Had to grind off the top of the shell holder by .020". I don't have easy access to a lathe anymore to take it off the bottom of the die. Case shoulders were to far to the case mouth to chamber. First sized on my ancient RCBS Rockchucker, then tried the die on my new Hornady LNL Single stage Press, which actually has much less springback.
Comunicated quite a bit with Dave, head of technical and operations at CH4D.
He once tested Rockerchuckers and measured .015 to .017 spring from the top of the die lock ring. Was not worth sending die back just to grind the .020 off it's bottom.
Works fine now. 8x57 case stretched about 1mm, from 56.7mm to 57.7mm during resizing.
A lot less work than resizing and trimming the 270 brass.