Re: New Lapua brass, can you just reload it?
I chamber each unmodified case, to ensure they at least do that reliably. It's not a major chore, and it can eliminate chagrin at the range, in mid-match.
I don't trust any brass solely on the basis of its reputation, and treat it all the same. For my purposes, this would tend to negate any perceived advantage Lapua brass might enjoy in the eyes of others. My own preference is for Winchester brass, based on cost, local availability, and a personal history of reliable performance.
My neck tension/maintenance technique involves neck diameter reduction for only a fraction of its length.
I do this by emplying a conventional F/L die and sizer ball, with the die backed off so it resizes only a portion of the end of the neck.
How much length is determined by a 'spin test'. If a seated bullet can be made to turn within the neck, using only a thumb and forefinger; then there is not enough neck tension, and the die needs to reduce neck diameter for a bit more of the neck's length. When the bullet won't budge, we're there.
Since brass working affects springback, this tension value is a moving target. So the 'spin test' should be performed for each reloading cycle. This should allow neck tension to remain relatively constant regardless of neck hardening, within reason.
Obviously, I do this with all new brass as well. You may find that a bullet will seat into a new, unsized case and not spin. But after it fires and forms to the chamber's true neck expansion value, the process should become reliable.
Greg