I am having no luck finding anything, so I am going to give you a possibility. I doubt that four letters are the initials for one person. Many of the artists I know don’t even use a middle name. So, I am going with two different artists. I can’t really make out the first set of initials and couldn’t find any bead makers that went with a conjoined JP. That led me to the AC which I find a name Albert McCabe associated with such a hallmark. We buy beads from an artist by the name of James McCabe, nice beads like these. I did research on his name and didn’t find silver beads, but did find a similar AC. This is a big assumption, but many times that is what we have to go on. Good luck.