Since we are on the subject, I dug out The Book, and scanned The Photo. Taken from a 1939 textbook from the U.S. Naval Academy. This one photo shows the super rare and ultra rare of the old U.S. Navy ammo that preceeded that date. The file size limitations of BOCN attachments wash out the details of the signage on the rounds so I will list them.
Back Row L-R 6" 40 CAL SHELL SEMI FIXED, 5" 40 CAL CARTG. F.N. SHELL, 5" 40 CAL CARTG. F.S. COM. SHELL, 5" 40 CAL CARTG. A.P. SHELL, 4" 50 CAL CARTG. F.N. SHELL, 4" 50 CAL CARTG. F.S.COM. SHELL, 4" 40 CAL CARTG. F.S.COM. SHELL
MIDDLE ROW L-R 3" 50 CAL CARTG. ILLUMINATING STAR SHELL, 3" 50 CAL CARTG. F.S. COM. SHELL, 3" 50 CAL CARTG SHRAPNEL, 3" 50 CAL CARTG F.N. SHELL, 3" DAVIS GUN CARTG F.N. SHELL, 3" 23 CAL CARTG. F.N. SHELL
FRONT ROW L-R 1 PDR CARTG. F.S. COM. SHELL, 3 PDR CARTG. F.S. COM. SHELL, 6 PDR CARTG. F.S. COM. SHELL, 3" F.G. CARTG. SHRAPNEL, 3" 23 CAL CARTG. SHRAPNEL, 3" 23 CAL CARTG. F.S. COM. SHELL
I have never seen any real or dummy F.N. projos (Flat nose). They were designed to be anti-submarine projectiles, with the flat nose so they wouldn't richochet off the water. This is the only photo I know of that shows them.