I am in the process of converting a Savage model 12 chambered in 270WSM to a 6BR. I re-configured the bolt, installed the new barrel and set the headspace with a Clymer BR go gauge. I used the tape trick as a No Go gauge and the bolt would not close. I then tried several Lapua cases. The bolt closed on both the taped and untaped cases. The barrel is a McGowen and was chambered specifically for Lapua brass. Should I set the headspace using the case instead of the go gauge? I seem to remember reading that Lapua 6BR brass has slightly different dimensions than Rem or Norma brass.