@ 05:03 am (GMT)
Ben Lawwell i knocked up the jig the other day.
cost me about $15 for the dome nuts and some threaded rod, as i already had the dial gauge and magnetic base.
i can see all my fire formed brass has .001" or less runout.
my 223 handloads are mostly the same but a few had upto .005" bullet runout, i suspect this is from occasionally not quite sitting the bullets square into the neck when seating (seems easy to do with the little 223) (the bigger rounds are easier to sit the bullet straight and are pushed further into the neck which i think helps pull them back into alignment)
i have some 30-06 once fired donor brass which i have full length sized that measured .003-.009" runout, tried running it through the lee collet die but that only improved it by .001-.002 at best.
the same batch of brass that i used for some load testing has .001" or less runout so i after fire forming the brass should be all good.
after seating bullets i will try bumping them with the old block of timber with a hole drilled in it, see if that gives an improvement.