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]

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.

[Cross]

oops just noticed an error on my spreadsheet.

The averages for the Mark V, APC M61 ammo say:

500: 81
1000:63
1500:59

They should be:

500: 84
1000:82
1500:73

but once we get to cm it doesn;t effect the 500 range result, and only pushes up the 1000 and 1500 result by 1


Cross