About tank guns and amunition, hope it will be interesting topic :-)
In penetration data I will base on russian sources -they are ussaly most credible (the best). I will ussaly give value for monolith steel plate slopped on 60@ - it's the best scenario for APFSDS penetrator. In sucht scenario (slopped on 60@ plate) penetration value can be bigger at even 17-20% then on 0.degree plate - this is caused by "asymmetry loads back surface" of the plate):
Polish numerical simulations for the new APFSDS round against stacked RHA plates and complex targets:
1. stacked RHA
2 - 4. spaced armor arrays
5. spaced steel plates with rubber interlayers (no empty space)
6. ceramic tiles and RHA
Targets 4 and 6 cannot be penetrated, but the rest can be defeated.