concentricity issues?

[AlanF]

...observations would suggest that minimizing runout is a sizing issue more than a seating issue if all is well with the seating die, and assuming necks are concentric....

I'll concur on that Bruce, particularly FL sizing seems to upset the neck alignment with any of my FL dies.

...my fclass rifle can hold less than 0.2 moa elevation for 15 shots at 300, but it is very hard to duplicate that or come close at longer ranges with the same consistency, because there is more to go wrong between you & the target.
bruce.

Of course both high ES and wide BC variation will hardly show up at 300, but may cause a lot of elevation at the longs.

Alan

[RDavies]

AJr, What I found was that the seating stem was pushing the bullet in by the tip which was hitting on a flat top surface in the stem, not the tapered cone. If the tip was canted over to one side of the stem when I seated the bullet, that is the way it stayed. It squared itself up a bit, but the tip was being being hit at the same time or earlier than the cone of the seater touched the ogive. It was OK with the 165-168 sierra bullets, but when I longer ogive Berger 168 or sierra 175 bullets, the bullets bottomed out on the tip.

Update. I just drilled out the seater stem a bit last night and it fixed the issue with hitting the tips on 168 Bergers and 175 sierras. Concentricity is now down to .003-.002, good enough for now.
I had the same problem a few years back when I was using 90gn bullets in my 22/6mm imp. The 90gn .224 bullets bottomed out on the top of the seater stem.