The term, "Full Length" as it is used in modern bench rest, is really "partial full length". A special die is custom made to reduce the body diameter minimally while "bumping the shoulder" back .001-.002". This allows a round to be chambered without disturbing the rifle in the front rest. When neck sizing only, the cases become tighter after a few firings and will require considerable pressure on the bolt to chamber a round. Partial full length resizing, with shoulder bump, eliminates this problem.
