Interesting

[Alan de Enfield]

I reckon Surpmil your right, perhaps the stabs wore worn and it colletid the neck instead of the indent stabs being performed, it stands to reason with the millions of rounds being churned out that these anomalies would occur.
How many got through I wonder as Q/A inspection may have ditched them as not being as designed so may alter the way the round performed (It would not really) but someone's life depended on how it did work so it they would have been binned it.

Bindi2 be good to see a pic of that one!

In the UK every single round was inspected by MK1 eyeball and individually weighed, but I don't know it they'd have picked up your 'ring'.

6-8 'lines' per shed, how many sheds per manufacturer ?