Im in the process of doing a complete refurbishment of a Sako AV for a customer.
Im also doing a bit off "back to basics" machining using my 4 jaw chuck instead of the 6 Jaw Bison, as thats being stripped down and totally cleaned today.
I clocked up the new barrel for the AV and chambered it using one of three chamber reamer holders I have - this time I chose my Gre Tan holder as the barrel (a chromoly Lothar Walther) was showing zero run out despite being a rather light (Standard Sako) profile - its real easy to distort the lighter profile barrels when clocking them up.
I check for concentricity at every step - create tenon; check, create thread; check, create bolt nose recess (if applicable); check and so forth right up to the chambering phase.
Anyway, once id chambered the barrel to headspace plus .003" I checked the rearmost edge of the chamber for run out.
Dial gauge is an Interrapid in 1/10000 increments (one ten thousanth of inch)
The tenon and chamber are still wet through from the flush system I use which is why its so messy….
I usually recon on getting 2- 3 tenths run out on most chambers and as close to zero on target or tactical rifle chambers - I'm more than happy with this one….