I was recently given 2 casings from WWII. A 3 inch and a 5 Inch. I am interested in finding out about the 5 inch 51 cal. How it was used and how common is it. The full stamping on the base is 5-IN-51 CAL MK3 CATAPULT N.S -3-1942 - JCA (US anchor symbol) Lot 49.
The primer has been removed but I do have the cork cap. I’ll upload some photos as soon as I can