British 75mm MkV tank gun

[CharlesM]

I am Charles Markuss, one of the researchers for the ASL system. M72 AP was solid uncapped shot designed for use against homogeneous armour. By the time it was in service with the British in the M3 the Germans were using face-hardened armour against which the M72 often shattered, like the 40mm 2-ponder AP shot. Theoretically the round was APHE but at the time the USA had no suitable fuze for it. The British therefore simply filled the cavity with inert material to boost AP performance, and did so even after a fuze appeared because the first batches at least were very unreliable. M61 was, as stated, APCBC designed for use against face-hardened armour which was still in use on some parts of German tanks, especially the cats. The US army considered developing an APCR round for their 75mm but the performance increase would have been marginal and really a waste of precious tungsten. If they ever seriously considered it (doubtful) I suspect that the British felt the same way about attempting to develop an APDS round for their 75mm as factories were at full capacity producing 6-pounder and 17-pounder APDS. Moreover, as stated already, I doubt whether the guns would have withstood the chamber pressures of more propellant behind the projectile. APDS is of course also hazardous to friendly personnel. The British and US 75mm guns werre really designed for HE and WP.

Incidentally the US army was given 6-pounder APDS for their 57mm gun by Britain but due to the scarcity of targets only about 180 rounds were ever used in Italy, and something over 11,000 in NW Europe.

[chuckfourth]

Hi Charles
I would be verry interested to know which German vehicles had face hardened armour and on which surfaces. I have had some thoughts on the matter myself see.
http://www.shrapnelcommunity.com/thr...b=4&o=&fpart=1
I think that PZ IV turret is face hardened, and the cats side and rear armour was face hardened, also and I believe sdkfz 231 and 232 came in face hardened armor? do you know if this is correct?

[CharlesM]

Leave it with me for a few days.

Regards

[CharlesM]

Churchill units often had a troop of 4 M10 76mm or Achilles 17-pdr SPs attached for this purpose. There was a drive to fit as many 75mm guns before D-Day to Churchill Mk IVs (only one Mk III went to Normandy), turning them into Mk VIs. This was done by issuing conversion kits fitted in the field. Once the AP deficiency came to light some 6-pdr Mk IVs were retained, though by D-Day some units were completely equipped with 75mms - 6th Guards Tank Brigade being one.

[CharlesM]

I've done some checking, and what I said earlier about the cats is not quite right (see below). Face-hardened armour was used on the 4, 6 and 8-wheeled German armoured cars, i.e from SdKfz 221 through to 234 inclusive.

Pzkfw III Ausf G onwards and IV Ausf F1 onwards had face-hardened frontal armour, except for the glacis which was homogeneous, presumably because the slope was so shallow that the extra hardness was not needed, except for the glacis on the Pzkfw IV Ausf D, which had only this plate hardened, but throughout, rather than just face-hardened. PzKfw III Ausf G onwards and IV Ausf F1 onwards had face-hardened upper and lower hull sides, but not turret sides or on any rear armour plates. The last 50% of PzKfw IV Ausf J had only homogeneous plates.

For Panthers it is a bit more complicated, and made worse by the fact that the armour on many Panthers (about 50%) was of poor quality dut to bad heating and quenching processes. Bear in mind that all notionally on PzKfw IV and Panther were often actually 82-85mm thickness. The notional 60mm plates on the Panther nose were usually 65mm, later up to 75mm.

Panther Ausf D had glacis and nose armour face-hardened, aslo upper and lower hull sides. Nowhere else. Panther Ausf A had a face-hardened glacis (poor quality) and a face-hardened nose plate, and face-hardened upper and lower hull sides, but from 9/43 only homogeneous plate was used. From the sdummer of 1944 about half of the Panthers produced had flawed glacis armour. One other reason apart from poor heat treatment may have been the reliance on carbon as a hardener as non-ferrous metals like nickel and chrome dried up. The Panther Ausf G therefore had only homogeneous plate, and again with a glacis plate that often cracked under impact.

Tiger I armour was of better quality, as it was produced earlier in the war, and appears to have always been homogeneous. Tiger II armour was also only homogeneous, but of inferior quality for the reasons already given. Jagdpanther armour was softer that Panther armour, and so less prone to cracking.

Let me know if you want sources.

[chuckfourth]

I see, very interesting. Thanks very much for this detailed reply. If I might dig around a bit further?
Do you think it might be possible that the 250 and 251 half tracks had face hardened armour? after all the plate thicknesses were the same as the armoured cars. Also Im surprised the early panzer III's wernt face hardened, being the MBT and all.
Ive also heard mention that panzer 1 is face hardened and I would speculate the pz 2 may have been as well?
This site
http://ourworld.compuserve.com/homep...s/Specs-02.htm
disagrees slightly as it mentions that pz 4 had face
hardened side turret armour? (f1 onwards)
I would indeed be keen to have a look at the references as well if thats possible.

Thanks in advance Chuck.

[CharlesM]

I can't find annything that mentions face-hardened armour on halftracks.

As for PzKfw IVs, it seems to depend on sources.

My previous post about German tanks is from Lorrin Rexford Bird and Robert D. Livingstone, World War Two Ballistics: Armor and Gunnery, 2nd edition, Overmatch Press, Albany NT and Woodbridge Conn 2001. No ISBN is given.

No two sources seem to agree on the PzKfW IV,and Tom Jentz's Osprey New Vanguard # 39 on the PzKfw IV Ausf. G, H and J is rather vague when he describes the Ausf. G as having face-hardened 50mm frontal armour and 30mm side plates - implying that the turret sides were also FH plates. The earlier Osprey Vanguard # 18 by the late Bryan Perrett mentions FH armour only in the context of British examination of a captured Ausf. E. The applique armour over the hull MG mounting was FH, as were "the port armour covers". The 20 + 20 mm hull sides were not FH.

This lack of consistency is not surprising and not unique to German AFV construction - much would depend on the availability of FH plates during construction. Bear in mind that FH was an expensive exercise as a large number of plates were cracked and had to be discarded, and ultimately the game was not worth the candle, especially as plates became progressively thicker in the gun / armour race.

[cbo]

Pzkfw III Ausf G onwards and IV Ausf F1 onwards had face-hardened frontal armour, except for the glacis which was homogeneous, presumably because the slope was so shallow that the extra hardness was not needed, except for the glacis on the Pzkfw IV Ausf D, which had only this plate hardened, but throughout, rather than just face-hardened. PzKfw III Ausf G onwards and IV Ausf F1 onwards had face-hardened upper and lower hull sides, but not turret sides or on any rear armour plates. The last 50% of PzKfw IV Ausf J had only homogeneous plates.

According to Spielberger: "Begleitwagen Panzerkampfwagen IV", all the 30mm thick frontal armour plates on the Ausf. D were to be facehardened. That would be the front lower hull plate and the front upper hull plate as well as the front turret. Of the additional 30mm armour plate that were bolted on to the front of the Ausf. D in the summer of 1940 the first 100 sets were face-hardened, the reminder homogenous steel.
In the Ausf. E, all 30mm plates were to be facehardened while the thinner plates as well as the 50mm plates were homogenous. It appears that this also applied to the add-on 30mm plates on the upper hull front.
In the Ausf. F, the goal was to have most front and side plates facehardened, which, judging from the British reports used by Bird & Livingston, seems to have been carried out. This reference states that the turet sides were not face-hardened, while Spielbergers book seems to indicate that they were - even the turret hatches were to be face-hardened.
The Ausf. G was basically and Ausf. F with a different gun and it seems that it carried on with the same face-hardened plates. The additional 30mm plates on the hull front were face-hardened according to Bird & Livingston, Speilberger remains somewhat unclear on the matter
The Ausf. H started out as an odd mix, as the earliest vehicles had the same front armour configuration as the Ausf. G (50mm basis with 30mm add-on armour), then gradually started to get 80mm plate on the lower front hull, then the upper front hull. These 80mm plates appear to have been for the most part homogenous plates. Ausf. H production started in May 1943 and the decision to go with 80mm homogenous plates had been made even before that.
This would appear to have left the Ausf. H with 80mm upper and lower front hull homogenous armour, face-hardened side hull armour while the turret would have the front and mantlet face-hardened and possibly also the sides.
With regards to the Ausf. J, it was ordered in June 1944 that starting August 1944, all previosly face-hardened plates should be made in homogenous steel.

cbo

[Cross]

If the British 75mm Mk.V and US 75mm M3 were almost identical, and used the same ammo. Why does the US M3 have PEN 10 and the UK Mk.V only PEN 8 in the game?

In the case of the M72 ammo, according to an earlier post on this thread, the Brits even improved that round, giving it a higher penetration.

I looked at a couple of penetration sources, and they say there was virtually no difference between the M3 and Mk.V. In one case they gave the M3 a much poorer penetration than the Mk.V with APCBC M61 rounds, but I suspect that was an error of some sort.

I know the Mk.V did not have great AP ability, but it should probably be better than it is in SP, and surely should be no different from the M3?

Or am I missing something here?


Cross

[Mobhack]

Originally Posted by Cross

If the British 75mm Mk.V and US 75mm M3 were almost identical, and used the same ammo. Why does the US M3 have PEN 10 and the UK Mk.V only PEN 8 in the game?

In the case of the M72 ammo, according to an earlier post on this thread, the Brits even improved that round, giving it a higher penetration.

I looked at a couple of penetration sources, and they say there was virtually no difference between the M3 and Mk.V. In one case they gave the M3 a much poorer penetration than the Mk.V with APCBC M61 rounds, but I suspect that was an error of some sort.

I know the Mk.V did not have great AP ability, but it should probably be better than it is in SP, and surely should be no different from the M3?

Or am I missing something here?


Cross

If you think the UK gun should be equal to the US one, then please provide some data to support your case.

I think the AP data for that gun is just one of those things that have been in the game data since the SP1 days, and its never been challenged/evaluated.

My opinion is that since it is the same ammo from the same sized tube, you are probably quite correct.

Cheers
Andy