beefix:
I have now seen the 0.50 round (still live BTW) it has SL 43 stamped on the base. I wonder were it was made? I don't really want to kick this thread off again but all this is really interesting stuff.
In the few months that I have been a member of this board I have been amazed at the knowledge to be found here. I even at one stage thought of taking a screw (threaded type) off an aircraft and posting a photograph of it in this forum to see if anyone could identify it. I decided not to as I am certain that such a challenge would only last a few hours at best.
Joking aside, I feel sure that members of this forum will be able to give you full chapter and verse on the round in question.