Have a 20plus year old 450 bought it when i got into uspsa did the upgrades many years ago to make it a 550 now I see there is a frame avaible to make a 550b anyone changed to the new fram , how hard is it to do ? also can some one tell me about the refurbishing of a press, I here Dillion does, have probably loaded 100,000 rnds on this one thru the years love my press thanks for any info...