And another thing...
It just occurred to me- Say I fire a factory or standard .257Robts cartridge in my Improved chamber. The case should now conform to the inside dimensions of the chamber, right?
So if I resize that case in a full-length Ackley Improved die, what will its dimensions now be? It should squeeze down the neck and the body to some extent but surely it won't size all the way down to the standard Roberts case dimensions... ?
None of my reloading manuals has that data.