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Here's a perspective:Does anyone have data on how the Russian 76mm compared to their German / American equivalents?
There is annecdotal evidence of the impact of the T34 being impervious to AT fire - unless it was the 88mm!
Trends in Soviet Metallurgical Developments
Central Intelligence Agency
Washington 25, D, C.
16 April 1953
Watertown Arsenal for metallurgical examination
The very high hardness encountered in most Soviet tank armor has
caused much unnecessary concern regarding the relative ballistic performance
of the hard Soviet armor and the softer American armor. Many
people associate high hardness with high resistance to penetration.
Although this is true, within limits, in the case of attack of armor
by undermatching projectiles (i.e. caliber of shot is less than the
thickness of the armor), articularly at low obliquities of attack, it
is definitely not true when the armor is attacked by larger caliber
shot at higher obliquities of impact. Competitive ballistic trials
which have been conducted at ordnance proving grounds on both very hard
and normally hard domestic armor and Soviet armor have established
beyond question of doubt that in many cases, representative of actual
battlefield attack conditions, very hard armor is distinctly inferior
in resistance to penetration as compared to armor of more conventional
hardnesses (280-320 Brinell).
Нос корпуса
Выбранная конструкция носовой части корпуса танка ИС-3 аначительно увеличивает снарядостой-кость этого узла по сравнению с носовой частью серийного корпуса ИС-2, за исключением передней наколонной част и крыши корпуса.
Верхние лобовые листы корпуса ИС-3 полностъю зацицают экипаж от 88мм немецких бронебойных снарядов с дистанция 100 метров и более, при любых углах обстрела.
Верхний лобовой лист корпуса ИС-2/Уралмашзавода/ непробивается толъко дистанции 600 метров и далее.
The M47 with 102mm@60 was penetrated by the 88mm/L71 out to 250m but it only had 210 BHN armor.This doesn´t explain why the T54 glacis wasn´t penetrated at all even from close range. It doesn´t need to. The T54 is a younger, more advanced metallurgical design. It benefitted from all late war research conducted and the data gathered in Germany and abroad which helped to produce the best plates for a specific purpose.
I guess no flaw in that JSII armor.
It is possible, that only the surface was hardened, probably by additional heat treatment. It�s then kind of face hardened (but not true, as there is no ski-ramp like change in hardness gradient in the section, just a thin, hardened surface with an abrupt drop to normal plate homogenious hardness levels, which under dynamicly applied impact force is guaranteed to be flawed.One odd thing is that while the front plate lists the BHN as 444 the tensile strength is equivalent to 295 BHN.
T-34. Decent gun but the fighting effectiveness was limited by the vehicle commander also being the gunner. GREAT armor for the wt by late 41 standards. This armor advantage was surpassed by the Germans fielding better and more guns.
Compare it to the 88 projectiles for 3000 + velocities vs targets.
8" plate@ 0°:Two complete (NBL) penetrations with projectile passing through plate. 3124mv and 3257 mv.(550y/90y) Two ABL penetrations. Projectiles Intact. 3001 mv 3038 mv. (990y/860y)
6 1/16" plate@ 30°:Two complete penetrations, projectile through plate. Projectile intact 3008 mv 2971 mv (974/1100y)
5 1/8" plate@45°: One complete penetration, projectile through plate. Projectile fractured. One projectile shattered. 3288 mv 3211 mv
3 7/16" plate@ 55°: Two complete penetrations. both projectiles fractured. Projectile fragments passing through plate.
One partial penetration projectile fractured.
3334 mv on two penetrations. 3310 mv on 2.5" deep partial.
All the science and number-crunching! Good reading, but in the field, only rough ideas. Much of what gets penetrated, or not, can be influenced by compound angles (armor angles AND angle of the target to the angle of the gun as well as the hull angle to the horizontal due to terrain). Add some stowage on the tank, "smart" stowage aka goodies purposefully placed, track section, road wheels, and the like.
T-34. Decent gun but the fighting effectiveness was limited by the vehicle commander also being the gunner. GREAT armor for the wt by late 41 standards. This armor advantage was surpassed by the Germans fielding better and more guns. But what the Germans could field, the Russians were able to field many times over and in places the Germans had little heavy forces to counter with. Better was the T34/85 with the 3-man turret and the more useful 85mm gun. On par with the US 76 and broadly close to the PaK40 in penetration, the 85mm gun had more useful HE round for BREAKTHROUGH.
NOT A SINGLE US Sherman that landed in NORMANDY was armed with the 76mm gun! All were at the depots in England, refused by the Armored Divisions. I do not recall the number present/sitting at the depots, but I seem to recollect 250-400 units. One must ask WHY? The first reason was that the 75mm gun had done well so far. Most of the combat was against infantry or strongpoints where the 75mm HE round was vastly superior to the US 76mm HE round. Another factor was Intel! Part of this was US believing the Panther was of limited production such as the Tiger I. I believe it was not long before D DAY that the alarm as sounded that the Panther was actually is wide-scale production.
Let's talk Sherman Firefly. At Normandy and until late war, only 1 in 4 were Firefly conversions. Then consider the all-powerful 17pdr had some bad ammo lots early-on. Some rather embarrassing results at a test shoot in Normandy. You cannot penetrate what you cannot hit! Once this was sorted out, a very respectable performer. Firefly tanks were a priority German target indeed. The 17pdr AT gun was less successful as the size and weight limited mobility.
Consider the lower rate of fire for some of these big guns and or slow traverse rates. Consider the reliability, mobility, and quantity. Tanks are no good unless they are running and fully-mission-capable. They are not good if stuck in the mud, have a busted final drive, or out of fuel! Must shoot, move, and communicate!!! On a tank, it is the package of all the characteristics. The big wild card is crew quality, training, and tactical sense. From the Operational Commander, down to the BN Cdr, Co Cdrs, PLs, vehicle commanders and the vehicle DRIVER! Taking on the COMBINED ARMS concept, lots of tactical air power and artillery make up for not having great tanks.
I got this from tank.net a few years ago. Aberdeen tests of 88mm/L71.