British 9mmP production started in late 1941 and most collectors are familiar with the various R^L 41 rounds, both ball and drill, made at Royal Laboratory. There is also an early ROF BLackpole ball round headstamped “B^E 41 9M/M” which is typical of later production and has a purple annulus and a ringed cap. I have had one of this type for a long time.
I have just acquired a variant of this that must pre-date it. It is also headstamped “B^E 41 9M/M” but the headstamp is asymmetrical and looks like it was originally meant to be a four position headstamp, perhaps with “IZ” in the vacant 4 o’clock position. It has no annulus colour and the cap is unringed. The specification was altered to include ringed or staked caps on drawing DD/L/11833A in October 1941.
What is even more interesting is the difference in bullet ogives. Both bullets are nominally 115 grains (115.4 and 116.8 grns).
In the attached pictures the left hand round is the one with the asymmetric headstamp.
Lew, have you seen this variant?