I am one of those sad subjects that collects ammunition, in particular 303's. I have numerous books and reference material but this came with a lot that I bought a couple of weeks ago.
Strange markings on the base (Australian?) and the head has 4 symmetrical splits down the sides with a flat top?
Flat top usually, but not always suggests an early round, with the absence of a proper code or a date code I'm a little stuck, so any ideas however bizarre would be appreciated Thanks