Thread: Ridge in once fired .303 brass

In the past I fired some ex mil .303 ,through my no4mk1 ,only to experience multiple head separations.lucky i had a rattail rasp and latterly a .303 case removal tool to remove remainders from chamber .on inspection -a very tiny but bright ring evident on the case in front of flange . inspected remaining stocks -see the ring -round rejected.
In this case personally id get rid of those cases gut feeling ??????some type of metal fatigue.I stand to be corrected of course by those more erudite in the reloading field.