(Rant) British 381mm APC is unusable, due to a combination of bad penetration and explosive filler just... not working.
The Shell 381mm Mk.XVIIb APC is complete garbage, and any ships which use it are unusable in their current state.
This is the best shell available to several 7.7 ships, HMS Warspite, HMS Hood, HMS Barham and Arkhangelsk with just 620mm of penetration. On paper, this is acceptable for a 7.7 ship, but in live matches is abysmal.
The shell is designed to be used in long-range plunging fire, but the maps rarely provide the opportunity for this. Against same-tier battleships, entire 8-shell salvos will non-pen armour of 7.0, 7.3 and 7.7 enemies at point-blank ranges of 6km and up to 16km away. for some reason, when you do penetrate, it only kills one or two crew like its a dud round or something. I swear that the explosive filler is bugged, even when it does penetrate and enter highly populated areas it does next to no damage.
In the game that prompted this post, I was firing salvo after salvo of these awful shells at a slightly angled USS. Wyoming, a 6.7 battleship with just 280mm of belt armour and one of the easiest BBs to kill by ammorack, from 6.5km away. only about a third of the shells would penetrate per salvo and these would kill at most 20 crew. In the after-battle shot log, I watched round after round of these fully penetrating rounds enter the ammoracks, explode, and then deal no damage. Just infuriating. The 13.5inch guns of HMS. Marlborough unironically perform better.
I personally can't wait to use Prince of Wales, with less than 600mm of penetration at 8.0. Surely having 14-inch guns with 100mm less pen than everything it faces will be a treat!