Blue Ink on .303 primers

[BMG50]

Does anyone know the type of ink used seen on the outer edge of the primer of .303 or 7.62. rounds.

 

[TimG]

A Blue Annulus on .303 would indicate it is Incendiary, are sure it's not Purple? which would indicate ball. Any annulus colour varnish I suspect will be one of the many "R.D." (Research Department) formulations.

TimG

 

[BMG50]

Here are some rounds fired from a Bren, not sure of the manufacturer. Is it a ink or paint.

 

[TimG]

Mk. VII Ball, Kimberley, South Africa.

TimG

 

[ydnum303]

This was a varnish, not an ink, and was introduced in various colours during WW1 in order to help distinguish the various types of ammunition that had come into use. Its secondary purpose was to waterproof the join between the case and primer.

When the 7.62 came in to service, the existing practice was continued, as everyone was familiar with it.

What the actual formulation of the varnish was, I have no idea, but suspect it may well have been changed at various times over the last 100 years!