I’m getting there. I decided after much deliberation to use tin snips on the ends of the spent shotgun cartridges and then fold over since my first attempt resulted in very sharp edged buttons.
So…..I’ve cut off the plastic outer with scissors, knocked out the primer (which later forms the button centre) before drilling out the resin with a flat drillbit. Then using tin snips I’ve snipped all the way round before knocking in on itself with a hammer and crimping flat with pliers……..I’m doing 100! in the hope that after quality control theres 75 decent ones.