Do I need to close my adjustable GB a little?

[ss355]

I'll have to check, but I don't see any flattened primers with the Hornady 123 Amax load. In my 24" .264 LBC barrel I do see ejector marks regularly, but I thought that was a product of the 24" tube with a rifle-length gas system. I don't have any brass I can trace back to the 16" mid-length (November of last year was the last time I shot it), but I don't recall seeing either flattened primers or ejector marks.