Many times following the manufactures instructions (at least in the case of RCBS inless recently changed) will quickly lead to brass failure.
The reason is, manufacturing tolerences which in simple terms means nothing is "perfect" and exactly matches the published specs.
Therefore, Always size bottle neck brass the minimum amount that will allow brass fired in YOUR chamber to again chamber in YOUR chamber after sizing.
Will following the manufactures instructions allow you to make ammo that will fire in your gun?
The answer is almost always, YES.
However, it may also lead to rapid brass failure!! and less brass to chamber consistancy.
Having read only the printed instructions provided with RCBS dies, which I have used for many years, and the Hornady dies of more recent purchase, the "foot note" in the Hornady information is MUCH closer to reality then the RCBS info I have.
If RCBS has not already done so, we, the buying public would be well served if they would follow Hornady's lead in this situation.
The document I will be sending to "318" shortly, quotes the infomation spoken of above, and explains the reasons there is a MUCH better way to adjust our sizing dies.
Crusty Ceary Ol'Coot