The final question is about a little round I have had for over thirty years. When I was given it (by a non cartridge collector) I was told it was an adaptor cartridge. Whilst I very much doubt if this is true, the bullet diameter and large rim do add a degree of crediblity to this claim.
Overall length 1.383" (35.12mm)
Case length .902" (22.92mm)
Bullet Diameter .307" (7.82mm)
Neck diameter .324" (8.30mm)
Head diameter .374" (9.50mm)
Rim Diameter .472" (12.00mm)
It is difficult to give any shoulder dimensions because of the shape of the case, but the length of the neck is about .265" (6.73mm).
What is intriguing is the headstamp, “Zi-Di.”