I own a Kongo tier V Japanese battleship, I regularly meet St. Louis class cruisers.
I shoot them with AP: couple of hundreds of damage, probably due to over-penetration.
I shoot them with HE: couple of hundreds of damage, knocks out some modules.
How do I freaking kill them? With a good hit on a battleship with AP I can take 20k of their health, how comes that ship is so invulnerable?