First time test

I bought these .303 British linked liked this several years ago. I remember that I pulled one at that time, and I think they are not tracers, but that is open to conjecture, as I cannot lay my hands on the round that I pulled.

The headstamps appear to be triple stamped, The best that I can make out is that they are all stamped 3A over 40 twice and 38 star over H once.

Does anybody have the story on these?