I am currently trying to dig up a variety of steel core Czech ammo to find a core that matches my DDR core. I am going to go out on a limb here and hypothesize that all PS (x, ^, aym, balls, PS, Z, etc.) rounds will have cylindrical cores and S&B (bxn, O) might have cylindrical or mushroom-shaped cores.
Another consideration has come to light. My current manufacture S&B rounds have non-magnetic jackets and I’ll assume lead cores, required for importation into the US. However, I have a few modern S&B examples of Proof rounds that have magnetic jackets or steel cores. If Odd-Job’s mushroom-shaped cores did come from modern S&B ammo there might be some sub-contracting going on for “Europe Only” ammunition.
Many questions…too little time for all the answers!
Welcome here, from one new guy to another. Thanks for posting your input here, I value it greatly.
@ Jon C
If you have an actual DDR insert in your possession, could you please post an image of it and its dimensions and weight? That would go a long way to excluding/including it as a line of investigation for me.
Of course the ideal situation would be if I could get an actual sample of one of those rounds. Do you have extras, or know who has extras that I can purchase?
One other thing I might try, is analyse a photograph (if you can provide one) of an S&B insert alongside a DDR insert.
It is incredibly frustrating for me to hear about this DDR insert but not to see it or be able to X-ray it.
Another lead that I am following is steel .22 inserts (I saw a cartridge posted on Rimfire Central and I am looking into it).
Thanks again for the help that everybody is providing.