Hey Mr Texan, I too have been lurking......
Ditto all above posts essentially. I have had a good amount of blow by as well on American Eagle (Federal). I was most pleased to measure and find I am .308 on my rounds as well. My reload fodder is Hornady .310's which measured .309/.308 as well.
I shoot very nice groups with everything I send down the tube. Perhaps it is that I Zero for about 60yds and have a 3x9x50 scope
but my groups are fabulous. I am bummed out htat my reload equip for x39 is a complete resizing of the casing though....I will eventually may get a neck sizer only. This would help eliminate blow potentially.
Just wanted to give you "first post"......for the person waiting to buy the x39 in Rossi....DON"T wait. Mine was a close-out, maybe not true but I heard it was not being made any longer. Hopefully hogwash as the x39 is excellent for the kids - and adults too.
Remember -- I think the more we shoot the better these will become.