No, I’m NOT reigniting the debate over whether or not these were MEANT to have the bead in or done to identify them as ballistic rejects - everyone has their side of the fence on that one - but I did want to show ( like my comments on the lot stamping method ) the sort of tools probably used to create the bead.

The above machine is a "bead roller". these are used to roll a stiffening bead or rib or ridge into a piece of sheet metal and are standard equipment for the metal fabricator. Possibly a mechanical version of one of these would have been used to roll the bead into the shells. This is the same way the rolled edge was done on the M35 / M40 models, just with different dies.

Of interest is that the various manufacturers did not have the same machines - or dies. We know this because the beads are different shapes.
Look at the following ……

Anyway, there you go - another bit of helmet trivia from ‘Downunder Dan’

Cheers all!!cool militaria

Click to enlarge the picture