I was amazed when I saw a 406mm Soviet cannon shell, from a 406mm system supposed to be installed on "Sovetskiy Soyuz" battleship... This cannons were used in defence of Leningrad. Witnesses said that with a lucky hit they tore apart a whole tank platoon!
Can't even imagine a 468mm shell...
My father was a navy cadet in 1943-1948, and in 1944 he served on board of "Archangelsk" battleship, former British "Royal Soverign", in Northern Fleet.
"Alexandrov's battery" in Sevastopol was made of "Empress Maria" Black Sea Fleet battleship sunk by German agents in 1916. 3-barreled 12" turrets defended Sevastopol. Nazi heavy artillery was unable to hit the turrets, and Stukas were unable to destroy them too. They were a huge nail in the bellybutton for nazies. Finaly, when they ran out of shells, and nazi infantry attacked them - they simply shot without shells, with flame stream burning everything for 300m...
"Marat" battleship, "Sevastopol" type Baltic dreadnaught, was hit by Rudel's Stuka, right into the first exaust pipe, and lost the nose part with turret #1. Remaining three turrets, total 9 12" cannons continued to fire at the enemy...
Old artillery ships are my old love. Every time I am in Leningrad I get some time to visit "Aurora" cruiser, the world's oldest war ship still afloat. It's fantastic to stand on the deck of a cruiser that was built 100 years ago and survived Tsushima battle...