What Did you find for dies? If you are working with Redding or RCBS you most likely will get along very will with your bullet seater die after removing the bullet seater stem. Design of the Hornady bullet seater die does not lend itself well to this preforming operation.
I and many others have done have used the bullet seater die for a 1st of 2 die process for necking down 221 brass with good success.
Note: Polishing the inside of both the full length and the bullet seater/1st form die with flitz polishing compound will improve the function of these dies for forming purposes.
http://www.varmintal.com/arelo.htm#Polish 
