My uniflow came with my rcbs kit I bought 14yrs ago. When the px up here used to sell reloading stuff. I lost the inserts for the different case mouths oh well. Only thing I done to it was put the baffle in it.
Contact RCBS and they will probably send you the inserts for free. They have the best customer service I've ever experienced- but haven't had to use them much over the years...
