Soviet 100mm AP performance (vs Ferdinand)

[ww2steel]

This test started out as part of a series of tests pertaining to how CMBB applies appliqué armor (no pun intended). First I tested the Pz38(t)E and G models (25+25 vs. 50mm frontal armor) against the AP from the 76.2 L/23 Mountain gun and found that, at least against that weapon that the G model is protected equally to a little over 300m out. Two different ways of calculating it put the E model at 47mm +- .5mm of equivalent armor thickness relative to the G model. This is significantly different from what the BF staff told me about how appliqué is generally calculated (base + .5*appliqué) which should yield only 37.5mm armor thickness. These results were based on the findings are the results of 1300 frontal impacts out to 1100m.

Enough base info. This test I wanted to measure the difference in performance between the Ferdinand's hull and superstructure- the hull is 100+100, the superstructure a single 200mm plate (converted for normalized angles). I have not had time to crunch the numbers on that yet, but I was surprised how crappy the 100mm BS3 (and presumably SU100) ammo quality is modeled! I am not arguing penetration values but rather the ammunition failure rate. Now I know, these vehicles could never have met in combat, that's not the point, I was simply testing this with May'45 ammo and it's the only thing that should reliably penetrate the front of this vehicle. I think I remember the gun being tested against an Elefant though. Now, CM seems to be using (correctly) the early ammo, BR-412, which was a sharp point, uncapped AP shell. This should be perfect against the lightly sloped, soft naval armor of the Ferdinand.

It's not.

I tested 985 impacts, 917 of which struck the armor package (the others were gun/ track). These tests were from 0 to 1000m in 100m intervals and at 1500 and 2000m. Out to 700m ALL non-penetrating hits caused the shell to break up. At 1000m 82% broke up, 1500m was 42%, 2km was 16%. I was just surprised at this, but I guess even against this soft armor the uncapped round will tend to disintegrate.

I had similar break up results against the Panthers in a separate test (another forum post).

I only had four full penetrations, at 200m or less. There was even an additional FP at a weak point at 700m!

Partial penetrations totaled 46, plus one more weak point.

Ferdinand Impact breakdowns:

Superstructure: 33%

Upper Hull: 49%

Lower Hull: 12%

Gun: 3%

Track: 4%

I'll post more when I have time, hopefully tonight. Anyone with info on the wartime BR-412 round, please post. I have looked over Battlefield.ru and many searches, but found little on ammo quality (other than that the -412B was unsatisfactory).

Gotta go to work! Happy New Years!

Mike

[John Kettler]

ww2steel,

Please cite your source re "soft naval armor" of the Ferdinand. German naval armor is NOT RHA. To the contrary, German naval armor is cemented/face-hardened, as detailed here by naval gunnery effectiveness grog Nathan Okun.

http://www.chuckhawks.com/armor_schemes.htm

Here is a further discussion of both U.S. naval armor as compared to German and also weapon-target interactions when various armor types met various types of AP shells.

http://www.navweaps.com/index_tech/tech-017.htm

Table II here gives some useful data on BR-412 performance.

http://www.battlefield.ru/content/category/6/33/49/lang,en/

Chevan's post here seems directly applicable to your question.

http://www.ww2incolor.com/forum/showthread.php?t=4409

Zaloga discusses the BR-412 family in the paragraph here directly above Combat Engineer Tanks

http://books.google.com/books?id=tbZhcjy0-5IC&pg=PT18&lpg=PT18&dq=russian+br-412&source=web&ots=EZmezCuyWh&sig=_s8XYLKDqGO9bu7JvtB6UXm6FMY&hl=en&sa=X&oi=book_result&resnum=6&ct=result

Here's a good discussion of what the Russians were using as a test target, together with other juicy metallurgical grog stuff. Also included is a single range/penetration figure for BR-412.

http://forum.axishistory.com/viewtopic.php?f=47&t=38723

Two data points on BR-412B fired from BS-3

http://en.wikipedia.org/wiki/100_mm_field_gun_M1944_(BS-3)

BR-412B and more

http://www.tarrif.net/cgi/production/all_penetration_adv.php

Regards,

John Kettler

[ww2steel]

Gotta work early tomorrow, so being brief. I almost gave up when I finally refound this forum post with a lot of info from Robert Livingston (if I understand right the CM armor engine came from him and Lorrin Bird (Rexford), based on the De Marre equation).

We all know it's soft, but as to where it came from...

The partial quote:

A captured Ferdinand in Russia was measured at 212-223 BHN on its 86,

110, and 200mm plates (Brit intell, 16 Feb '44). Spielberger tells us

that the plates for the Ferdinands were taken from Naval stocks, which

could mean it was made to different specs. German 85-200mm specs at the

end of the war called for 220-266 BHN. 55-80 was 250-290, and 35-50mm

was 300-350 BHN. Much armor in that range was face hardened, with a

450-600 BHN face. The German specs point out the general relation

between optimum hardness related to plate thickness with respect to

attack by late war KE weapons capable of having a chance of defeating the

armor. The USA developed similar specs by the end.

From this (very cool) forum thread:

http://yarchive.net/mil/ww2_tank_armor.html

Armor grogs will enjoy! Livingston lists his sources there, but I cannot find this report anywhere, all I managed to download is the table of contents.

Well, I just searched my bookshelf for "Heavy Jagdpanzer" by Spielberger, Doyle, and Jentz. Thought I had it but can't find it.

http://www.amazon.com/Heavy-Jagdpanzer-Development-Production-Operations/dp/0764326252

If I remember right the normal armaments industry was not capable of producing plates over 100mm thickness to tank specs (nicely face hardened RHP). If anyone knows more or has that book it will probably say more.

Thanks for the links, I'll enjoy looking through them tomorrow!

Mike