Not Re-2 pounder H.E again

[Don Juan]

OK, doing my own research, from Wikipedia, this is the SmK:

The K bullet is a 7.92×57mm (8×57mm IS) armor-piercing bullet with a tool steel core designed to be fired from a standard Mauser rifle. It was used by the German infantry against the first British tanks in World War I and on the Panzerkampfwagen I. On average the K bullet has a one out of three chance to penetrate armor 12–13 mm thick at a range of up to 100 meters.

And this is the Besa AP:

Hard steel core, lead-antimony sleeve, steel envelope

So from Wiki, the SmK could achieve 12-13mm penetration (I assume at normal) 33% of the time at 100m, so for the 8mm gun shield of the Pak 38, I'll invite everyone to speculate.

I would guess that the "hard steel core" of Besa AP, and the "tool steel core" of the SmK were analogous.

[Sheldrake]

OK, doing my own research, from Wikipedia, this is the SmK:

The K bullet is a 7.92×57mm (8×57mm IS) armor-piercing bullet with a tool steel core designed to be fired from a standard Mauser rifle. It was used by the German infantry against the first British tanks in World War I and on the Panzerkampfwagen I. On average the K bullet has a one out of three chance to penetrate armor 12–13 mm thick at a range of up to 100 meters.

And this is the Besa AP:

Hard steel core, lead-antimony sleeve, steel envelope

So from Wiki, the SmK could achieve 12-13mm penetration (I assume at normal) 33% of the time at 100m, so for the 8mm gun shield of the Pak 38, I'll invite everyone to speculate.

I would guess that the "hard steel core" of Besa AP, and the "tool steel core" of the SmK were analogous.

I am not sure about the origins of this story, or the effectiveness of 7.62mm AP rounds. IIRC the Germans had already issued an AP round to troops in 1916, not because they anticipated tanks, but to penetrate the armoured shields used to protect snipers and sentries. They did notm work against the Mk 1 tank. Now AP rounds could penetrate the Mk 2 tank, but the reason was because the mk 2 was built as a training vehicle and was built of un hardened steel. It was only used in Spring 1917 in desperation after the success of tanks on the Somme The mk IV was better armoured, but by and large rifle calibre AP was abandoned as ineffective.

Whatever the claims for AP in the report I suspect the rationale was to bolster morale. Practically the role of BESA was to suppress and KO was delivered by an HE round.

[Don Juan]

I am not sure about the origins of this story, or the effectiveness of 7.62mm AP rounds. IIRC the Germans had already issued an AP round to troops in 1916, not because they anticipated tanks, but to penetrate the armoured shields used to protect snipers and sentries. They did notm work against the Mk 1 tank. Now AP rounds could penetrate the Mk 2 tank, but the reason was because the mk 2 was built as a training vehicle and was built of un hardened steel. It was only used in Spring 1917 in desperation after the success of tanks on the Somme The mk IV was better armoured, but by and large rifle calibre AP was abandoned as ineffective.

Whatever the claims for AP in the report I suspect the rationale was to bolster morale. Practically the role of BESA was to suppress and KO was delivered by an HE round.

Really not sure about this. How thick was the armour of the Mk.I tank? What do you mean by "hardened steel"?

There were two basic types of armour used on tanks in WW2 - rolled homogenous (or "machinable quality") or face hardened (or "cemented"). Were either of these employed on WWI tanks? "Hardened steel" is a non-technical description, I think.

I'm far from convinced about the rationale for employing Mauser SmK being "morale". The claim that it could penetrate 12-13mm armour rings too close to the British declaration that 14mm face hardened armour was the minimum they could specify for their tanks in order to repel Small Arms AP. Look at the A9 and A13 Mk.I Cruisers, Vickers Light Tanks, Tetrarch, Daimler Armoured Car - all 14mm basis, except for the floor plates.

If the issue of Besa AP was for morale reasons, which is a reasonable proposition, then I would expect to see general pronouncements extolling its virtues in documents that RAC formations and units would have access to. So far, I haven't seen these (which is not to say they don't exist). The only reports I have seen that have commented on the efficacy of Besa AP have been the very high level reports I have posted here. They may be examples of the General Staff and Ministry of Supply actively attempting to kid themselves, but this seems to me to be a rather rarefied explanation. Also 2 pounder armed tanks did not have a HE round to deliver, so it was 2 pounder solid shot or Besa AP or nothing.

Again, the "morale" argument may have something in it, but that itself needs some documentary support, rather than supposition.

[Urmel]

I really cannot believe Sheldrake is still having this discussion based on nothing but his personal experience and supposition.

'Smk-sicher' is an accepted term in German. It appears to mean at least 13mm armour protection at 60 degrees off the vertical (?).

For post-war see:

https://de.wikipedia.org/wiki/Luchs_(Sp%C3%A4hpanzer)

For wartime see:

http://www.lexikon-der-wehrmacht.de/Waffen/panzer1.htm

During the war vehicles such as the Sdkfz. 25x series and the LWS II were designed with this in mind.

I also seem to recall from the history of the UK's 3rd Division that in Belgium in 1940 they undertook a counterattack using Carriers as stand-ins for tanks, and these were duly shredded by German small arms AP. But memory is very hazy on that.

[Don Juan]

Here's a two-for-the-price-of-one.

4 Pak 38's being destroyed by a combination of Besa AND 3" CS:

(from WO 201/554 9 Armd Bde report on operations, Nov. 1942)

[Juha Tompuri]

Does there exist any info about the British usage of SmK(H) at North Africa?

I think the question is whether the standard German SmK round would best qualify as a "ball" or "AP" round. If the latter, then that is probably what the British captured. If the former, then the British probably captured SmK(H).

On 11th February 1942, Captain D.M. Wilkie of the AFV Division at GHQ Cairo issued a memo stating that:

"In view of the great difficulties involved in the repacking of BESA belts it is considered that units equipped with BESA guns should be allowed a certain scale of GERMAN A.P. and A.P. Tracer ammunition and advised to re-pack belts on the scale of five per tank to include 1 A.P. and 1 A.P. tracer in every four rounds."

http://forum.axishistory.com/viewtopic. ... 5#p2028227
I think that the mentioned captured German AP-ammo might well have been the S.m.K. and S.m.K. L'spur. And/or their tropicalized versions S.m.K. trop and S.m.K. L'spur trop.

From my reading of the data, the SmK(H) round could most likely penetrate the 4mm+4mm gun shield of the Pak 38 from at least 500 metres.

So from Wiki, the SmK could achieve 12-13mm penetration (I assume at normal) 33% of the time at 100m, so for the 8mm gun shield of the Pak 38, I'll invite everyone to speculate.

Well... the PaK 38 shield is spaced and (mainly/often) angled. So 4+4 is (usually) more than 8 here, what comes to protection.

Regards, Juha

[Urmel]

I agree on the Pak 38 likely to be offering good protection. Spaced armour and rounded design. 3.7 cm not so much. Does anyone know the strength of the 88mm gunshield?

[Juha Tompuri]

Does anyone know the strength of the 88mm gunshield?

This site mentions them to have been 10mm thick:
http://www.worldwarphotos.info/gallery/ ... y/flak-88/

Regards, Juha

[Juha Tompuri]

I think that the mentioned captured German AP-ammo might well have been the S.m.K. and S.m.K. L'spur. And/or their tropicalized versions S.m.K. trop and S.m.K. L'spur trop.

AFAIK the L'spur tracers being (even) less effective in armor piecing.

Regards, Juha

[Urmel]

Does anyone know the strength of the 88mm gunshield?

This site mentions them to have been 10mm thick:
http://www.worldwarphotos.info/gallery/ ... y/flak-88/

Regards, Juha

Thanks! 10mm and only lightly angled would indicate it wasn't SmK-sicher?

[Juha Tompuri]

Thanks! 10mm and only lightly angled would indicate it wasn't SmK-sicher?

I think that 10mm armour angled to (judging from a photo) some 70°might just and just work against British used AP-ammo (SmK and their own).

Regards, Juha

[Juha Tompuri]

Thanks! 10mm and only lightly angled would indicate it wasn't SmK-sicher?

I think that 10mm armour angled to (judging from a photo) some 70°might just and just work against British used AP-ammo (SmK and their own).

8 mm for the SmK round and 13 mm for the SmK(H) round are for a 30° impact angle, as I posted. Cheriz made the mistake to list the 13 mm for 0° impact angle.

So 13 mm for 30° impact angle (original German source) and 18 mm for 0° impact angle (your data) are fiting quite well imho. The SmK round had a penetration of 8 mm for 30° impact angle and 10 mm for 0° impact angle listed (original German source).

http://forum.axishistory.com/viewtopic.php?t=84321

"The most exhaustive tests during the Second World War seem to have been carried out in Germany. Official penetration curves for 7.92 mm AP rounds tested in 1942 are worth examining in detail because they reveal the variations which can occur. The SmK-v (Spitzgeschoss mit Stahlkern verbessert; improved pointed bullet with steel core) achieved the following:
at 100 m: 12 mm / 90º, 8 mm / 60º, 3.5 mm / 30º
at 300 m: 9 mm / 90º, 6 mm / 60º, 3 mm / 30º
at 600 m: 6 mm / 90º, 3.5 mm / 60º, 1.5 mm / 30º

However, if the bullet first penetrated a 3 mm dural (light alloy) aircraft skin angled at 70º, armour penetration at 100 m dropped to 4 mm / 90º, 3 mm / 60º and 2.5 mm / 30º.
A different 7.92 mm AP loading, the Pz-v (Panzerdurchschlagsleistung verbessert; improved armour penetration) penetrated less than 11 mm / 100 m / 90º but was much more tolerant of unfavourable circumstances, achieving 9 mm / 60º and 4.5 mm / 30º. Even more significantly, after penetrating the same angled dural skin the Pz-v could still penetrate 8.5 mm / 90º, 7 mm / 60º and 3 mm / 30º. Clearly, bullet design made a huge difference.

These results are supported by tests carried out by the British in January 1941 to compare British and German rifle-calibre steel-cored AP ammunition. The performance of the .303" (11.28 g at 735 m/s) and the 7.92 mm (of unspecified type, but measured at 11.53 g at 788 m/s) was first tested against "homogeneous hard armour". The thickness necessary to achieve immunity from this ammunition at 183 m was 12.0 mm for the .303", 12.5 mm for the 7.92 mm, when striking "at normal" to the armour (i.e. at 90º). The British ammunition was significantly worse when the striking angle changed to 70º; only 6.6 mm was needed for immunity in comparison with 8.9 mm to protect against the German round.

The test then changed to shooting at the rear of the long-suffering Bristol Blenheim at the same distance, involving penetrating the rear fuselage before reaching the 4 mm armour plate protecting the rear gunner, which was angled at 60º to the line of fire. The results in this case were reversed; 33% of the .303" rounds reached the armour and 6% penetrated it. In contrast, only 23% of the 7.92 mm bullets reached the armour, and just 1% penetrated. The British speculated that the degree of stability of the bullets (determined by the bullet design and the gun's rifling) might have accounted for these differences.

The Germans helpfully tested other nations' ammunition as well, and this produced some surprising results. They rated the British .303" AP as capable of penetrating 9 mm / 100 m / 90º, but only 2 mm after first penetrating the angled dural skin (which contrasts sharply with the results the British observed). Comparable figures for the Soviet 7.62 mm API were 10.5 mm and 4 mm, but the API/T fell to a maximum of just 6.5 mm; the steel AP core was lighter as the tracer used up some of the space (a common disadvantage of small-calibre AP/T bullets)."

http://forum.axishistory.com/viewtopic. ... it#p658545

Regards, Juha

[Don Juan]

Bear in mind though that any gun shield is not going to be hit by a single bullet. In the case of a single Besa, the theoretical maximum is that the shield could be hit by 225 bullets in less than 15 seconds, 25% of which might be armour piercing. There's a lot of kinetic energy there, and in combination with AP, even ball might cause more damage than would normally be expected.

[Clive Mortimore]

Any field gun or anti-tank gun fitted with a shield only gives the crew limited protection. Many of the crew would not be behind the shield most of the time when the gun is in action. Fire a machine gun at the crew, those who were lucky enough to get behind the shield would not be able to operate the gun as normal. If attacked from the side the shield was useless. Hence the need for infantry to support the tanks and out flank any anti tank guns.

The British came up with a solution by having additional shields placed along the trails of the 6 pdr gun, this did give the crews added protection but limited the mobility of the gun when in action.

[Juha Tompuri]

Bear in mind though that any gun shield is not going to be hit by a single bullet.

Wonder why not?

In the case of a single Besa, the theoretical maximum is that the shield could be hit by 225 bullets in less than 15 seconds, 25% of which might be armour piercing. There's a lot of kinetic energy there, and in combination with AP, even ball might cause more damage than would normally be expected.

Depending on the distance, but that theory sounds more like a peace time firing range procedure.

Any field gun or anti-tank gun fitted with a shield only gives the crew limited protection.

Yes.

Many of the crew would not be behind the shield most of the time when the gun is in action.

I think that quite much depending on whether the gun is being dug in or not.

Fire a machine gun at the crew, those who were lucky enough to get behind the shield would not be able to operate the gun as normal.

As above.

Regards, Juha