You mean these? lolWasn't that a fad from the eighties or so? where you primed sized brass, Seated the plastic bullet to use for indoor target practice
Surprisingly fun when I can't make it to the range. It was a lot more fun before the cost of primers went to the moon. Also, very useful for teaching yourself how to shoot revolvers double action. I shot these a lot when I first got away from shooting revolvers single action only.