I’ve been meaning to bone up on this and mention it for a while. I’ll just throw up some numbers and I’m sure everyone will pick up what I’m puuting down.
M4A1 Sherman front armor 100mm, rear armor 15mm. AAM defense 5/4
KV-1 front armor 100mm, rear armor 75mm. AAM defense 6/6 with hulking mass SA. My favorite Russian tank BTW.
IS-2 front armor 150mm, rear armor 60mm. AAM defense 7/7 with superior armor 2 SA.
The IS-3 's front plate was 200mm I’m not sure on the rear. 100mm comes to mind but I’m probably wrong. Regardless it wasn’t 200mm. AAM defense 7/7 with superior armor 3 SA.
Jagdpanzer IV/48 front armor 80mm, rear armor 20mm. AAM defense 5/3 with superior frontal armor 2 SA. A Sherman is nearly twice the height of a Jagdpanzer IV so I get the frontal defense thing when comparing the two. You also have to consider armor slope, round traps, mantlet thickness and shape, turret vs no turret etc.
The Carro Armato has the highly flammable SA. Early Shermans brewed up all the time. That’s why the Germans called them Tommie cookers. After water jackets for the main gun round stowage were introduced this problem nearly went away. I don’t think the water jackets were on the M4A1. Feel free to correct me if I’m wrong.
A well placed shot to the rear of a Sherman using a Mauser with AP bullets could stop a Sherman. Rear defense 4 my a$$.
I did reference some of the armor thicknesses from David Miller’s awesome book “The Great Book of Tanks”. If you don’t own a copy and like armor you need to get to the book store.