I visited the Washington Navy Yard museum this past weekend, and out in front there are slabs of Japanese 23" armor that the placard said was taken from Yokosuka shipyard after VJday and was intended for the next Yamato BB. They took it to Dahlgren and fired 16" shells at it from 10,000 yards for ballistics analysis. Holeeee shit..... I wish I had taken pics. I had no idea what a 2700lb 16" shell could do to armor that thick. Penetrated all the way through, and what was left was totally molten, jagged piece of metal.