Dillon 550B Been sometime since I posted and a long time since I reloaded, I recently (well last year), tore apart my 550B, and re-lubed all the components punching out all the pins, etc, and am putting the finishing touches on it. Runs real nice now. Anyway, I never put the primer tube back on the plate. And I had a left over bolt with a sunken hex head on it. Looking around, found where it went, but I can't recall what it is used for? I don't think I ever adjusted in 15+ years, if that is what it is. If you continue to screw it in, it comes out the other side of the aluminum(?) piece. Here is the picture, what is the purpose of this hex head sunken bolt? It is circled in RED. Thanks gents, and take care.