6BR headspace question

Tokimini · 03-20-2014, 07:42 PM

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.

**Hotolds442** · 03-20-2014, 07:52 PM

New Lapua brass measures 1.556-1.557". SAAMI spec for the 6mm BR Norma case is 1.560". By contrast the OAL spec for 6mm BR Remington is 1.520". The Lapua brass is headstamped 6mm BR Norma-Lapua. Use your go gauge as the no go and you should be just fine. To do that, notice where the bolt handle stops now on your no-go gauge. Insert the go gauge and set the bolt handle to the same position, screw the barrel in, and tighten it down on the gauge. The barrel nut will provide enough pull-back to make it about perfect.