There's a spring on the RCBC Piggyback primer station. When it lets go it is gone. After the second one disappeared. I had RCBS send me 2 more (warrantied as usual) when I got them I tied a foot long piece of floss to one end. Put it on and went 6 months or so with no mishaps. Then it happened. This time it was easy to find and laying in the same area were the other 2 springs just under the edge of a box where they were hidden. Even the magnet did not pick them upB before.