Oal gauge custom brass

[Snuby642]

So at a loss as to which brass to use for custom AOL case.

Fire formed to the chamber?

Or my bumped back brass?

I know only 2-4 thousands in auto or bolt but what is standard?

 

[XLR308]

Just use a piece of fire formed as long as your bolt will close easily on it.
That should give you somewere between .001-.002" of clearance and would be perfect.
New Lapua brass is only .0015- .002" under my fired brass in the 65 Creedmoor barrel Kelblys chambered for me so I wouldn't be hesitant to use a piece of new brass for a gauge.
It really just depends on your chamber and how close of tolerances you want although you could easily work out any differences based on measurements alone.