I am about to build a switch-barrel rifle in 220 Swift and 240 Cobra which is the Swift necked up. Would a Redding bushing die in 220 Swift work for both by just changing bushings? How would the best way to get an arbor type seating die for the 240 Cobra? I would think that I could have a Wilson 220 Swift seating die bored out to 6mm fairly easy, but are there options I am overlooking? Thanks. Tom ???