Sizing consistency after annealing

[L.Sherm]

Have you ever tried not annealing at all?
And Parshal is correct on the donut thing, you cannot push them 100% out with a mandrel you gotta ream them out.

 

[Ekupp]

After chasing my tail on this, it became apparent that I had another issue with my brass. The sizing die was creating a belt on the base of some of the cartridges. The pieces that were not sizing at various increments of annealing were having this issue. I was having to crank down the dies to resize the now belted cases some size others would work past the belt and oversize the brass. This was creating my confusion and the reason I started this thread.

This particular brass is 6.5 Grendel Starline that was FL formed and loaded as 6mm arc. According to the internet this is happening with others that are using 6mm arc and to be clear this was happening after sizing once fired brass. Now on to figure out if this is a chamber/brass or die issue. Its my assumption its only happening with near pressure loads fired from my semi auto. For those not familiar 6mm ARC has two sets of load data with different pressure max's, one for bolt guns and the other for semi autos. These were shot in a semi and no where near max for bolt guns but near max for semi autos. Next step is to see if the same thing occurs with brass fired in my bolt gun.

My primary goal in annealing is to get consistent full length sizing. What I have noticed with certain sets of brass is that after annealing 70% of cases will be +/- .0005" of my target. 15% will be stubborn and not size and 15% will under size by .002-.004.

As an experiment I kept annealing the stubborn pieces for .1s longer till I got them to the proper size.

So, am I not annealing long enough or am I annealing too long and starting to get 15% that are too relaxed with the stubborn ones just needing to get adjusted to the baseline of the batch?