[Dick284]

For the most part I like Triggerpress's, Idea, he is explaining Partial Full Length Sizing.
I take fired cases, lube them, then smoke the neck and shoulder area with a wooden match.
I then set the Full Length sizing die high in the press, I work the case in and out while lowering the die looking for the point where the soot on the shoulder of the case just gets disturbed by the die body. At this point I attempt to chamber the case, if it goes easy I leave the die set where it is, If it still is a bit sticky I will lower the die about a 1/8 of a turn and repeat the chambering sequence, repeat the 1/8 turn if necessary, once things chamber smooth, set your lock ring on the die and get after it.
This method should provide a minimum of case stretch, while assuring good chambering. Of course this sytem fails if the fired cases are from a diffrent rifle.