I bought the RF100 about a year and a half ago. I called Dillon and told them of the problems I was having with flipped primers using Win small rifle primers, we went thru the standard checklist, nothing seemed to work so I tried to live with it. I had finally had it and sent my RF100 back to Dillon, they sent it back and told me I had tightened the screw on the adaptor too tight and to run it loose. BS I had tried everything from so loose it almost fell out to snugged up before I had sent it to them. I then bought some Remington small rifle primers and they loaded the tubes perfectly over and over again. Dillon had sent me another blue adaptor and after thinking about it I measured the diameter of the Remington and Winchester primers. The Winchesters were ever so slightly smaller in diameter and I thought this might be the problem so I took some thin super glue and lined the inside of the blue adaptor by squirting a little in and rolling it horizontally to spread it evenly on the inside of the adaptor. I made sure it was all coated with a little glue and let it dry. I dumped a tray of Win SR and watched them all march up the ramp and down the tube, all the right way. I suppose the glue will wear off after some time but I'll put another drop in and touch it up.
My WLR and WLP drop just fine, just the dang WSR were giving me fits. Who know maybe it is a slight tolerance change at Olin that now make the WSR not work in the RF100. Possibly the small blue adaptor from Dillon has changed or it is simply the stacking of tolerances between Dillon and the WSR.