see the pic of a push thru sizer i made for swedging .452 bullets down to .446 for use in a 71/84 mauser i picked up for a song. buying custom diameter bullets would cost nearly a buck a pop, but you can get .452 for dirt cheap. i drilled a 7/8 bolt axially to 7/16 and used a split rod and sandpaper flapper to polish in a taper that accepts .452 and sends out .446. the bolt screws into any single stage press, and the matching ram extension snaps into the shell holder socket. presto. dirt cheap. an hour on the lathe. no idea how much diameter reduction can be done this way, but not a lot.