I have two buddies that built 6.5-06AIs. Super easy, neck UP .25-06 Rem brass, seat the bullets touching the lands, fire form. No turning necks required, one pass through an expander from .255 to .262. Same OAL case as .30-06, which shrinks in length just like a .30-06 case would, no need to neck turn. We used R-P brass, since Rem & Win brass use the same brass thickness in the neck and shoulders, so no donut. Bought 500 pcs between the two, weight sorted to 1gr in two batches, had about 25pcs that didn't work in either batch. Still had 235 pcs in each batch, at half the price or less of Lapua. Prepped the brass, and they are on firings up to #6 or 7.