AFAIK that is correct. The LFP of JS-2 Mod. 1944 with cast hull had nominal thickness of 120mm, actual thickness varied due to manufacturing deviations up to 130mm. That reddit post is wrong.
Glad to see soviets are getting buffed due to their primitive manufacturing techniques while other nations who employed stricter tolerance on their products are getting shafted because of it.
LFP on the IS-2s is easily the biggest and easiest to hit weakspot, among the weakest two. That’s not the case now with IS-2 (1944)s and some people might still not know it.
It seems to be a generally accepted explanation that the thicker UFP on later Panther tanks is due to manufacturing tolerance, but I don’t believe this to be the case. +5mm is +6,25%, which is more than +5% max thickness tolerance used in German rolled armour manufacturing. No captured Tiger tank had 85mm thick sides. Also, we see this value again and again on captured vehicles, which is odd if we are to believe this to be a one off outlier.
Why was the glacis plate on later Panther tanks thickened? I don’t know for sure, but I have a theory. 80mm thickess is special as it sits right between 55-80mm interval of thickness and the 80-120mm interval with each having different specifications for (among other things) hardness.
Spoiler
Adding 5mm to the plate wouldve placed it into the “85-120mm” category meant to have lower hardness than preceeding interval. This would help improving the ballistic resistance against large caliber shell at large angle, but decrease resistance aganst small shell coming at low angle, but this would be unimportant as the Panthers UFP was mounted at 55° and would almost never encounter shells at lower obliquity.
So, if this was the only reason, then why didn’t they just manufacture softer 80mm plate just for this purpose? Well, idk. Which is why this is only a theory that needs more research to be viable explanation.
They are so desperately trying to morph this mediocre piece of junk into a King Tiger equivalent that it is not even funny. I guess this is where the stolen armor from the Maus turret front & Stug III A/F ended up at…
We should always take these intelligence reports with a grain of salt, otherwise we have to conclude that driver’s plate on JS-2 is only 105mm thick and angled 16°.
Russian Wikipedia says that driver plate had several variations casted/rolled and with different thickness. Some researchers says about 6 different modifications.