[/quote] Do you find , while case trimming is much reduced, that the neck / shoulder junction will thicken over many cycles?
This is what I have found with a 6 Dasher and 280 ai. This makes closing the bolt a bit harder than normal , so neck turn the base of the neck.
Improving a cartridge is not about velocity (for me), but getting it 'right sized' to give more opportunity to hit an OBT at reasonable pressures.[/quote]
I have seen that--but it also can happen in non-AI bottlenecked cases. But have also seen it in brand-new factory brass with relatively sharp necks, say around 30 degrees. Had a batch of new 6.5 PRC brass that apparently had the "dreaded donut" to a certain extent in maybe 10% of the cases, because it showed up after the first firing. Like you, I neck-turned the base of the neck to solve the problem.
