Looking to build a 20 vartarg using a Savage Target action.

Who to look at for a barrel?

Which dies do I need? A set of dies for a 221 Fireball and a bushing to neck the brass down to .204 correct? What exactly is this bushing (I understand the principle) where do I get it- a part # or picture would be great. Onve the brass is sized do I keep using the bushing to re-sixe the neck or someone make 20 vartarg dies?

What else do I need to know? Lots of newb questions- just trying to sort it all out.