ORIGINAL: kfsgo
ORIGINAL: crsutton
As an aside, it's astonishing how widely the penetration ranges on 6" guns vary, particularly outside the USN - compare:
USN 8in Mk. 9 - 300 (pre-war CAs)
USN 8in Mk. 12 - 282 ('new' CAs)
GBR 8in Mk. VIII: 278 (all 8in CAs)
IJN 20cm 3YT: 291 (all CAs)
USN 6in Mk. 12 - 140 (Omahas)
USN 6in Mk. 16 - 169 (modern CLs)
IJN 15cm 41YT - 86 (Aganos)
IJN 15.5cm 3YT - 222 (Oyodos - not that they're ever likely to do anyone much good, but what a difference that extra .5 makes, eh?)
GBR 6in Mk. XXIII - 121 (Leander, Town etc)
GBR 6in Mk. XII - 108 (Letter CLs)
DUT 15cm No. 6/9/10/11 - 86 (everything)
I can't say I've ever seen a 6in shell that wasn't coming out of a Mk. 16 penetrate a Japanese CA, but that's just in a bunch of faffing around with mini-scenarios so, y'know, anecdote not data. I'd definitely be very leery about taking them on even with more guns' worth of the Brit CLs, which is a shame as there's quite a few of them.
Well, from my experience the modern Allied 6 " guns fire more often and land more hits. (makes sense with autoloaders and fire control) but rarely penetrate on any hull hit. They do penetrate and do damage when they hit a Japanese CA in the superstructure. If they can get some early superstructure hits on the CAs in a battle, then the Japanese CAs really start shooting poorly, but sometimes it drives me crazy as they rack up a number of hull hits and do nothing. That can really turn a battle into a Japanese win.