In the early 1960’s, when I was still at College, I visited Cecil Purcell, Gunsmith at 10 Worcester Street,Gloucester.
Displayed in his window was the scale model of a 15” naval gun in its mounting. The barrel was perhaps 18” long and stood next to it was a .22 Hornet cartridge. My impression was that it was capable of firing .22 Hornet but I am not sure that I ever confirmed that with him.
I believe that he had served in the Royal Navy in the First World War, working the full size 15” guns.
Also stood in his window was a large bore brass Paradox cartridge. I remember being puzzled by the large circular groove which I now know was used to crimp the waisted bullet
