the recoil lug is pinned to the Stiller action,,when my smith chambered the first 6.5x47 barrel he wrote down the headspace #s and he can chamber new barrels and all I have to do is put it in a vice and spin the action off with Rem 700 action wrench apply a little anti seize on threads and spin new barrel on and the headspace will be right,,as long as he gets it right I cant mess it up as long as I use same bolt and recoil lug,,the barrel has a shoulder and just snug it up,,it is not like a Savage where you can adjust headspace,,it is either right or wont work
but the last 2 BRDX barrels I didnt even have to adjust my fl size die after switching barrels,,