
The picture shows an unfired but distorted (exploded) primer with a diameter of 35mm / 1.4". It was found, along with others on a beach near Harwich, UK.
I am familiar with this type and size of primer from the base of a 3" 20cwt cartridge case, but was this a standard primer used in other cartridge cases or just the 3"? Also, why two dates on this kind of thing?