I can't see it hitting the tracks or road wheels. A direct, and very lucky, hit on the engine cover might reveal a weakness. I can see a direct hit throwing the crew around and maybe creating casualties in the cab, even deaths, reducing the efficiency of the tank/crew but not a 'tank kill'.

I have no evidence but I suspect a direct hit from plunging medium arty would a 'tank kill' on most medium MBT of 1940 onwards. I would doubt there would be penetration but I would suspect the HESH effect breaking away equipment and fittings on the inside of the tank and severely throwing around the crew causing death and injuries.

'Sir, if you want me to stop tanks please give me another tank'.

[Delta Tank]

Graeme,

I agree with everything that you posted above, in fact I do believe there are US Army doctrinal manuals that say basically the same thing. I don't know, but I would be surprised if a near miss by medium (155mm) arty round would flip a tank, not a lot of explosive in a round that small, they hold about 15 or so pounds of explosive, but I am not sure, but it may break the track.

Hitting a moving column or formation with artillery is tough, we practiced doing it a lot and it is hard! But, if you can get the formation into a constricted area (defile) and stopped by an obstacle. . .good things will happen!!

Good post!

Mike

[ClintHardware]

Here is are some post-Beda Fomm direct fire test firing of 25-Pdr A.P. Shot and H.E. and Boyes Anti-Tank Rifle against an M.13. There was no A.P. Shell issued for the 25-Pdr so I imagine that it must be A.P. Shot.

This is from WO 169/1240 and is from a joint CYRCOM and XIII Corps Intelligence Summary with information up to 2000 hrs 15th February:

Projectile Effect
(i) 25 Pdr at 800 yds A.P. Shell..........................Straight through both sides of tank
".......".......".... with instantaneous fuze........Made a large hole in one side of tank
".......".......".... with short delay fuze............Shell burst inside tank

(ii) Boyes A.Tk Rifle at 500 yds..........................Dented armour but did not penetrate


The short delay fuze may be exactly that instead of "Cap On" to achieve a delay. Its amazing that the H.E. did that amount of damage to armour. Of course they could not test for hardness and malleability in the field.

The 25-Pdr Churchill tests mentioned above in this topic were indirect fire.

[phylo_roadking]

Its amazing that the H.E. did that amount of damage to armour. Of course they could not test for hardness and malleability in the field.

Not necessarily; didn't Italian armour plate have an unenviable reputation for being brittle and cracking easily?

[ClintHardware]

A 1943 report by the Military College of Science, School of Tank Technology in Surrey, England, provides a different story. A detailed description was made of a captured working M.13 with the markings:

CARRO TIPO M.13 TARGA 3596 ANNO 1941
MATRICOLA No. 01473w

01473w was used for Poldi testing of the M.13’s various armour plates to establish their qualities. They were found to be of homogenous machineable quality armour with a moderate Brinell Hardness Number that could be expected to have enough malleability to avoid shatter. Perhaps the earlier problems of brittle armour in the M.11-39 and M.13 had been addressed in later production runs.

Preliminary Report No. 18 Italian Tank M 13/40, November 1943
“Examination by the “Poldi” portable hardness testing equipment indicates the armour to be of homogeneous machineable quality throughout varying from 210 Brinell in the case of the turret front to 245 Brinell in the case of the nose plate.”

The unique manufacturing identity number (Matricola) of 01473w seems to indicate that this was a later production M.13 so it might have been better armoured (some 700 plus were thought to have been manufactured) than those at Beda Fomm.

[phylo_roadking]

A 1943 report by the Military College of Science, School of Tank Technology in Surrey, England, provides a different story. A detailed description was made of a captured working M.13 with the markings:

CARRO TIPO M.13 TARGA 3596 ANNO 1941
MATRICOLA No. 01473w

01473w was used for Poldi testing of the M.13’s various armour plates to establish their qualities. They were found to be of homogenous machineable quality armour with a moderate Brinell Hardness Number that could be expected to have enough malleability to avoid shatter. Perhaps the earlier problems of brittle armour in the M.11-39 and M.13 had been addressed in later production runs.

Preliminary Report No. 18 Italian Tank M 13/40, November 1943
“Examination by the “Poldi” portable hardness testing equipment indicates the armour to be of homogeneous machineable quality throughout varying from 210 Brinell in the case of the turret front to 245 Brinell in the case of the nose plate.”

The unique manufacturing identity number (Matricola) of 01473w seems to indicate that this was a later production M.13 so it might have been better armoured (some 700 plus were thought to have been manufactured) than those at Beda Fomm.

Clint - not necessarily - look again...

CARRO TIPO M.13 TARGA 3596 ANNO 1941
MATRICOLA No. 01473w

01473w was used for Poldi testing of the M.13’s various armour plates to establish their qualities. They were found to be of homogenous machineable quality armour with a moderate Brinell Hardness Number that could be expected to have enough malleability to avoid shatter. Perhaps the earlier problems of brittle armour in the M.11-39 and M.13 had been addressed in later production runs.

Preliminary Report No. 18 Italian Tank M 13/40, November 1943
“Examination by the “Poldi” portable hardness testing equipment indicates the armour to be of homogeneous machineable quality throughout varying from 210 Brinell in the case of the turret front to 245 Brinell in the case of the nose plate.”

The unique manufacturing identity number (Matricola) of 01473w seems to indicate that this was a later production M.13 so it might have been better armoured (some 700 plus were thought to have been manufactured) than those at Beda Fomm.

Later Italian AFV production does seem to have been far better than what they began the war with; but the "unique properties" of early-war Italian armour was indeed perceived at Beda Fomm IIRC. The first highlighted statement does pretty much confirm that there were perceived"... earlier problems of brittle armour in the M.11-39 and M.13".

[ClintHardware]

I can't disagree - we have a lack of evidence and probably only guess work now and into the future unless we can find one in Libya being used as a garden shed and get permission to live fire a 25-Pdr.......I can't see this happening.

Here is a Matilda example from the 1st May 1941:

Lieutenant Alexander McGinlay, ‘D’ Squadron, 7th Royal Tank Regiment
- “we had received a direct hit from an enemy 105 mm gun at very short range. The whole of the thick armour all along the side of the tank had sprung open, about three or four inches. That shows how tough these Matildas were. All we noticed was a kick on the leg from a 2-Pdr shell dislodged from its rack and a puff of wind.” (WO 169/1417)

This reads like sprenggranat rather than panzergranat or hohlraumgranat. If he experienced a "puff of wind" it sounds like the hull side armour had been opened and not just the armour over the running gear. However, I have no other evidence to hand.